HAZARD COMMUNICATION
Hazard Communication Standard
The right-to know movement was precipitated by OSHA in the 1983 with the promulgation of
the Hazard Communication Standard (HCS) 29.CFR1910.1200. The basic principle of HCS is
that informed workers are less likely to be injured by chemical and chemical processes than the
uninformed workers. The purpose of the HCS is to ensure that the information of hazard
associated with handling, transport and storage of chemicals, are evaluated and transmitted to
relevant individuals or parties; chemical manufacturers, transporters and users1.
Through the Hazard Communication Standard, OSHA requires chemical manufacturer or
importer to2:
1. Analyze and assess all hazards of the chemicals produced or imported.
2. Document associated hazards and develop written warning labels/information and
material safety data sheet (MSDS).
3. Address the hazard information to the individuals working with the chemicals.
4. Label, tag and attach warning documentation of chemicals leaving the workplace.
A required component in the program is a list of hazardous chemicals known to be
present in the workplace. MSDS of the chemicals should also be available to employee. If
the substance was purchased before the right to know era and no MSDS is on hand, the
employer is required to obtain or generate one. Some good sources for MSDS
information are current manufacturer /distributor of the chemicals or state consultant
agency.
1
Thomas, C.E, Process Technology Safety, Health, and Environment Second Edition, Thomson
Delmar Learning, 2005.
2
Asfahl, C.R, Industrial Safety and Health Management Fifth Edition, Prentice Hall 2003.
Ways of addressing the hazards and means of protection from the hazards are to be
accomplished by comprehensive hazard communication programs such as written forms
of warnings and training.
Written hazard communication program for the workplace is developed through lists of
hazardous chemicals present, labeling of containers of chemicals in the workplace, as
well as of containers of chemicals being shipped to other workplaces, preparation and
distribution of material safety data sheets to employees and downstream employers.
OSHA also place responsibility of hazard communication to employers and requires employers
to address the following:
1. Preparing a written Hazard Communication program.
2. Organizing hazardous chemical inventory list.
3. Designing MSDSs.
The written hazard communication program should be designed so every new employees are
informed upon initial assignment and existing employees maintain high alert of the hazards. The
content of the written program should also be site-specific, readily accessible by plant personnel,
and being updated accordingly.
Training on hazard communication program should be provided as well to inform the physical
and chemical hazards due to the chemicals substances to the workers, to guide workers on how
to detect release of hazardous chemicals, how to read an MSDS, how to select and use PPE and
how to understand the standard labeling systems, Department of Transportation (DOT), National
Fire Protection Association (NFPA) and Hazardous Materials Identification System (HMIS).
In addition, the regulation also requires distributors to transfer the required information to
employers. Employers who do not produce or import chemicals need only focus on those parts of
this rule that deal with establishing a workplace program and communicating information to their
workers. Appendix E of the regulation is a general guide for such employers to help them
determine their compliance obligations under the rule. In the workplace the employer shall
maintain copies of the required material safety data sheets for each hazardous chemical, and shall
ensure that they are readily accessible during each work shift to employees when they are in their
work area. Electronic access, microfiche, and other alternatives to maintaining paper copies of
the material safety data sheets are permitted as long as no barriers to immediate employee access
in each workplace are created by such options.3
The Hazard Communication program built by the safety division should set up information
system that trace the identity, location of use, and time of use for hazardous substances along
with each employee exposure for a retention period of at least 30 years. Employee medical
record must be preserved and maintained for the duration of employment plus 30 years. The
reason of very long retention period is to permit tracing the cause of illnesses that may have
extreme long latency periods after exposure to hazardous substances.
The Hazard Communication program also concerns on the record retention of hazardous
chemicals. Sale of the business does not relieve the employer to the record-retention
responsibility because upon sale the successor of the company is required to receive and
maintain the record. If the business is closed permanently, the employer may be required to
transfer the record to NIOSH, depending on the specific standards pertaining to the hazardous
substance.
Sources of reference in implementation of hazard communication standard can be accessed in
many ways. Protocol guides such as AIHA protocol guide on hazard communication established
in 1995 is readily available and can be used as reference.
Chemical and Physical Properties of Product
Comprehensive information on all the chemicals involved in the process starting from raw
materials, intermediates and final products, is necessary in order to prepare precaution of the
hazards these chemicals imposed due to its properties. A list of some important physical and
chemical properties of any chemical is given in Table X. These properties are very helpful in
identifying certain protection measure against hazards that may be present during the handling of
hazardous chemicals.
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Reactivity, instability and explosive properties and information on the physical and chemical
properties of chemicals and on the associated hazards and the appropriate precautions cast in
standard format is available in the form of MSDSs.
