Application code:
Application Type
Applicant:
Purpose of the Application
Date application received:
Consideration Date
Considered by
2 July 2008
HSR08017
To import or manufacture any hazardous substance under Section 28A(2)(b) of the Hazardous Substances and New Organisms Act 1996.
Southwell Products Ltd
To import or manufacture Chlorine Dioxide as a broad spectrum fungicide for use on field crops. (low hazard)
15 May 2008
2 July 2008
Rob Forlong (Chief Executive, ERMA New Zealand)
1
1.1
The application to import or manufacture the proposed substance for release is approved with the controls as set out in Appendix 1. This approval has been given in accordance with the relevant provisions of the Hazardous Substances and New Organisms Act 1996 (“the Act”), the relevant HSNO Regulations, and the HSNO (Methodology) Order 1998 (“the Methodology”), based on the proposed substance being formulated so that the substance has one or more hazardous properties and each hazardous property has the least degree of hazard for that property.
1.2
The proposed substance has been given the following unique identifier for the
ERMA New Zealand Hazardous Substances Register:
Chlorine Dioxide in Aqueous Solution
2
2.1
Unless otherwise stated, references to section numbers in this decision refer to sections of the Act. The application was lodged pursuant to section 28. The decision was determined in accordance with section 28A(2)(b), taking into account the requirements of that section and matters specified under Part II of the Act.
2.2
Unless otherwise stated, references to clauses in this decision refer to clauses of the Methodology. Consideration of the application followed the relevant provisions of the Methodology.

3
3.1
The purpose of this application is to gain approval to import or manufacture
Chlorine Dioxide in Aqueous Solution as a fungicide.
3.2
The application was formally received on 15 May 2008.
3.2.1
The application timeframe was extended by three working days due to an information request made under section 52.
3.2.2
The consideration of the application was postponed by 20 working days under section 58(1).
3.3
The Agricultural Compounds & Veterinary Medicines Group (ACVMG) of the
New Zealand Food Safety Authority (NZFSA), the Department of Conservation and the Department of Labour Workplace Group were advised of the application (clause 2(2)(e)).
3.3.1
No responses were received.
3.4
Evaluation of the application was undertaken by the ERMA New Zealand project team which comprised the following staff members:
Margaret Keane
Cora Drijver
Peter Dawson
Advisor (Hazardous Substances)
Advisor (Hazardous Substances)
Principal Scientist (Hazardous Substances)
3.5
The application was considered by the Chief Executive of ERMA New Zealand as provided for by a delegation from the Authority under section 19(2)(d).
4
4.1
Southwell Products Ltd seeks approval, under section 28, to import or manufacture Chlorine Dioxide in Aqueous Solution for release in New Zealand.
4.2
An application can be assessed by rapid assessment procedures, under section
28A(2)(b), if it can be shown that Chlorine Dioxide in Aqueous Solution has one or more hazardous properties and each hazardous property has the least degree of hazard for that property.
4.3
The approach adopted when considering this application was:
 to review the information provided;
 to identify the composition and hazardous properties of the proposed substance, Chlorine Dioxide in Aqueous Solution;
Environmental Risk Management Authority Decision: Application HSR08017 Page 2 of 23

 to determine whether Chlorine Dioxide in Aqueous Solution has one or more hazardous properties and each hazardous property has the least degree of hazard for that property.
4.4
And then:
 to consider whether there are any other effects that mean Chlorine
Dioxide in Aqueous Solution should not be approved under section 28A; and
 to consider whether the controls that apply under the Act will prevent or manage the adverse effects of Chlorine Dioxide in Aqueous Solution.
4.5
The project team has reviewed the information supplied by Southwell Products
Ltd, and considers that the information constitutes an adequate and appropriate basis for assessing the application (clause 8). They also consider that there are no significant uncertainties (ie sufficient to influence decision making) in the scientific and technical information relating to the risks of Chlorine Dioxide in
Aqueous Solution (clauses 29 and 30).
4.6
Chlorine Dioxide in Aqueous Solution is a soluble concentrate containing chlorine dioxide as the active ingredient.
4.7
Chlorine Dioxide in Aqueous Solution is intended for use as a broad spectrum fungicide on apples, pears, grapes, stone fruit, kiwi fruit, tangelos, berryfruit, asparagus, greenhouse tomatoes, fine turf and cotular.
4.8
The project team has determined the hazard profile of Chlorine Dioxide in
Aqueous Solution based on the information provided by the applicant and other available information. The hazard classifications for Chlorine Dioxide in
Aqueous Solution are set out in Table 4.1.
Table 4.1: Hazard classification
Hazardous Property
Aquatic Ecotoxicity
Chlorine Dioxide in
Aqueous Solution
9.1D
4.9
Based on the information presented in Table 4.1, the project team considers that the criteria for rapid assessment under section 28A(2)(b) have been met in that the substance has been formulated with the hazardous property having the least degree of hazard for that property.
Environmental Risk Management Authority Decision: Application HSR08017 Page 3 of 23

