Sustainability at Navistar: A Model Distinguished by Sustainable Innovation, Proactive Product Stewardship, and Sound Science Thomas W. Hesterberg1,*, William B. Bunn1, Thomas Slavin1, Jason Malcore1, MacKenzie Porter1, Neal C. Grasso2, Christopher M. Long2, and Bruce Harrison3 1 Navistar, Inc., Chicago, Illinois, USA 2 Gradient, Cambridge, Massachusetts, USA 3 EnviroComm, District of Columbia, USA Prepared for Submission to Business Strategy and the Environment August 2011 * Corresponding author address: Navistar, Inc. 303 E. Wacker Drive, Suite 360 Chicago, IL 60601 Telephone: 312-927-2697 Email: Tom.Hesterberg@Navistar.com. 1 Abstract [150 word limit; currently at 149 words] While corporate sustainability is broadly interpreted to mean ensuring success in the present without compromising the future, a well-accepted workable definition has remained elusive. Sustainability is often defined using a set of criteria or metrics that address the recognized environmental, social, and economic pillars of sustainability. However, standard metrics fail to account for how companies deal with operational challenges to their sustainability and viability. As a 175-year-old diesel engine manufacturer, Navistar, Inc. has developed a sustainability model to address not only the three pillars but also its significant business challenges, including those related to health concerns over its diesel products and environmental and employee legacies. Featuring a commitment to sustainable innovation and product stewardship and reliance on sound science, Navistar's sustainability model has evolved in response to its unique operating environment, illustrating the benefits of designing sustainability strategies to address specific business challenges rather than a standard set of criteria. 2 Introduction [3,000 to 7,000 word limit; currently at 6,921 words- not including references, figures, tables] The advent of the modern concept of sustainability is often attributed to the United Nations World Commission on Environment and Development (UN WCED) publication, Our Common Future (often referred to as the Brundtland Report, after the commission's chair, Gro Harlem Brundtland), which defined sustainable development as "[meeting] the needs of the present without compromising the ability of future generations to meet their own needs” (UN WCED, 1987). The term was more formally defined in the Rio Declaration on Environment and Development (UN, 1992), and was further developed at the 2002 World Summit on Sustainable Development where the concept of the "three pillars of sustainable development"– environmental, social, and economic – was introduced (UN, 2002; Kates et al., 2005; CA Rich Consultants, 2005). Despite the UN's interpretations of sustainable development, a well-accepted workable definition of sustainability has largely remained elusive (Marshall and Toffel, 2005). This is in part due to sustainable development being an evolving concept that can be adapted, and in effect redefined, to fit different situations (Kates et al., 2005; Cowan et al., 2010). Today, it can be argued that sustainability is more clearly defined by the guidelines and metrics that have arisen to evaluate it than by any formal definition (Cowan et al., 2010; Marshall and Toffel, 2005; Belu, 2009). Among the more prominent sustainability guidelines are those of the Global Report Initiative (GRI) that were first issued in 2000 and then updated in 2006 (GRI, 2006, 2010). The GRI guidelines, which measure corporate sustainability performance with respect to laws, norms, standards, and voluntary initiatives, provide a consistent and comprehensive framework for 3 sustainability reporting that allows companies to evaluate their progress over time and against other companies. In addition to the GRI guidelines, the Dow Jones Sustainability Index (DJSI) and the International Organization for Standardization (ISO) environmental management standards (e.g., the ISO 14001 standards) have also gained usage as sustainability benchmarks. [might be good to mention ISO 26000 corporate social responsibility standard here] Cowan et al. (2010) identified four key components that are highly prevalent among large corporations having comprehensive sustainability programs: (1) empowered leadership with a commitment to sustainability, (2) standardized reporting, (3) third-party evaluation of sustainability programs, and (4) ISO 14001 accreditation. Although these components are common among corporate sustainability programs, Cowan et al. (2010) and others (Harrison, 2009; Marshall and Toffel, 2005; Kates et al., 2005; Belu, 2009; Satterfield et al., 2009) have emphasized the variety of different paths companies have taken in developing and implementing corporate sustainability programs in the absence of established rules, regulations, or guidelines for sustainable business practices. In general, corporations have largely taken it upon themselves to define their own visions of sustainability and to develop models for reducing overall environmental and societal impacts while satisfying profit goals and economic growth. Disparate approaches and models have emerged, with varied results, as companies have attempted to adopt more sustainable business practices and to balance economic, environmental, and social dimensions of sustainability (Adams, 2006; see Figure 1 that contrasts the desired balance of economic, environmental, and social dimensions with reality, where economic development often outweighs environmental protection and social development). [maybe after the citation , shorten and say something along the lines of “see Figure 1, where economic development often outweighs environmental protection and social development.] 4 Navistar, formerly known as International Harvester, began more than 175 years ago, well before the modern concept of sustainability. Like many companies throughout the world, Navistar has embraced the modern concept of sustainability, developing a sustainability model that addresses the recognized environmental, social, and economic pillars. Navistar's sustainability model has also been shaped in response to a unique set of challenges posed by its history and operating environment, including those related to health concerns about its diesel products, environmental and employee legacies from its past, and never-ending technical demands to reduce emissions and increase the energy efficiency of its products. In this paper, we discuss key components of Navistar's sustainability model, beginning with an overview of corporate initiatives to address the recognized pillars of environmental, social, and economic sustainability. The main focus of the paper is on Navistar's sustainability initiatives that address its unique business challenges, including those related to its products (emission reduction, energy efficiency and health concerns) and those related to its legacy (environmental and employee related). Navistar’s record in breakthrough emissions-reduction engineering (e.g., a Navistar school bus utilizing green diesel technology was certified as first to achieve aggressive proposed California and federal standards) is linked to benchmarked leadership (Harrison 2008). As companies continue to shape their sustainability models and identify potential model components in the absence of prescriptive governmental regulations and requirements, the objective of this paper is to describe the Navistar sustainability model and highlight some of its unique elements. Given its clear contributions to Navistar's business success, Navistar's sustainability model can offer insights to other companies working to define and implement corporate sustainability programs. 