Table X. Important physical and chemical properties of a chemical4
•
Molecular structure
•
Freezing point, vapor pressure, boiling point
•
Critical pressure, temperature, volume
•
Vapor density, specific heat, viscosity, thermal conductivity
•
Liquid density, specific heat, viscosity, thermal conductivity
•
Latent heats of vaporization and fusion
•
Dielectric constant, electrical conductivity
•
Flammability limits
•
Flash point
•
Autoignition temperature
•
Minimum ignition energy
•
Maximum experimental safe gap
•
Self-heating
•
Corrosiveness to materials of construction
•
Incompatibility with particular materials
Polymerization,
•
Polymerization characteristics
Decomposition
•
Decomposition, hydrolysis characteristics
Impurities
•
Impurities in:
General properties
Flammability
Corrosion
raw material
plant material
Reaction,
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•
Mutual solubility with water
•
Heats of formation, combustion, decomposition
Lee’s Loss Prevention in The Process Industries Vol.1, Vol.2 and Vol.3 Hazard Identification,
Assessment and Control. 3rd Edition. Elsevier. 2004.
Explosion
Toxicity
Radioactivity
•
Energy hazard potential
•
Thermal stability
•
Impact sensitivity
•
Threshold limit values, emergency exposure limits
•
Lethal concentration LC50, lethal dose LD50
•
Exposure effects (inhalation, ingestion, skin and eye contact)
•
Long-term low exposure effects
•
Warning levels (smell)
•
Radiation survey
•
α-particle, β- , γ- ray exposures
Hazards and Exposure Limits
The degree of hazard of a chemical is determined by its physical and chemical properties and the
magnitude or dose of those properties. In some cases, even the least hazardous materials such as
water may be toxic to human if consumed overdose. Exposure limits of chemicals substances are
designed to allow process technician to work safely with a certain chemical over a period of
time.
The poison is in the dosage not the chemical
The limits are represented by numerical values and available from four different exposure limits:
a. Threshold Limit Values (TLV)
TLV for a large number of chemical agents were established by the American
Conference on Governmental Industrial Hygienists (ACGIH). Threshold dose is the
lowest value on the response versus dose curve, where below this dose the body is able to
detoxify and eliminate the agent without any detectable effects. The TLVs refer to
airborne concentration corresponds to the condition under which no adverse effects are
normally expected during a workers’ lifetime.
There are three types of TLVs; time-weighted average (TLV-TWA), short-term exposure
limit (TLV-STEL) and ceiling or maximum limit exposure (TLV-C). Assumptions used
in the TLV method is that the exposure occurs only during normal working hours, eight
hours per day and five days per week. TLV is also known as the Maximum Allowable
Concentration (MAC). TLVs calculation uses part per million (ppm) by volume,
milligrams of vapor per cubic meter of air (mg/m3) and specifically for dust, millions of
particles per cubic foot of air (mppcf).
b. Permissible Exposure Limits (PEL) – OSHA mandated regulatory limits
Permissible exposure level (PEL) is OSHA defined threshold dose which also follows the
TLV-TWA of ACGIH. However, the differences between PEL and TLV lie in the
number of chemical covered and the frequency of update, whereas PEL has less number
in both category, and that TLVs value are more conservative than PEL.
c. Occupational Exposure Limits (OELs)
OELs are developed by OSHA and industrial hygiene for chemical substance that does
not have TLVs information.
d. Suppliers recommended limits
Another exposure limit that is important to know is the Immediately Dangerous to Life and
Health (IDLH). IDLH is another quantity threshold frequently reported, where exposure to
this quantity and above would cause severe damage to health and even death.
Material Safety Data Sheet (MSDS)
With regard to the right-to-know requirements, for any hazardous chemical that attracts the
requirement for a Material Safety Data Sheet (MSDS) under the OSHA 1970, the facility has to
submit either the data sheets or a list of the chemicals to the local emergency planning
committee, the state Emergency Response Center and the responsible fire department. The
facility must also submit to the same three bodies information on the hazardous inventory.5 The
OSHA act also discuss about requirement to submit information on the ‘toxic chemical release
emission inventory’, or Toxic Release Inventory (TRI), on the Toxic Chemical Release Form.
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The data required in this form are concerned primarily with passage of toxic chemicals into the
environment. For each chemical, a mass balance and the quantity emitted annually is required.