4.10
The project team considers that there are no other matters which would prevent this application for Chlorine Dioxide in Aqueous Solution from being rapidly assessed.
5
5.1
Based on the hazard classifications determined for the proposed substance, a set of associated default controls has been identified by the project team as being applicable to Chlorine Dioxide in Aqueous Solution. These default controls, expressed as control codes
1
, are listed in Table 5.1
.
5.2
Additional controls under section 77A are available to manage the risks associated with Chlorine Dioxide in Aqueous Solution, which are not addressed by the default controls. These are considered in paragraph 5.11.2 below.
Table 5.1: List of default controls for Chlorine Dioxide in Aqueous Solution
Ecotoxicity Controls
E1 Limiting exposure to ecotoxic substances through the setting of EELs
E2
E6
Restrictions on use of substances in application areas
Requirements for equipment used to handle substances
Identification Controls
I1 Identification requirements, duties of persons in charge, accessibility, comprehensibility, clarity and durability
I9
I11
I19
I21
I29
Secondary identifiers for all hazardous substances
Secondary identifiers for ecotoxic substances
Additional information requirements, including situations where substances are in multiple packaging
General documentation requirements
Signage requirements
Packaging Controls
P1 General packaging requirements
P3 Criteria that allow substances to be packaged to a standard not meeting
Packing Group I, II or III criteria
PS4 Packaging requirements as specified in Schedule 4
Disposal Controls
D5
D6
D7
D8
Disposal requirements for ecotoxic
Disposal requirements for packages
Information requirements for manufacturers, importers and suppliers, and persons in charge
Documentation requirements for manufacturers, importers and suppliers, and persons in charge
Emergency Management Controls
EM1 Level 1 information requirements for suppliers and persons in charge
EM7 Information requirements for ecotoxic substances
EM8 Level 2 information requirements for suppliers and persons in charge
EM11 Level 3 emergency management requirements: duties of person in charge,
1 Control codes are those assigned by ERMA NZ to enable easy cross reference with the regulations. A detailed list of these codes is contained in the ERMA New Zealand User Guide to the Controls Regulations.
Environmental Risk Management Authority Decision: Application HSR08017 Page 4 of 23

emergency response plans
EM12 Level 3 emergency management requirements: secondary containment
EM13 Level 3 emergency management requirements: signage
Tank Wagon and Transportable Containers Controls
The Hazardous Substance (Tank Wagons and Transportable Containers) Regulations
2004 prescribe a number of controls relating to tank wagons and transportable containers.
5.3
5.4
The project team has evaluated the potential of Chlorine Dioxide in Aqueous
Solution to cause adverse effects to the environment (non-target organisms) during all stages of the substance’s lifecycle. Quantitative and qualitative risk assessments were carried out to assess these risks (refer to Appendix 2 for qualitative descriptors of risk).
Assessment of risks to the environment
Chlorine Dioxide in Aqueous Solution is classified as 9.1D (aquatic ecotoxicant). A quantitative risk assessment was carried out by the project team to consider the risks to the environment during use of the proposed substance.
Acute risk was identified for fish, but the project team considers that this risk can be mitigated through restricted use (see Appendix 3 for detail) by means of adding the approved handlers control E7.
5.5
A qualitative risk assessment was carried out by the project team to consider the risks to the environment over the remainder of the product life-cycle. The risks are considered to be negligible based on the following:
5.5.1
The project team considers that it is highly improbable that the environment will be exposed to these substances in such a manner as to cause any adverse effects, given adherence to HSNO controls (e.g. packaging, identification, emergency management and disposal), transport regulations and the Resource Management Act (RMA).
5.6
5.5.2
If exposure were to occur, the project team considers that the magnitude of any adverse effect will be minor as the effect would be localised with no discernible ecosystem impact.
Assessment of risks to human health
Chlorine Dioxide in Aqueous Solution has not been classified with any toxic properties; however, the chlorine dioxide in its gaseous, undiluted form is extremely toxic to humans. Human exposure would be via inhalation upon application of the proposed substance during use, but the risk of adverse effect is assessed by the project team as being negligible due to the very low concentration at which chlorine dioxide is present in the formulation.
5.7
The project team notes that the hazard classifications triggered by Chlorine
Dioxide in Aqueous Solution give rise to the potential for cultural risk including the deterioration of the mauri of taonga flora and fauna species, the environment
Environmental Risk Management Authority Decision: Application HSR08017 Page 5 of 23