5 Overview of Navistar Initiatives to Address the Three Pillars of Sustainability Like many companies, Navistar's sustainability model incorporates numerous elements that address the recognized pillars of environmental, social, and economic sustainability. Several elements of these pillars have been embedded within the core values of the company for many years. For example, Navistar was a charter member of the National Safety Council in 1913, and established industrial safety committees and employee welfare programs more than 100 years ago and, thus, decades before governmental requirements from agencies such as the U.S. Occupational Safety and Health Administration (OSHA). In addition, Navistar established a nofault worker’s compensation program prior to establishment of state compensation laws in the early 20th century. As discussed below, in addressing the three pillars, Navistar's sustainability model contains several elements that are common to many of today's corporate sustainability programs, including a commitment to environmental accreditation, challenging goals for energy consumption and greenhouse gas emissions, and other pioneering initiatives, including its voluntary, incentive-based wellness programs. Environmental Sustainability Similar to other corporate sustainability programs, Navistar has pursued environmental accreditation, namely ISO 14001 certification, as a key effort related to environmental sustainability. ISO 14001 outlines the standards for an environmental management system (EMS), providing companies with the methods for developing a systematic approach to minimizing the impact of their operations on the environment, ensuring their operations comply with applicable laws and regulations, and forging a process for continuous assessment and 6 improvement of these processes (ISO, 2004). In order to become an ISO 14001 certified location, an organization must obtain "written assurance (the certificate) by an independent external body that it has audited a management system and verified that it conforms to the requirements specified in the standard." (ISO, 2010). While certification is not required to implement an ISO 14001 EMS, certification provides an additional level of credibility to the management system, and further demonstrates the company's commitment to environmentally friendly and sustainable business practices. As of 2010, twelve of Navistar's 18 manufacturing facilities have been certified under ISO 14001 (Navistar, 2010b). The remaining operations are new acquisitions or currently undergoing structural changes and will pursue certification in the future. Keys to Navistar's strong EMS program include regular internal audits, adherence to strict operational control procedures, and compliance with all environmental laws and regulations (Navistar, 2009a). Stemming from its commitment to incorporating sound environmental management practices into its operations, Navistar has made great strides in reducing energy consumption and greenhouse gas (GHG) emissions. The company has set a corporate-wide goal of reducing electricity usage during production periods by one percent annually, and during non-production periods to a level 35 percent of production loads by the year 2013 (Navistar, 2011). For greenhouse gas emissions, Navistar has established a goal of an absolute 20 percent reduction in GHG emissions by 2013, compared to 2008 (Navistar, 2011). Navistar has already made substantial progress towards meeting these goals; for example, GHG emissions in 2010 were 23 percent less compared to the 2008 baseline year (Navistar, 2011). Importantly, efforts have occurred at all levels of the organization. For example, Navistar's dealerships are remaking their facilities with state-of-the-art approaches to energy conservation and GHG emissions reductions, 7 including one Minnesota dealership that installed a geothermal heating system, along with LED signs, leading to a projected annual savings of $15,000 (Navistar, 2009a). Navistar has also implemented an aggressive program to reduce waste generation at its facilities, with the ultimate goal of creating zero waste facilities. From 2003 to 2010, Navistar decreased non-hazardous waste generation by more than half from approximately 75 million pounds to less than 30 million pounds (Navistar, 2011). As shown in Figure 2, Navistar reduced releases of Toxic Release Inventory (TRI) chemicals at its US facilities by more than 200 tons per year between 2001 and 2009. In coordination with efforts to reduce waste generation at its facilities, Navistar has also worked to promote recycling, resulting in an increase in the company's recycling of non-hazardous materials from 20 million pounds in 2002 to more than 40 million pounds in 2009 (Navistar, 2011). Social Sustainability Navistar has focused on achieving greater social sustainability through a number of prominent employee and community initiatives, in particular a variety of voluntary, incentive-based wellness programs. Navistar has long recognized the large cost of health care (e.g., in excess of 2 percent of revenue for several of the past years), as well as the effect of health and wellness on workforce productivity. Through its multi-faceted "Vital Lives" program that provides a comprehensive approach to health, safety, and productively management, Navistar seeks to empower its employees to improve their own individual health and ewllness. This program is designed to address each of the three stages of prevention and thus both the cost and productivity aspects of health: 8 Primary prevention programs help people maintain a healthy and injury-free status and reduce smoking, obesity, and other risk factors. As a key part of its efforts, Navistar offers employees an annual, confidential Health Assessment (HA) to identify ways to address behaviors that increase the risk of current and potential health issues. "Trucking Across North America (TANA)," a 13-week competition where employees log in their weekly exercise miles, encourages exercise and teamwork. “Spring Tune-up” is a sixweek exercise and nutrition program. Flu shots are provided and preventive exams and screenings are encouraged. Secondary prevention manages risk to prevent disease or injury among those with risk factors such as inactivity, high blood pressure, high cholesterol, smoking, obesity, and stress. A health risk appraisal is offered and a $200 incentive is provided to those who complete two programs such as TANA, telephonic health coaching, or other programs targeted at risk factors. Programs are administered by independent third parties to preserve confidentiality. Tertiary prevention manages injury and disease to reduce impacts and prevent progression to catastrophic conditions. Diabetes education and testing, rehabilitation and return to work programs, and telephonic health coaching are some of the tools used in this effort. These programs have been demonstrated to reduce health risks, promote evidence-based care, and encourage smart healthcare spending. (Navistar, 2009a; Hunnicutt, 2003). In addition to prevention, Navistar has further addressed cost through competitive pricing in vendor and 9 provider network selection and program design that encourages cost effective utilization (e.g., copayments, deductibles, generic drug pricing). Overall, as shown in Figure 3, Navistar health care costs have consistently fallen in recent years as the cost of US health care has risen