Safety data sheet compilations are prepared by various organizations and are available on the
internet. An EC Directive (91/155/EEC) lays down the contents of a safety data sheet. In the
United Kingdom, this is implemented by the Chemical Hazard Information and Packaging
(CHIP) Regulations. HSE guidance: Safety Data Sheets for Substances and p reparations
Dangerous for Supply (1993) has been amended on a regular basis since its inception and further
guidance is available in The EC Safety Data Sheet Directive by CONCAWE (1992 92/55). Other
sources include those by the NFPA (NFPA 704) and the NIOSH6. The directive requires that the
contents of a safety data sheet cover:
1. Identification of the substance/preparation and company
2. Composition/information on ingredients
3. Hazards identification
4. First-aid measures
5. Firefighting measures
6. Accidental release measures
7. Handling and storage
8. Exposure controls/personal protection
9. Physical and chemical properties
10. Stability and reactivity
11. Toxicological information
12. Ecological information
13. Disposal considerations
14. Transport information
15. Regulatory information
16. Other information.
Both the guides mentioned give detailed guidance on the material to be included under each of
these heads. It is the responsibility of the supplier of a chemical to supply the safety data sheet.
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Sensitive issue on MSDS is trade secret which is addressed in details by OSHA standard. With
proper justification, industries have the right to withhold specific chemical identities from
MSDS. Nevertheless, if required the specific chemical identities should be disclosed in criteria
specified in the standard. In non-emergency situation, the manufacturer or importer may ask for
confidentiality agreement.7
In Figure X, MSDS of acetic acid is given as an example.
Hazardous Materials Identification System - NFPA Rating System
The widely used chemical labeling system was originally intended to provide basic information
to fire fighting, emergency, and other personnel, enabling them to more easily decide whether to
evacuate the area or to commence emergency control procedures. It was also intended to provide
them with information to assist in selecting fire fighting tactics and emergency procedures.8
The National Fire Protection Association (NFPA) hazard rating system uses a diamond-shaped
diagram symbols and numbers to indicate the degree of hazard associated with a particular
chemical. The diamond symbol is placed on containers or MSDSs to identify the degree of
hazards of the chemical. The diagram has three color-coded hazard categories, which are fire
hazard, reactivity and health. Each category has rating numbers of hazardous level, which
increases as the hazard level of the chemical increases. The last part of the diamond section is for
other specific hazard associated with that particular chemical.
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http://safety.science.tamu.edu/nfpa.html
Figure X. NFPA diamond symbol*
The four categories of NFPA rating are explained in the following9:
HEALTH
The degree of health hazard of a chemical or material is based on the form or condition of the
material, as well as its inherent properties. The degree of health hazard of a material should
indicate the degree of personal protective equipment required for working safety with the
material.
1 indicates slightly toxic material which requires only minimal protection (e.g. safety
glasses and gloves).
2 indicates moderately toxic material which requires more rigorous PPE or protection
system (e.g. chemical goggles, lab/work smock, local ventilation) in addition to that
required for less toxic material.
3 or 4 indicate highly to extremely toxic or deadly materials such as carcinogen, mutagen, or
teratogen materials. These materials will require specific PPE and equipment
protection system (e.g. respirator or exhaust hood, full face shield, rubber apron,
9
http://www.sefsc.noaa.gov/HTMLdocs/nfpahazard.htm
specialized glove, handling tongs, etc) beyond that required for moderately toxic
material.
The selection of specific PPE is determined using MSDS and/or other safety information.
FLAMMABILITY/FIRE HAZARD
The flammability or fire hazard is strongly related with the degree of ease of the material to
ignite and burn. The physical state of the materials, as well as the properties, affects the extent
of the hazard. Many hazardous materials such as acetone and gasoline have a flash point far
below freezing and will readily ignite with a spark if the vapor concentration is sufficient.
1 indicates materials with a flash point > 200°F.
2 indicates materials with a flash point between 100°F- 200°F.
3 indicates materials with a flash point between 73°F-100°F.
4 indicates materials with a flash point < 73°F.
REACTIVITY
The reactivity hazards indicate the potential of energy release of a material or chemical. Some
materials are capable of rapid energy release without any catalyst, while others can undergo
violent eruptive or explosive reactions if they come in contact with water or other materials. The
rating is used to indicate the potential to react if the material is heated, jarred, or shocked.
1 indicates a material that may be reactive if heated and one that reacts with water.
2 indicates a material that may react violently without detonation.
3 indicates a material that may detonate or explode if subjected to a strong initiating force
or heating under confinement.
4 indicates a material that readily detonates or explodes.
SPECIFIC HAZARD - This information may include the chemical or material's radioactivity,
proper fire extinguishing agent, skin hazard, and its use in pressurized containers, protective
equipment required, or unusual reactivity with water. Other hazardous properties which is
OX or OXY indicates a material that is an oxidizer.
W or W indicates a material that is water reactive.
ALK indicates a material that is alkali.
COR indicates a material that is corrosive.
RAD indicates a material that is radioactive.