5.8
and the general health and well-being of individuals and the community. In addition, the introduction and use of this substance has the potential to inhibit the ability of iwi/Māori to fulfil their role as kaitiaki.
On considering the information available, the project team considers a minimal impact from Chlorine Dioxide in Aqueous Solution on the relationship of Māori and their culture and traditions with their ancestral lands, water, sites, wāhi tapu, valued flora and fauna and other taonga to be highly improbable . In addition there is no evidence to suggest that the controlled use of Chlorine Dioxide in
Aqueous Solution will breach the principles of the Treaty of Waitangi.
5.9
The overall level of risk is therefore considered to be negligible given that the substance is handled, stored, transported, used, and disposed of, in accordance with the explicitly stated default and additional controls proposed in this report, and any other controls required by other legislation.
5.10
However, the project team notes that should inappropriate use, or accident, result in the contamination of waterways or the environment generally, that users notify the appropriate authorities including the relevant iwi authorities in that region. This action should include advising them of the contamination and the measures taken to contain and remediate.
5.11
The project team has reviewed the effectiveness of the default controls for
Chlorine Dioxide in Aqueous Solution in managing the identified risks and costs associated with the substance. Consequently a number of variations of the default controls and additional controls are considered appropriate. The variations, additions and the setting of exposure limits and applications rates are discussed below.
Controls relating to the setting of exposure limits and application rates
5.11.1
The controls relating to the setting of exposure limits are varied as follows:
Controls Comment
E1 No EEL values are set for any component of Chlorine Dioxide in
Aqueous Solution at this time and the default EEL values are deleted.
E2 As no EEL value has been set, no application rate is required to be set at this time. However, a maximum application rate and application frequency has been set as an additional control under
77A (see paragraph 5.11.2 below) for Chlorine Dioxide in
Aqueous Solution on the basis of quantitative risk assessment modelling conducted by the project team.
Additional controls
5.11.2
The following controls are added under section 77A as being more effective in terms of their effect on the management, use and risks of
Chlorine Dioxide in Aqueous Solution:
Environmental Risk Management Authority Decision: Application HSR08017 Page 6 of 23

Controls Comment
Though the proposed substance has not had any toxic hazard classifications conferred on it by the project team, as discussed in the risk assessment section, chlorine dioxide is extremely toxic to humans in its concentrated form. In order to mitigate any risks to users associated with exposure to the proposed substance, the project team has set the Department of Labour WES for chlorine dioxide as follows: chlorine dioxide: TWA
1
: 0.1 ppm (0.28 mg/m
3
)
The project team considers that the application rate proposed by the applicant and used in the quantitative risk assessment modelling should be set as a maximum application rate (see Appendix 3 for detail regarding the modelling), as being more effective in managing the risk of unintended exposure to the aquatic environment than the default controls: max. application rate: 0.02 kg ai/ha
E7/AH1 The proposed use in New Zealand is to be widely dispersive as a pesticide. Based on the results of a quantitative assessment the project team considers that applying the Approved Handler control will be more effective in managing the risk of unintended exposure to the aquatic environment than the default controls.
EM12 The following subclauses are added after subclause (3) of regulation 36 2 (control EM12):
(4) For the purposes of this regulation, and regulations 37 to
40, where this substance is contained in pipework that is installed and operated so as to manage any loss of containment in the pipework it—
(a) is not to be taken into account in determining whether a place is required to have a secondary containment system; and
(b) is not required to be located in a secondary containment system.
(5) In this clause, pipework—
(a) means piping that—
(i) is connected to a stationary container; and
(ii) is used to transfer a hazardous substance into or out of the stationary container; and
(b) includes a process pipeline or a transfer line.
EM12 The following subclauses are added after subclause (3) of regulation 37 1 (control EM12):
(2) If pooling substances which do not have class 1 to 5 hazard classifications are held in a place above ground in containers each of which has a capacity of 60 litres or less—
(a if the place’s total pooling potential is less than
20,000 litres, the secondary containment system must have a capacity of at least 25% of that total pooling potential:
(b) if the place’s total pooling potential is 20,000 litres or more, the secondary containment system must have a
1 TWA: Time Weighted Average
2 Hazardous Substances (Emergency Management) Regulations 2001
Environmental Risk Management Authority Decision: Application HSR08017 Page 7 of 23