about eight to 12 percent. Navistar's recently added Sustainability PROMISE, standing for Personal Recognition of My Individual Sustainability Efforts, as an employee-oriented social sustainability initiative. This program, which was made company-wide in June 2009, encourages employees to engage in safe and healthy behaviors, to make life choices that save energy and are environmentally friendly, and to volunteer their time for community-improvement efforts. Community-related social sustainability initiatives include support for numerous local arts and development programs, but also include Navistar's efforts to work with resource-constrained schools to provide students with diesel technician and other industry-related training. While addressing the trucking industry’s chronic shortage of diesel technicians, these programs have offered thousands of students a head start toward a meaningful, stable career path. For over a decade, Navistar has collaborated with the Chicago Vocational Career Academy (CVCA), an inner-city high school on Chicago’s South Side, on a three-year diesel education program that has trained hundreds of inner-city youths as qualified diesel truck and engine technicians. Similar diesel education programs have also been instituted in additional Illinois and Indiana schools, with plans to expand to South Carolina (Navistar, 2011). In addition, Navistar's South American engine subsidiary MWM International has run the Formare School program since 1987, introducing disadvantaged 16- to 18-year-olds to manufacturing, engineering, and 10 administrative careers. Among other social sustainability initiatives, Navistar has also promoted greater environmental awareness through such programs as its America's Greenest School contest, where schoolchildren submit essays on the steps their schools take to protect the earth to compete for prizes such as a new hybrid school bus. Economic Sustainability As a company that has been in business for 175 years through mergers, acquisitions, and periods of both expansion and contraction, Navistar's longevity provides strong evidence of economic sustainability. Strategies must change over time to adapt to changes in business needs and conditions. Factors such as wars, famine, economic depression or growth, and government policy require strategic readjustments. Navistar currently has three key strategies for economic sustainability – 1) producing innovative products focused on energy efficiency, emissions reductions, and hybrid technologies; 2) achieving a competitive cost structure that capitalizes on savings from reduced energy consumption, improved employee health and safety, and efficient product distribution; and 3) delivering profitable growth through investments in markets that are less cyclical in nature, such as defense products, recreational vehicles, parts, global products, and advanced technologies. Importantly, many of the elements of these key strategies for economic sustainability also contribute to environmental and social sustainability. Navistar's focus on sustainable innovation (discussed in detail in the next section) is a driving force to its economic and environmental sustainability. Through basic scientific research and technological innovation, Navistar has developed advanced diesel engine and emissions control technologies, as well as hybrid and all-electric truck technologies. Importantly, its engine and emissions expertise have become a competitive market advantage. With global reductions in 11 diesel emissions regulatory limits, emissions will continue to drive the trucking industry, allowing Navistar continued opportunities to leverage its emissions expertise and achieve economic sustainability. Navistar Sustainability Initiatives to Address Unique Business Challenges In addition to developing its sustainability model around the three sustainability pillars, Navistar has also shaped key elements of its model in response to its unique business challenges. In particular, as a company that designs and manufactures diesel engines, trucks and buses, and engine parts, Navistar faces public concerns over potential diesel health hazards and a regulatory environment of increasingly stringent emissions targets that challenge engineering capability. Sustainability in this context requires product innovation to reduce emissions and improve fuel efficiency as well as product stewardship using sound science to accurately assess public health risks and to help inform regulatory decisions. Navistar's sustainability model has also evolved to address business challenges involving environmental and employee legacies from its 175 year past. As discussed below, Navistar's experiences illustrate the need to design sustainability strategies to fit specific business environments rather than a standard set of sustainability criteria. Sustainable Innovation at Navistar Sustainable innovation at Navistar encompasses both making existing products better and developing new products with the dual goal of reduced emissions and higher fuel efficiency. Since launching its first production diesel engine in 1933, a 50-horsepower four-cylinder engine for stationary and agricultural applications, Navistar has produced innovative engines for 12 agricultural, construction, military, and on-highway applications. Diesel engine technology has been radically transformed in recent years, with Navistar's efforts helping drive these industrychanging innovations. In addition, Navistar has actively pursued the development of new alternative engine technologies, including diesel-electric hybrid and all-electric trucks and buses. Figure 4 provides a timeline of key accomplishments related to Navistar's recent efforts at sustainable innovation. As described below, Navistar has constructed a successful model of sustainable innovation using a combination of different approaches, including internal research and development, collaborations, and sometimes approaches diverging from the prevailing industry position. Development of Cleaner Engines For decades, the diesel engine has been recognized for its power, durability, and efficiency. In addition to these beneficial qualities, diesel engine emissions are well-known to consist of a complex mixture of particulate species, condensable vapors, and gases that includes pollutants regulated by the US Environmental Protection Agency (US EPA) as criteria air pollutants (e.g., particulate matter (PM), nitrogen oxides (NOx), carbon monoxide (CO)) and as hazardous air pollutants (e.g., formaldehyde, benzene, polycyclic aromatic hydrocarbons). Due to concerns regarding possible DE health effects, US EPA has implemented increasingly stringent regulatory standards for on-road heavy-duty diesel engines (HDDEs), beginning with a smoke standard for the 1970 model year and continuing through the tightened PM and NOx emissions limits for the 2007 and 2010 model years, respectively. As shown in Figure 5, US EPA has now reduced both PM and NOx emissions requirements for HDDEs by approximately 99 percent compared to pre1988 unregulated emissions. Other regulatory bodies, including the European Union (EU) and 13 the California Air Resources Board (CARB), have also adopted stringent DE emissions standards. With its efforts to develop low-emission, advanced technology diesel engines, Navistar has played a key role in the emergence of what has been termed New Technology Diesel Exhaust (NTDE) (Hesterberg et al., 2011). The solution to the 2007 emissions requirements, namely the integrated, multi-component emissions reduction systems (advanced diesel engines, modern electronic fuel injection systems, ultra-low-sulfur fuel, special lubricants, and exhaust aftertreatment devices) is now standard for today's heavy-duty diesel engines. Although the industry as a whole has adopted similar approaches to meeting the stringent US EPA PM standards for model year 2007 engines (i.e., aftertreatment configurations featuring cDPFs), it is important to note that there are divergences in how diesel engine manufacturers have elected to meet the stringent NOx standards for model year 2010 engines. New regulatory requirements sometimes challenge the limits of technology and force manufacturers to choose a technology path that is not yet fully developed. Navistar has taken a different approach than most of its competitors, electing to continue to push the design limits of diesel engine technology, selecting “advanced” exhaust-gas recirculation (EGR) technology rather than selective-catalytic reduction urea (SCR-Urea) technology to achieve the NOx limits. Advanced EGR technology is a stand-alone in-cylinder approach that lowers NOx through the recirculation of large volumes of air (cooled diesel exhaust) through the engine cylinders. SCR-Urea technology is an aftertreatment approach that converts urea to ammonia that reacts with NOx in the exhaust stream. Each technology has its advantages and drawbacks. EGR requires a greater investment in research and development but offers constant NOx control over the entire duty 14 cycle. SCR-Urea technology, on the other hand, offers an off-the shelf solution similar to technology that has been used in Europe for several years but does not work when the exhaust temperature is below 250°C, which can be a significant portion of driving time for trucks in inner cities. Navistar has pursued the EGR approach as a more sustainable option that does not require drivers to carry and maintain a tank of urea and that reduces NOx at all times during vehicle operation. Holistic Approach to Diesel Vehicle Energy Efficiency The fuel efficiency of diesel vehicles can be increased through both improvements to diesel engine design and aerodynamic product design. Engine design is one key factor, beginning with a 30 to 40 percent fuel efficiency advantage of diesel engines compared to gasoline engines and improving engine designs to further fuel economy gains. For example, reduced weight and improved heavy-duty diesel performance have enabled engines to surpass the fuel efficiency of prior models by 9 to 13 percent (Navistar, 2008a). The diesel engine itself is only one piece of the fuel economy puzzle, with aerodynamics and tire design providing additional opportunities for energy reduction and mileage improvements. Navistar has pioneered advances in aerodynamic product design, obtaining multiple patents for design components on tractors that reduce high pressures in front of the tractor and that streamline air movement along the sides and onto the tractor (Navistar, 2007a, 2007b). Improved aerodynamics are credited for the improved energy efficiency of the long-haul trucks, which bettered the fuel economy of the leading competitors in the advanced classic long-haul category by 20 percent upon its launch in 2008 (Navistar, 2008a). The first aerodynamic-styled Class 8 truck to gain US EPA certification as a SmartWay truck, an honor that recognizes fuel 15 efficiency improvements and reductions in greenhouse gas emissions, was a Navistar truck. (Navistar, 2008b). Aerodynamics innovation requires not only in-house expertise in aerodynamic design, but also creative partnerships and extensive third-party testing. For example, in early 2010, Navistar partnered with the U.S. DOE's Lawrence Livermore National Laboratory, NASA's Ames Research Center, the U.S. Air Force, and other industry partners to conduct full-scale wind tunnel tests with a 53-foot trailer. Testing was performed in the world's largest wind tunnel at NASA's Ames Research Center to support the development of test drag reduction devices, which are projected to increase fuel efficiency by up to 12 percent (LLNL, 2010). Prior to this, in 2008, the company was selected by the U.S. Department of Energy to participate in a project aimed at accelerating the development of advanced aerodynamic trailers for reducing fuel consumption. Most recently, Navistar was awarded more than $37 million in federal funding to partner with the U.S. Department of Energy (DOE) in its efforts to develop a SuperTruck with a fuel efficiency improvement of 50 percent. As part of this project, Navistar will develop and test technologies to improve truck and trailer aerodynamics, and make advances in combustion efficiency, waste heat recovery, hybridization, idle reduction, and reduced rolling resistance tires (Navistar, 2010a). Advanced Technologies- Hybrids and Electric Vehicles Navistar's commitment to sustainable innovation is further illustrated by its extensive efforts to develop and commercialize advanced diesel hybrid and all-electric technologies. As shown in Figure 4, Navistar has developed alternative transportation technologies, including the production and delivery of the first hybrid school bus in the United States in 2007, line 16 production of the first hybrid commercial truck in 2007, and the 2010 development of the first medium-duty commercial vehicle to receive US EPA certification as a clean fuel fleet vehicle and CARB certification as a zero-emissions vehicle. Diesel-hybrid technology offers gains in environmental sustainability compared to standard diesel technology due to both reduced emissions and improved fuel economy. For example, Navistar’s diesel hybrid electric truck emits as much as 33 percent fewer hydrocarbons and 35 percent less NOx than standard diesel trucks, with fuel savings of 30 to 40 percent (Navistar, 2008a). Moreover, fuel savings can exceed 60 percent given the engine-shutoff capability of the vehicle that allows for the zero emissions, battery-powered operation of equipment such as an overhead utility bucket (Navistar, 2007c). With a projected range as high as 100 miles per charge, Navistar's all-electric truck is a zero-emissions vehicle that, depending on the source of electricity, is estimated to reduce annual CO2 emissions by as much as 10 tons per vehicle compared to a fossil fuel powered truck with similar duty cycle (Navistar, 2009b). Navistar has used collaborative partnerships with both industrial and governmental entities to help move forward its innovative development of advanced diesel-hybrid technology. For example, Navistar partnered with Enova Systems, Inc., a developer of hybrid electric vehicle and electric vehicle drive system technologies, to commercialize the nation’s first hybrid school buses. By pairing an Enova hybrid-electric powertrain with a Navistar advanced diesel engine, Navistar's hybrid school bus is estimated to reduce emissions by up to 70 percent while improving fuel efficiency by up to 70 percent, contributing to estimated fuel savings of 800 gallons of fuel per bus per year (Navistar, 2007a). Through a private-public partnership with UPS, Eaton Corporation, and US EPA, Navistar developed a hydraulic-hybrid delivery vehicle that is projected to achieve fuel economy gains of 45 to 50 percent and reductions in CO2 17 emissions of 40 percent (Navistar, 2008a). In April 2009, Navistar was selected for participation in DOE's Plug-In Hybrid Electric Vehicle (PHEV) Technology Acceleration and Deployment Activity Program, receiving a cost-shared award of up to $10 million to continue the development of plug-in