Controls Comment capacity of the greater of—
(i) 5% of the total pooling potential; or
(ii) 5,000 litres.
(3) Pooling substances to which subclause (2) applies must be segregated where appropriate to ensure that leakage of one substance may not adversely affect the container of another substance.
EM12 The following subclauses are added after subclause (3) of regulation 38 1 (control EM12):
(2) If pooling substances which do not have class 1 to 5 hazard classifications are held in a place above ground in containers 1 or more of which have a capacity of more than
60 litres but none of which have a capacity of more than
450 litres—
(a) if the place’s total pooling potential is less than 20,000 litres, the secondary containment system must have a capacity of either 25% of that total pooling potential or
110% of the capacity of the largest container, whichever is the greater:
(b) if the place’s total pooling potential is 20,000 litres or more, the secondary containment system must have a capacity of the greater of—
(i) 5% of the total pooling potential; or
(ii) 5,000 litres
(3) Pooling substances to which subclause (2) applies must be segregated where appropriate to ensure that the leakage of one substance may not adversely affect the container of another substance.
Sch 8 Addition of controls relating to stationary container systems as set out in Schedule 8 1
Use
Control
Addition of a use restriction control as follows:
Chlorine Dioxide in Aqueous Solution shall not be applied onto or into water 2 .
5.12
The additions and modifications to the default controls for Chlorine Dioxide in
Aqueous Solution, as above, have been incorporated into the list of controls for
Chlorine Dioxide in Aqueous Solution detailed in Appendix 1.
6
6.1
The project team considers that use of controls on Chlorine Dioxide in Aqueous
Solution is an effective means of managing risks associated with this substance.
At this time, no consideration has been given to whether or not environmental charges should be applied to this substance as an alternative or additional means of achieving effective risk management. Accordingly, no report has been made to the Minister for the Environment.
1 Hazardous Substances (Dangerous Goods and Scheduled Toxic Substances) Transfer Notice 2004 (Supplement to the New Zealand
Gazette, 26 March 2004, No. 35, page 767), as amended
2 where ‘water’ means water in all its physical forms, whether flowing or not, and whether over or under ground, but does not include water in any form while in a pipe, tank or cistern.
Environmental Risk Management Authority Decision: Application HSR08017 Page 8 of 23

7
7.1
Pursuant to section 28A, I have considered this application to import or manufacture a hazardous substance for release made under section 28.
7.2
Having considered the composition, hazardous properties, and proposed use of
Chlorine Dioxide in Aqueous Solution, I am satisfied that the proposed substance meets the criteria for rapid assessment under section 28A(2)(b) in that it has one or more hazardous properties and each hazardous property has the least degree of hazard for that property.
7.3
I am satisfied with the hazard classifications identified by the project team in paragraph 4.8 and accordingly confer them on the proposed substance.
7.4
As the risks posed by Chlorine Dioxide in Aqueous Solution are negligible, I consider that applying the HSNO default controls to Chlorine Dioxide in
Aqueous Solution, with the additions and amendments proposed under paragraphs 5.11 to 5.11.2 (inclusive), will ensure adequate management of any adverse effects of Chlorine Dioxide in Aqueous Solution.
7.5
In this consideration, I have also applied the following criteria in the
Methodology:
 clause 9 – equivalent of sections 5, 6 and 8;
 clause 12 – risk assessment;
 clause 21 – the decision accords with the requirements of the Act and regulations;
 clause 24 – the use of recognised risk identification, assessment, evaluation and management techniques;
 clause 25 – the evaluation of risks; and
 clause 35 – the costs and benefits of varying the default controls.
7.6
The application for importation and manufacture of the hazardous substance,
Chlorine Dioxide in Aqueous Solution for release is thus approved with controls as detailed in Appendix 1.
Rob Forlong
Chief Executive, ERMA New Zealand
Chlorine Dioxide in Aqueous Solution
ERMA New Zealand Approval Code:
Date: 2 July 2008
HSR007938
Environmental Risk Management Authority Decision: Application HSR08017 Page 9 of 23

The controls imposed on Chlorine Dioxide in Aqueous Solution are as follows. The regulations cited should be referred to for definitions and exemptions. The ERMA New
Zealand publication User Guide to Control Regulations provides useful guidance on the controls.
Table A1.1: Controls for Chlorine Dioxide in Aqueous Solution – codes, regulations and variations
Control
Code 1 Regulation 2 Topic Variations
Hazardous Substances (Classes 6, 8 and 9 Controls) Regulations 2001 - Ecotoxic Property
Controls
E1
E2
32 – 45
46 – 48
Limiting exposure to ecotoxic substances through the setting of EELs
Restrictions on use of substances in application areas
No EEL values are set for
Chlorine Dioxide in Aqueous
Solution at this time and the default EEL values are deleted.
A maximum application rate has been set for Chlorine Dioxide in
Aqueous Solution, as an additional control under 77A
(see below).
E6
E7
7
9
Requirements for equipment used to handle substances
Approved handler/security requirements for certain ecotoxic substances
Hazardous Substances (Identification) Regulations 2001
I1 6, 7, 32-35, General identification requirements
36 (1)-(7)
Regulation 6 – Identification duties of suppliers
Regulation 7 – Identification duties of persons in charge
Regulations 32 and 33 – Accessibility of information
Regulations 34, 35, 36(1)-(7) –
Comprehensibility, Clarity and
Durability of information
I9
I11
18
20
Secondary identifiers for all hazardous substances
Secondary identifiers for ecotoxic substances
This control has been added under section 77A (see below).
1
Note: The numbering system used in this column relates to the coding system used in the ERMA New Zealand Controls Matrix. This links the hazard classification categories to the regulatory controls triggered by each category. It is available from the ERMA New Zealand website www.ermanz.govt.nz/resources and is also contained in the ERMA New Zealand User Guide to the HSNO Control Regulations.
2 These Regulations form the controls applicable to this substance. Refer to the cited Regulations for the formal specification, and for definitions and exemptions. The accompanying explanation is intended for guidance only.
Environmental Risk Management Authority Decision: Application HSR08017 Page 10 of 23

Control
Code 1
I19
I21
I29
Regulation 2 Topic
29-31 Alternative information in certain cases
Regulation 29 – Substances in fixed bulk containers or bulk transport containers
Regulation 30 – Substances in multiple packaging
Regulation 31 – Alternative information when substances are imported
37-39, 47-
50
Documentation required in places of work
51, 52
Regulation 37 – Documentation duties of suppliers
Regulation 38 – Documentation duties of persons in charge of places of work
Regulation 39 – General content requirements for documentation
Regulation 47 – Information not included in approval
Regulation 48 – Location and presentation requirements for documentation
Regulation 49 – Documentation requirements for vehicles
Regulation 50 – Documentation to be supplied on request
Specific documentation requirements for ecotoxic substances
Hazardous Substances (Packaging) Regulations 2001
P1 5, 6, 7 (1), 8 General packaging requirements
Regulation 5 – Ability to retain contents
Regulation 6 – Packaging markings
Regulation 7(1) – Requirements when packing hazardous substance
Regulation 8 – Compatibility
Variations
Environmental Risk Management Authority Decision: Application HSR08017 Page 11 of 23

Control
Code
P3
PS4
1 Regulation 2 Topic
Regulation 9A and 9B – Large
Packaging
9 Packaging requirements for substances packed in limited quantities
Schedule 4 This schedule describes the minimum packaging requirements that must be complied with for this substance.
Variations
Hazardous Substances (Disposal) Regulations 2001
D5 9 Disposal requirements for ecotoxic
D6
D7
10
11, 12
Disposal requirements for packages
Disposal information requirements
D8 13, 14 Disposal documentation requirements
Hazardous Substances (Emergency Management) Regulations 2001
EM1 6, 7, 9-11
EM7 8(f)
Level 1 emergency management information: General requirements
Information requirements for ecotoxic substances
EM8
EM11
EM12
12-16, 18-
20
25-34
35-41
Level 2 emergency management documentation requirements
Level 3 emergency management requirements: duties of person in charge, emergency response plans
Level 3 emergency management requirements: duties of person in charge, emergency response plans
The following subclauses are added after subclause (3) of regulation 36:
(4) For the purposes of this regulation, and regulations 37 to 40, where this substance is contained in pipework that is installed and operated so as to manage any loss of containment in the pipework it—
(a) is not to be taken into account in determining whether a place is required to have a secondary containment system; and
(b) is not required to be located in a secondary containment system.
(5) In this clause, pipework—
(a) means piping that—
(i) is connected to a stationary container; and
(ii) is used to transfer a hazardous substance into or out of the stationary container; and
(b) includes a process pipeline or a transfer line.
Environmental Risk Management Authority Decision: Application HSR08017 Page 12 of 23

Control
Code 1 Regulation 2 Topic Variations
The following subclauses are added at the end of regulation
37:
(2) If pooling substances which do not have class 1 to 5 hazard classifications are held in a place above ground in containers each of which has a capacity of 60 litres or less—
(a if the place’s total pooling potential is less than
20,000 litres, the secondary containment system must have a capacity of at least
25% of that total pooling potential:
(b) if the place’s total pooling potential is 20,000 litres or more, the secondary containment system must have a capacity of the greater of—
(i) 5% of the total pooling potential; or
(ii) 5,000 litres.
(3) Pooling substances to which subclause (2) applies must be segregated where appropriate to ensure that leakage of one substance may not adversely affect the container of another substance.
The following subclauses are added at the end of regulation
38:
(2) If pooling substances which do not have class 1 to 5 hazard classifications are held in a place above ground in containers 1 or more of which have a capacity of more than 60 litres but none of which have a capacity of more than 450 litres—
(a) if the place’s total pooling potential is less than
20,000 litres, the secondary containment system must have a capacity of either
25% of that total pooling potential or 110% of the capacity of the largest container, whichever is the greater:
(b) if the place’s total pooling
Environmental Risk Management Authority Decision: Application HSR08017 Page 13 of 23