hybrid bus technology (Navistar, 2009a). In addition, in August 2009, Navistar was awarded a $39 million federal DOE grant to develop and build all-electric commercial vehicles (Navistar, 2009a). Product Stewardship at Navistar Traditional diesel emissions produce visible soot, helping create a perception of diesel as a dirty technology. Even today, after advanced engine technology has all but eliminated diesel soot emissions, public concern remains. Potential health risks from inhalation of diesel exhaust have been the focus of scientific and regulatory scrutiny, as well as numerous media reports, for decades. Despite the hundreds to thousands of research studies addressing DE health effects, there still remain uncertainties in the state of the knowledge regarding the human health risks posed by real-world DE exposures (US EPA, 2002; Hesterberg et al., 2005, 2006, 2008, 2011). These uncertainties are due in part to limitations inherent in the different types of observational and experimental studies conducted to investigate DE health effects, as well as difficulties in distinguishing environmental DE exposures from many other non-DE sources of the same air pollutants, including tobacco smoke, gasoline engine exhaust, tire-wear and road debris, combustion of wood, paper and waste, and meat-cooking fumes. In addition, diesel exhaust is a highly complex mixture that varies widely depending upon engine type, fuel type, and operating conditions. The remaining uncertainties in the state of the knowledge regarding DE health effects underscore the importance of a rigorous product stewardship program for identifying and evaluating the scientific evidence relevant to the potential public health impacts of diesel engine 18 technology, and for acting in a proactive fashion to address any potential issues that may be identified. As discussed below, Navistar has instituted a formal product stewardship program aimed at using sound science to understand and limit any potential adverse health effects from its products, which has become a key component of Navistar's sustainability model. Critical Assessments of the Diesel Health Effects Evidence As a central focus of its product stewardship program, Navistar has supported scientific research into diesel health issues. These efforts have included spearheading critical reviews of the DE health effects literature for cancer and non-cancer health effects (Hesterberg et al., 2006, 2009, 2010, 2011). There are a number of prior hazard assessments of DE (e.g., IARC, 1989; US EPA, 2002, NIOSH, 1988; CARB, 1988) that have generally relied on historical DE studies (i.e., pre2000 studies, predominantly of pre-1988 diesel engines) to conclude that sufficiently high levels of DE are linked with increased risk of cancer (specifically lung cancer) and non-cancer health effects. These include the International Agency for Research on Cancer (IARC, 1989) assessment that classified diesel exhaust as a Group 2A carcinogen (i.e., probably carcinogenic to humans), and the US EPA (2002) assessment that concluded that the weight of the evidence supports a "likely" role for DE in the risk of lung cancer. Importantly, US EPA (2002) did not develop a quantitative estimate of cancer unit risk for DE, citing the large uncertainty of the available dose-response data from epidemiological studies and laboratory animal studies. US EPA (2002) also concluded that their health assessment only applied to the exhaust from diesel engines manufactured before 1995, and that the exhaust from newer engines would need a separate evaluation. 19 The DE health effects literature has continued to evolve since the preparation of these DE hazard assessments, prompting Navistar to conduct its critical reassessments. Hesterberg et al. (2006) concluded that the DE epidemiological data remain insufficient for quantitatively linking DE exposure levels to lung cancer risk. Hesterberg et al. (2006) highlights observations of elevated lung cancer incidence among truck drivers prior to dieselization, the lack of increased lung cancer risk among underground miners despite diesel exposures several times higher than those of railroad workers or truck drivers, the overall lack of dose-response among DE-exposed populations, and persisting limitations in the exposure data and control of confounding in the DE epidemiological studies. The real-world implications of findings of short-term lung and systemic inflammatory responses and cardiovascular health responses in some recent DE human clinical studies remains uncertain given the use of older diesel engines and DE exposure concentrations well in excess of typical ambient or even occupational levels (Hesterberg et al., 2009). In contrast to the widespread public notion of DE health risks, the scientific evidence remains far from clear. A more recently emerged concern is for potential health effects of very small particles. Hesterberg et al. (2010) assessed the health implications of the large numbers of nano-sized particles (i.e., particles with diameters smaller than 100 nm, also commonly referred to as either ultrafine particles or nanoparticles) present in DE, concluding that health data from DE human clinical studies do not support any unique toxicities of nano-sized diesel particles compared to other small particles. It should be noted that nano-sized particles are not unique to diesel and indeed are produced in larger numbers by gasoline and CNG engines. 20 Hesterberg et al. (2011) examined the emerging body of studies supporting the low human health hazard potential of NTDE from post-2006 advanced diesel engines. The significant advances to diesel engine technology and the major changes in the composition of diesel fuel and engine lubricants required to meet the 2007 and 2010 emissions requirements have resulted in a highly different type of diesel exhaust. Termed "New Technology Diesel Exhaust," or NTDE (Hesterberg et al., 2006, 2008, 2011), there is now a substantial body of data showing that it is strikingly different in chemical and physical properties from DE emitted by pre-1988 (i.e., preregulation) diesel engines (referred to as Traditional Diesel Exhaust, or TDE). For example, relying upon emissions data from 25 reports on transit buses, school buses, refuse trucks, and passenger cars, Hesterberg et al. (2008) documented substantial reductions in the levels of PM, carbon monoxide, total hydrocarbons, non-methane hydrocarbons, formaldehyde, benzene, acetaldehyde, and polycyclic aromatic hydrocarbons (PAHs) in NTDE. Due in large part to the high removal efficiencies of the catalyzed diesel particulate filters (c-DPFs) that have gained widespread usage as integral components of new technology aftertreatment systems, consistent PM mass reductions of >90% have been observed for post-2006 engines in a number of studies (Hesterberg et al., 2008, 2011). PAHs are often highlighted as being among the more toxic DE constituents, but recent data support >90% reductions in emissions of most PAH and nitro-PAH species (Hesterberg et al., 2008, 2011). As discussed in Hesterberg et al. (2011), there is a growing body of data showing the greater resemblance of DEP in NTDE to particulate emissions from compressed natural gas (CNG) or gasoline engines than from TDE. Preliminary toxicological data are now available indicating that these emissions changes translate into risk reductions, with both human and animal studies of NTDE exposures reporting an absence of biological responses previously reported in prior studies of older diesel engine technologies 21 (Hesterberg et al., 2011). Although the available toxicological data is inadequate to conduct a reliable hazard assessment for NTDE, Hesterberg et al. (2011) concluded that "there is now sufficient evidence to conclude that health effects studies of pre-2007 TDE likely have little relevance in assessing the potential health risks of NTDE exposures." As discussed in detail below, Navistar has been highly active in promoting the need for comprehensive toxicological studies of NTDE to better understand the changes to its hazard profile. Development and Support of Proactive Diesel Health Effects Research Initiatives In addition to evaluating existing data, Navistar has also implemented a proactive approach to understanding potential diesel health risks that focuses on the formulation of new research strategies and the reduction of data gaps and uncertainties in the health effects literature. As prominent examples of this proactive approach, Navistar has worked to develop and sponsor state-of-the-art research initiatives, including the Advanced Collaborative Emissions Study (ACES) of the emissions and toxicology of new technology diesel engines meeting the 2007/2010 emissions standards (discussed below) and studies quantifying in-cabin DE exposures aboard school buses (for more information, see Iverson et al., 2004, 2011; Liu et al., 2010). As early as 2002, Navistar began working on a proactive research initiative designed to assess the potential health effects of the new low-emitting diesel engine technologies that it had helped develop. In 2004, these efforts culminated in the finalization of the comprehensive ACES research program, which included both emissions characterization and speciation/toxicity studies of prototype 2007-2010 engine technologies. As an advisor to the Health Effect Institute's (HEI) ACES Research Committee, Navistar helped develop the research program for the $20 million study and build consensus among multiple stakeholders (which include US EPA, the Engine 22 Manufacturers Association, the California Air Resources Board, the American Petroleum Institute, the Department of Energy, and the National Resources Defense Council (NRDC)). Navistar is a member of the ACES Advisory Committee, providing expert advice and oversight for this study. Corporate Environmental Legacies Navistar has operated numerous manufacturing facilities around the world and, at times, has employed more than 100,000 employees. For many years, the business model was one of vertical integration which included coal and iron ore mines, timber tracts, and steel mills. As business conditions and models changed over time in response to technology, competition and economic conditions, many operations were consolidated, sold or closed. Some of these operations have produced significant environmental liabilities, such as from asbestos remediation. Navistar along with several other companies has also been linked to some third party sites that have become US EPA Superfund sites. Navistar’s approach to these environmental legacies has been to actively manage the sites and prepare them for productive reuse as Brownfield sites, oftentimes working closely and voluntarily with local communities. For example, approximately 85 percent of the Wisconsin Steel Works site that was formerly owned by Navistar has now been completely remediated, with 131 acres of this 176-acre site in southeastern Chicago now being redeveloped into a new liquid asphalt plant (Navistar, 2011). This plant, which is being built in an environmentally sustainable manner, is expected to help revitalize this community through job creation. Navistar's remediation efforts at the former West Pullman Works site in Chicago have 23 culminated in this site having the largest urban solar plant in the US, with generation of enough clean electricity to power up to 1,500 homes. It is useful to note that some aspects of current environmental liability were once viewed quite differently. For example, although sustainability was not a common term during the period of extensive asbestos use, asbestos insulation was viewed as a sustainable building feature for its fire protection and heat conservation properties. A sustainable company must be prepared to adapt to changes in information, and if necessary, to correct mistakes of the past no matter how well informed and well intentioned at the time. Employee Legacies As a result of severe economic challenges in the 1980s, several plants were closed and business units sold. The employee population dropped from more than 100,000 globally to less than 12,000, mainly in the U.S. However, employee benefit obligations for closed operations and for many of the sold operations remained with the company. As a result, the number of retirees with pension and health care benefits exceeded the number of active employees by a factor of four. As health care costs have continued to rise sharply in the last three decades, the challenge of managing these retiree costs has increased. The US accounting rules have changed the way that post-retirement benefit obligations are treated on balance sheets, requiring recognition of all future commitments as liabilities. As a result, many companies regard such benefits as non-sustainable and have cut them back or eliminated them altogether. Some large companies who have reorganized under Chapter 11 of 24 the United States Bankruptcy Code have abandoned retiree health care benefits and transferred pension obligations to the government-sponsored Pension Benefit Guarantee Corporation, which administers plans at reduced rates. Navistar has changed some aspects of its benefit programs for current employees, such as moving from defined benefit to defined contribution plans which receive more favorable accounting treatment. However, for its legacy commitments, Navistar has chosen to manage rather than abandon them. When accounting rule changes threatened to undermine the viability of the company by creating newly recognized health care liabilities that would have exceeded total company assets, Navistar developed a creative solution. Navistar initiated a novel legal proceeding that resulted in the formation of a trust in 1993 to manage health care benefits and preserve company financial viability. Some change of benefits was necessary, such as introduction of premiums and copayments to provide incentives for cost control and improved usage. The trust continues to provide health care, vision, and dental benefits to current and future retirees who started with the company before 1993. Navistar continues to provide health, vision and dental benefits for all active employees, including those not part of the trust agreement. Summary and Conclusions: Broader Definition of a Sustainability Program Veltri (1991) defines three stages of management that companies experience in implementing sustainability programs. The first stage is focused on compliance, where companies are reluctant go beyond the minimum required to meet any regulatory requirements or societal expectations. 25 In the second stage, companies seek to follow the example of leaders in the field. In the third stage, companies integrate sustainability into their own unique business cultures, ultimately using it as a competitive business advantage. By embracing the concept of sustainability in its broadest sense and approaching it as "a long-term, continuously advancing process that keeps improving the outcome for us now and for the future" (Navistar, 2008a), Navistar’s evolving sustainability program seeks to attain this third stage. Navistar's sustainability model addresses the recognized pillars of environmental, social, and economic sustainability, sharing some of the emerging commonalities of today's modern corporate sustainability programs, including senior management positions charged with leading corporate sustainability efforts, annual sustainability reports that provide standardized reporting metrics, and third-party accreditation (e.g., ISO 14001). Furthermore, as demonstrated in this paper, Navistar has also shaped its sustainability model in response to its unique operating environment and significant business challenges, incorporating sustainable innovation, product stewardship, and management of legacy issues as core components. Navistar has utilized basic research and sound science to help these components become keys to both Navistar's sustainability model and its business success. With its commitments to sustainable innovation, product stewardship, and management of legacy issues, Navistar's sustainability model yields a variety of benefits that may not be reflected in standard sustainability criteria that include energy usage, water usage, waste generation, recycling, and greenhouse gas emissions. For example, although health care and retirement benefits are significant economic concerns and would seem to represent important societal responsibilities, GRI criteria do not include reporting on pension and health care issues. 26 Consumers who purchase and use innovative Navistar products, such as advanced technology diesel engines that reflect both reduced emissions and improved energy efficiency, are realizing sustainability gains rather than Navistar. Nevertheless, rather than solely addressing a standard set of sustainability criteria, Navistar has continued to shape its sustainability model in response to its unique operating environment and business challenges, achieving consistent business success in the process. Although companies should define their own sustainability models based on such businessspecific factors as products or services, business models and cultures, and stakeholder interests, Navistar's sustainability model provides a blueprint that can be utilized by others looking for frameworks upon which to construct a successful sustainability model. It demonstrates how sustainable innovation, product stewardship, and management of legacy issues can contribute to a successful sustainability model. Moreover, Navistar's sustainability model continues to evolve, as new targets are continuously established, including increasingly more ambitious energy reduction and greenhouse gas reduction goals (Ardiente, 2010). Authors' Disclosure The authors of this paper are either employed by Navistar or are consultants to Navistar. All authors declare no other financial interest in the subject matter of this study. References Adams WM. 2006. The Future of Sustainability, Re-thinking Environment and Development in the Twenty-first Century. In IUCN Renowned Thinkers Meeting, January 29-31. 27 Ardiente EM. 2010. Climate Change and Sustainability at Navistar. Presented at the 15 th IUAPPA World Clean Air Congress, September 16. Belu C. 2009. Ranking corporations based on sustainable and socially responsible practices. A data envelopment analysis (DEA) approach. Sustainable Development 17 : 257-268. CA Rich Consultants, Inc. 2005. Letter Report to J. Dyber (NYSDEC) re: Monthly Progress Report February 2005, Utility Manufacturing Co. Site, 700 Main Street, Westbury, NY, Site ID No.: 130043H. SAD 047512. California Environmental Protection Agency (Cal EPA). 1998. For the "Proposed Identification of Diesel Exhaust as a Toxic Air Contaminant." Part B: Health Risk Assessment for Diesel Exhaust. Office of Environmental Health Hazard Assessment: Sacramento, CA. Cowan DM, Dopart P, Ferracini T, Sahmel J, Merryman K, Gaffney S, Paustenbach DJ. 2010. A crosssectional analysis of reported corporate environmental sustainability practices. Regulatory Toxicology and Pharmacology 58 : 524-538 . DOI :10.1016/j.yrtph.2010.09.004 Global Reporting Initiative (GRI). 2006. RG - Sustainability Reporting Guidelines. Version 3.0. http://www.globalreporting.org/ReportingFramework/ReportingFrameworkDownloads/G3GuidelinesIndi vidualDownloads.htm [7 October 2010] Global Reporting Initiative (GRI). 2010. History of GRI. http://www.globalreporting.org/AboutGRI/ WhatIsGRI/History/OurHistory.htm Greenbaum D, Mauderly J, MacDonald J, Tennant C, Shaikh R, Costantini M, van Erp A. 2010. The Advanced Collaborative Emissions Study (ACES): Phase 3. http://www1.eere.energy.gov/ vehiclesandfuels/pdfs/deer_2010/thursday/presentations/deer10_greenbaum.pdf Harrison EB, 2008. Navistar is among companies benchmarked for advancing sustainability missions and public policy goals. Corporate Greening 2.0: Create and Communicate Your Company's Sustainabilty Strategies, Exeter, NH, PublishingWorks, ISBN 1-933002-70-0, p. 203. Harrison EB, 2009. Paper introducing the concept of Corporate Greening as a sustainable corporation and business strategy; the paper explores models for corporate officers to follow in developing green sustainability strategies. Paper first presented at 2008 Corporate Communications Institute, London; peerreviewed and published in Corporate Communications, An International Journal Volume 14, Number 3, p. 280 et seq. Health Effects Institute (HEI). 2010. ACES health testing under way. HEI Update Winter 2010-2011 : 6. Health Effects Institute, Coordinating Research Council. 2006. The Advanced Collaborative Emissions Study (ACES) Project Plan for Emission Characterization and Health Effects Assessment. Health Effects Institute: Boston, MA, Coordinating Research Council: Alpharetta, GA. Hesterberg TW, Bunn WB, Chase GR, Valberg PA, Slavin TJ, Lapin CA, Hart GA. 2006. A critical assessment of studies on the carcinogenic potential of diesel exhaust. Critical Reviews in Toxicology 36 : 727-776. Hesterberg TW, Bunn WB, McClellan RO, Hart GA, Lapin CA. 2005. Carcinogenicity studies of diesel engine exhausts in laboratory animals: A review of past studies and a discussion of future research needs. Critical Reviews in Toxicology 35 : 379-411. Hesterberg TW, Lapin CA, Bunn WB. 2008. A comparison of emissions from vehicles fueled with diesel or compressed natural gas. Environmental Science & Technology 42 : 6437-6445. 28 Hesterberg TW, Long CM, Bunn WB, Sax SN, Lapin CA, Valberg PA. 2009. Non-cancer health effects of diesel exhaust: A critical assessment of recent human and animal toxicological literature. Critical Reviews in Toxicology 39 : 195-227. Hesterberg TW, Long CM, Lapin CA, Hamade AK, Valberg PA. 2010. Diesel exhaust particulate (DEP) and nanoparticle (NP) exposures: What do DEP human clinical studies tell us about potential human health hazards of nanoparticles? Inhalation Toxicology 22 : 679-694. Hesterberg TW, Long CM, Sax SN, Lapin CA, McClellan RO, Bunn WB, Valberg PA. 2011. Particulate matter in new technology diesel exhaust (NTDE) is quantitatively and qualitatively very different from that found in traditional diesel exhaust (TDE). Journal of the Air and Waste Management Association in press. Hunnicutt D. 2003. Well Workplace Award Executive Summary. International Truck and Engine Corporation. http://www.welcoa.org/wellworkplace/pdf/il_international_truck.pdf IARC. 1989. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Volume 46: Diesel and Gasoline Engine Exhausts and Some Nitroarenes. IARC Monograph No. 46. International Agency for Research on Cancer: Lyon, France. Ireson RG, Easter MD, Lakin ML, Ondov JM, Clark NN, Wright DB. 2004. Estimation of diesel particulate matter concentrations in a school bus using a fuel-based tracer – A sensitive and specific method for quantifying vehicle contributions. In Transportation Research Record, No. 1880. Transportation Research Board of the National Academies; 21-28. Ireson RG, Ondov JM, Zielinska B, Weaver CS, Easter MD, Lawson DR, Hesterberg TW, Davey ME, Liu L-JS. 2011. Measuring in-cabin school bus tailpipe and crankcase PM2.5: A new dual tracer method. Journal of the Air and Waste Management Association 61 : 494-503. ISO. 2004. ISO 14001:2004: Environmental management systems – Requirements with guidance for use. http://www.iso.org/iso/catalogue_detail?csnumber=31807 ISO. 2010. Certification. http://www.iso.org/iso/iso_catalogue/management_and_leadership_standards/ certification.htm Kates RW, Parris TM, Leiserowitz AA. 2005. What is sustainable development? Goals, indicators, values, and practice. Environment 47 :8-21. Khalek IA, Bougher TL, Merritt PM, Zielinska B. 2011. Regulated and unregulated emissions from highway heavy-duty diesel engines complying with U.S. Environmental Protection Agency 2007 emissions standards. Journal of the Air and Waste Management Association 61 : 427-442. Khalek IA, Bougher TL, Merritt PM. 2009. Phase 1 of the Advanced Collaborative Emissions Study, Final Report. SwRI® Project No. 03.13062. Lawrence Livermore National Library (LLNL). 2010. Lawrence Livermore National Lab, Navistar work to increase semi-truck fuel efficiency. NR-10-02-08. February 16. Liu L-JS, Phuleria HC, Webber W, Davey M, Lawson DR, Ireson RG, Zielinska B, Ondov JM, Weaver CS, Lapin CA, Easter M, Hesterberg TW, Larson T. 2010. Quantification of self pollution from two diesel school buses using three independent methods. Atmospheric Environment 44 : 3422-3431. doi:10.1016/j.atmosenv.2010.06.005 Maricq MM. 2007. Chemical characterization of particulate emissions from diesel engines: A review. Aerosol Science 38 : 1079-1118. doi:10.1016/j.jaerosci.2007.08.001 Marshall JD, Toffel MW. 2005. Framing the elusive concept of sustainability: A sustainability hierarchy. Environmental Science & Technology 39 : 673-682. DOI: 10.1021/es040394k 29 National Institute for Occupational Safety and Health (NIOSH). 1988. Carcinogenic Effects of Exposure to Diesel Exhaust. NIOSH Current Intelligence Bulletin 50. National Toxicology Program (NTP). 2000. Report on Carcinogens. Ninth Edition. U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program. Navistar. 2007a. Sustainability 2007: Report on Navistar's Commitment to Environmental, Social and Economic Innovation. http://www.navistar.com/StaticFiles/navistardotcom/pdf/ Sustainability/Navistar%20Sustainability%202007.pdf Navistar. 2007b. Navistar News. http://media.navistar.com/index.php?s=43&item=39 [3 April 2007] Navistar. 2008a. Sustainability 2008: A Report on Our Global Commitment to Environmental, Social and Economic Innovation. http://www.navistar.com/crpdf/Sustainability2008Report.pdf Navistar. 2008b. International LoneStar earns EPA SmartWay certification for fuel efficiency, emissions reduction. http://media.navistar.com/index.php?s=43&item=159 [25 June 2008] Navistar. 2009a. Sustainability 2009: A Report on Our Global Commitment to Environmental, Social and Economic Innovation. http://www.pageturnpro.com/Olver-Dunlop-Associates/17146-NavistarSustainability2009/index.html#1 Navistar. 2009b. Navistar and Modec sign joint venture to produce and market all-electric truck. http://media.navistar.com/index.php?s=43&item=336 [2 December 2009] Navistar. 2010a. Navistar selected as partner in development http://media.navistar.com/index.php?s=43&item=347 [12 January 2010] of DOE "Super Truck". Navistar. 2010b. ISO 14001:2004 certified locations. http://www.navistar.com/ Navistar/Inside+Navistar/Sustainability/Recognition+%26+Certification/ISO+14001+Certification Navistar. 2011. Sustainability 2010: Navistar's Commitment to Sustainability…in People, Products and Operations. http://www.pageturnpro.com/Olver-Dunlop-Associates/28505-Navistar-2010-SustainabilityReport/index.html#1 Satterfield MB, Kolb CE, Peoples R, Adams GL, Schuster DS, Ramsey HC, Stechel E, Wood-Black F, Garant RJ, Abraham MA. 2009. Overcoming nontechnical barriers to the implementation of sustainable solutions in industry. Environmental Science & Technology 43 : 4221-4226. United Nations (UN). 1992. Report of the United Nations Conference on Environment and Development. Annex I: Rio Declaration on Environment and Development. Volume I. A/CONF.151/26 (Vol. I) In United Nations Conference on Environment and Development, Rio de Janeiro, June 3-14, 1992. United Nations (UN). 2002. Report of the World Summit on Sustainable Development. A/CONF.199/20. Johannesburg, South Africa, 26 August - 4 September. US Environmental Protection Agency (US EPA). 2002. Health Assessment Document for Diesel Engine Exhaust. EPA/600/8-90/057F, National Center for Environmental Assessment, Office of Research and Development. World Commission on Environment and Development (UN WCED). 1987. Our Common Future. Oxford University Press: Oxford, UK. 30 Figure Captions Figure 1. The three components of sustainability. As initially envisioned, these components should have equal weight, and where they overlap represents sustainability or sustainable development (UN, 2002). However, all too often, the reality is that they are often not so well balanced (Adams, 2006). Figure 2. Annual releases for Navistar U.S. facilities reported to US EPA's Toxics Release Inventory (TRI). Shows the amount of chemicals and chemical categories reportable under the Emergency Planning & Community Right-to-Know Act (EPCRA) released or recycled off site from Navistar's U.S. manufacturing locations. From Navistar (2011). Figure 3. Trends in Navistar health care costs compared to the national average: 1999 to 2010 (estimated). Figure 4. Timeline of recent Navistar accomplishments related to sustainable innovation (information from Navistar, 2007a, 2008a, 2009a, 2011). Figure 5. Reductions in the US EPA standards for particulate matter (Panel A) and nitrogen oxide (NOx) (Panel B) emissions from heavy-duty diesel trucks (t) or urban buses (ub), relative to pre-1988 emissions. Reproduced with permission from Hesterberg et al. (2006). 31 Economic Social Environmental The Theory Economic Social Environmental In Practice 32 33 Health Care Cost Trend Per Employee/Retiree 15.00% 10.00% 5.00% 0.00% 1999-2002 2003 2004 2005 2006 2007 Navistar National Average -5.00% -10.00% -15.00% 34 2008 2009 2010 35 Fig. 1. Reductions in Diesel Particulate Matter Emissions in the US US EPA standards for particulate emissions from heavy duty diesel trucks (t) or urban buses (ub), calculated as grams particulate matter emitted per brake-horsepower-hour (g/b hp-hr) and adjusted relative to pre-1988 unregulated engine emissions. From: US EPA Health Assessment Document for Diesel Panel A Engine Exhaust, May 2002. Table 2-4, P. 2-16. Particulates Emissions, g/bhp-hr (relative to unregulated) 100% 60% 25% 10% 5% Unregulated 1988 t 1991 t 1994 t 1996 ub 1% 2007 t Fig. 2. Reductions in Diesel Nitrogen Oxide (NO x) Emissions in the US US EPA standards Traditional for NOx emissions from heavy duty diesel as grams NOx Diesel Transitional Dieselengines, calculated New Technology emitted per brake-horsepower-hour (g/b hp-hr). From: USEPA Health Assessment Document for Exhaust (TDE) Exhaust Diesel Exhaust (NTDE) Diesel Engine Exhaust, May 2002, Table 2-4, p. 2-16. Panel B NOx (g/bhp-hr) 15 6 5 4 2 0.2 1977 1990 1991 1998 Model Year 36 2004 2010