Control
Code 1 Regulation 2 Topic Variations potential is 20,000 litres or more, the secondary containment system must have a capacity of the greater of—
(i) 5% of the total pooling potential; or
(ii) 5,000 litres
(3) Pooling substances to which subclause (2) applies must be segregated where appropriate to ensure that the leakage of one substance may not adversely affect the container of another substance.
EM13 42 Level 3 emergency management requirements: signage
Hazardous Substances (Personnel Qualifications) Regulations 2001
AH1 4 – 6 Approved Handler requirements See control E7.
(including test certificate and qualification requirements)
Hazardous Substances (Tank Wagons and Transportable Containers) Regulations 2004
Regulations 4 to 43 The Hazardous Substances (Tank where applicable Wagons and Transportable Containers)
Regulations 2004 prescribe a number of controls relating to tank wagons and transportable containers and must be complied with as relevant.
Additional controls set under s77A
WES set for chlorine dioxide: TWA: 0.1 ppm (0.28 mg/m 3 ) maximum application rate: 0.02 kg ai/ha
Addition of controls E7 and AH1 (see paragraph 5.11.2).
Addition of subclauses after subclause (3) of regulation 36 and at the end of regulations 37 and 38 of the Hazardous Substances (Emergency Management Controls) Regulations 2001 (control EM12).
The controls relating to stationary container systems, as set out in Schedule 8 of the Hazardous
Substances (Dangerous Goods and Scheduled Toxic Substances) Transfer Notice 2004 (Supplement to the New Zealand Gazette, 26 March 2004, No. 35, page 767), as amended, shall apply to this substance, notwithstanding clause 1(1) of that schedule.
Chlorine Dioxide in Aqueous Solution shall not be applied onto or into water.
Environmental Risk Management Authority Decision: Application HSR08017 Page 14 of 23

A2.1 Assessing risks, costs and benefits qualitatively
This section describes how the Agency staff and the Authority address the qualitative assessment of risks, costs and benefits.
Risks and benefits are assessed by estimating the magnitude and nature of the possible effects and the likelihood of their occurrence. For each effect, the combination of these two components determines the level of the risk associated with that effect, which is a two dimensional concept.
Because of a lack of data, risks are often presented as singular results. In reality, they are better represented by ‘families’ of data which link probability with different levels of outcome (magnitude).
A2.2 Describing the magnitude of effect
The magnitude of effect is described in terms of the element that might be affected. The qualitative descriptors for magnitude of effect are surrogate measures that should be used to gauge the end effect or the ‘what if’ element.
Tables A2.1 and A2.3 contain generic descriptors for magnitude of adverse and beneficial effect. These descriptors are examples only, and their generic nature means that it may be difficult to use them in some particular circumstances. They are included here to illustrate how qualitative tables may be used to represent levels of adverse and beneficial effect.
The sample qualitative descriptors for effects on the market economy listed in the ERMA
New Zealand technical guide to decision making 1 include representative numbers. These
‘economic’ descriptors were developed prior to the publication of the technical guide on identification and assessment of effects on the market economy, 2 which refines the approach that ERMA New Zealand applies to identifying and assessing economic effects. These numbers do not align well with the qualitative descriptors in the other categories (effects on the environment, effects on human health, and effects on society and communities), as they relate more to an event than an effect. In particular the numbers are unclear about how they take account of time (are they annual, or over the life of the activity) and they do not have a local, regional or national context.
ERMA New Zealand has adopted a revised set of qualitative descriptors for the magnitude of effect on the market economy, as shown below.
Table A2.1: Magnitude of adverse effect (risks and costs).
Descriptor
Minimal
Examples of descriptions: ADVERSE
Mild reversible short term adverse health effects to individuals in highly localised area
Highly localised and contained environmental impact, affecting a few (less than ten) individuals members of communities of flora or fauna, no discernible ecosystem impact
Local/regional short-term adverse economic effects on small organisations
1 ERMA New Zealand. 2004. Decision Making: A Technical Guide to Identifying, Assessing and Evaluating Risks, Costs and Benefits ,
ER-TG-05-01. Wellington: Environmental Risk Management Authority.
2 ERMA New Zealand. 2005. Assessment of Economic Risks, Costs and Benefits: Consideration of Impacts on the Market Economy , ER-
TG-06-01. Wellington: Environmental Risk Management Authority.
Environmental Risk Management Authority Decision: Application HSR08017 Page 15 of 23

Descriptor
Minor
Moderate
Major
Massive
Examples of descriptions: ADVERSE
(businesses, individuals), temporary job losses
No social disruption
Mild reversible short term adverse health effects to identified and isolated groups
Localised and contained reversible environmental impact, some local plant or animal communities temporarily damaged, no discernible ecosystem impact or species damage
Regional adverse economic effects on small organisations (businesses, individuals) lasting less than six months, temporary job losses
Potential social disruption (community placed on alert)
Minor irreversible health effects to individuals and/or reversible medium term adverse health effects to larger (but surrounding) community (requiring hospitalisation)
Measurable long term damage to local plant and animal communities, but no obvious spread beyond defined boundaries, medium term individual ecosystem damage, no species damage
Medium term (one to five years) regional adverse economic effects with some national implications, medium term job losses
Some social disruption (e.g. people delayed)
Significant irreversible adverse health effects affecting individuals and requiring hospitalisation and/or reversible adverse health effects reaching beyond the immediate community
Long term/irreversible damage to localised ecosystem but no species loss
Measurable adverse effect on GDP, some long term (more than five years) job losses
Social disruption to surrounding community, including some evacuations
Significant irreversible adverse health effects reaching beyond the immediate community and/or deaths
Extensive irreversible ecosystem damage, including species loss
Significant on-going adverse effect on GDP, long term job losses on a national basis
Major social disruption with entire surrounding area evacuated and impacts on wider community
Table A2.2: Magnitude of beneficial effect (benefits).
Descriptor
Minimal
Minor
Moderate
Examples of descriptions: BENEFICIAL
Mild short term positive health effects to individuals in highly localised area
Highly localised and contained environmental impact, affecting a few (less than ten) individuals members of communities of flora or fauna, no discernible ecosystem impact
Local/regional short-term beneficial economic effects on small organisations
(businesses, individuals), temporary job creation
No social effect
Mild short term beneficial health effects to identified and isolated groups
Localised and contained beneficial environmental impact, no discernible ecosystem impact
Regional beneficial economic effects on small organisations (businesses, individuals) lasting less than six months, temporary job creation
Minor localised community benefit
Minor health benefits to individuals and/or medium term health impacts on larger (but surrounding) community and health status groups
Measurable benefit to localised plant and animal communities expected to pertain to
Environmental Risk Management Authority Decision: Application HSR08017 Page 16 of 23

Descriptor
Major
Massive
Examples of descriptions: BENEFICIAL medium term.
Medium term (one to five years) regional beneficial economic effects with some national implications, medium term job creation
Local community and some individuals beyond immediate community receive social benefit.
Significant beneficial health effects to localised community and specific groups in wider community
Long term benefit to localised ecosystem(s)
Measurable beneficial effect on GDP, some long term (more than five years) job creation
Substantial social benefit to surrounding community, and individuals in wider community.
Significant long term beneficial health effects to the wider community
Long term, wide spread benefits to species and/or ecosystems
Significant on-going effect beneficial on GDP, long term job creation on a national basis
Major social benefit affecting wider community
A2.3 Determining the likelihood of the end effect
Likelihood in this context applies to the composite likelihood of the end effect, and not either to the initiating event, or any one of the intermediary events. It includes:
 the concept of an initiating event (triggering the hazard), and
 the exposure pathway that links the source (hazard) and the area of impact
(public health, environment, economy, or community).
Thus, the likelihood is the likelihood of the specified adverse effect 1 resulting from that initiating event. It will be a combination of the likelihood of the initiating event and several intermediary likelihoods 2 . The best way to determine the likelihood is to specify and analyse the complete pathway from source to impact.
Likelihood may be expressed as a frequency or a probability. While frequency is often expressed as a number of events within a given time period, it may also be expressed as the number of events per head of (exposed) population. As a probability, the likelihood is dimensionless and refers to the number of events of interest divided by the total number of events (range 0–1). (See Table A2.3.)
Table A2.3: Likelihood.
Descriptor Description
1
2
3
4
Highly improbable
Improbable
(remote)
Very unlikely
Unlikely
Almost certainly not occurring but cannot be totally ruled out
Only occurring in very exceptional circumstances.
Considered only to occur in very unusual circumstances
Could occur, but is not expected to occur under normal operating
1 The specified effect refers to scenarios established in order to establish the representative risk, and may be as specific as x people suffering adverse health effects, or y% of a bird population being adversely affected. The risks included in the analysis may be those related to a single scenario, or may be defined as a combination of several scenarios.
2 Qualitative event tree analysis may be a useful way of ensuring that all aspects are included.
Environmental Risk Management Authority Decision: Application HSR08017 Page 17 of 23

5
6
7
Descriptor
(occasional)
Likely
Very likely
Extremely likely
Description conditions.
A good chance that it may occur under normal operating conditions.
Expected to occur if all conditions met
Almost certain
A2.4 Using magnitude and likelihood to construct the level of risk and benefit
Using the magnitude and likelihood tables a matrix representing a level of effect can be constructed (Table A2.4).
Table A2.4: Level of effect.
Magnitude of effect
Likelihood Minimal Minor Moderate Major Massive
Highly improbable
Improbable
Very unlikely
Unlikely
Likely
Very likely
A
A
B
C
D
E
A
B
C
D
E
E
B
C
D
E
E
F
C
D
E
E
F
F
D
Extremely likely
E F F F
The Agency considers that, for this substance, the level of risk/benefit can be assigned as follows in Table A2.5.
F
E
E
F
F
F
Table A2.5: Assignment of level of risk/benefit .
A & B
C
D
E
F
Negligible
Low
Medium
High
Extreme
Environmental Risk Management Authority Decision: Application HSR08017 Page 18 of 23

The applicant provides the following information that is relevant to assess the environmental risks.
Chlorine dioxide has a high water solubility, especially in cold water, and it does not hydrolyze when it enters water. Chlorine dioxide remains a dissolved gas in solution.
It is a very unstable substance and it decomposes when it comes in contact with sunlight. The best way to store the product is as a liquid at 4 o C. Chlorine dioxide gas is used to sterilise medical and laboratory equipment, surfaces, rooms and tools. As a disinfectant and pesticide it is mainly used in liquid form. According to the MSDS the product is not anticipated to cause adverse effects to animal or plant life if released to the environment in small quantities.
It is not expected to bio-accumulate.
US EPA assessed chlorine dioxide used as a disinfectant, a sanitizer and a sterilant.
The application rate varies from 1 till 1406 ppm depending on the use. Chlorine dioxide has a short half-life and in the presence of sunlight will break down into chloride and chlorate ions
(between pH 4 and 7). At pH lower than 4, its breakdown products are chlorite and chlorate.
Chlorite is the dominant breakdown product. Chlorate and chlorite ions tend only undergo biodegradation under anaerobic conditions. The end products are the chloride and oxygen. No adsorption/desorption constants have been measured for either chlorite or chlorate. These ions are likely to be mobile and may travel from surface to groundwater easily. The estimated
K ow
of chlorine dioxide is – 3.22. It is not expected that chlorine dioxide would bioaccumulate in aquatic organisms.
US EPA assessed the risk for the use in cooling towers at the application rate of 25 ppm. The conclusion is that there is a risk to freshwater and marine/estuarine fish, invertebrates and aquatic plants. To mitigate the risk the maximum application rate is set on 5 ppm. All other exposure and risk estimates are below US EPA’s level of concern.
Due to the proposed uses in New Zealand the environmental exposure will be greater than the exposure assessed by US EPA. Therefore the Agency runs the Generic Estimated
Environmental Concentration Model v2 (GENEEC2) surface water exposure model (USEPA
2001) to assess the risk for the aquatic organisms. The calculations provide an Estimated
Environmental Concentration (EEC) which, when divided by the LC
50
or EC
50
, gives a risk quotient (RQ).
Acute RQ = EEC short term
LC
50
or EC
50
Chronic RQ = EEC long term
NOEC
If the RQ exceeds a predefined level of concern, this suggests that it may be appropriate to refine the assessment or to apply the approved handler control
(AH) control and/or other controls to ensure that appropriate matters are taken into account to minimize off-site movement of the substance. Conversely, if a worst-case scenario is used, and the level of concern is not exceeded, then in terms of the environment, there is a presumption of low risk which is able to be adequately managed by such things as label statements (warnings, disposal). The AH control can then be removed on a selective basis.
Environmental Risk Management Authority Decision: Application HSR08017 Page 19 of 23

Levels of concern (LOC) developed by the USEPA (Urban and Cook 1986) and adopted by
ERMA New Zealand, to determine whether a substance poses an environmental risk are provided in Table 2.
Table 1: Levels of concern as adopted by ERMA New Zealand
Endpoint LOC Presumption
Aquatic (fish, invertebrates)
Acute RQ≥
0.5 High acute risk
Acute RQ 0.1-0.5 Risk can be mitigated through restricted use
Acute RQ< 0.1
Chronic RQ≥
1
Low risk
High chronic risk
Plants (aquatic and terrestrial)
Acute RQ≥ 1 High acute risk
Mammals and birds
Acute dietary 0.5
RQ≥
Acute oral dose 0.5
[granular products] RQ≥
Chronic RQ≥
1
High acute risk
High acute risk
High chronic risk
The parameters used in the GENEEC2 modeling are listed in Table 3 and represent the recommended use on grapes.
Table 2: Input parameters for GENEEC2 analysis
Chlorine dioxide Reference
Application rate 0.02 kg ai/ha
Application frequency
Application interval
3-5
10
Data provided by applicant for SOS application
Agency’s assumptions based on the intended use, the applicant stated that it can be used as often as required.
K d
/K oc
0.000211 As both K d and K oc are not known, the Agency used a default of 0.35 x
K ow
.
Estimated Log K ow
= -3.22,
K ow
= 0.000603 [source EPA RED chlorine dioxide, 2006]
Aerobic soil DT
50
Pesticide wetted in?
0
No
Methods of application Airblast spray
Not known
Environmental Risk Management Authority Decision: Application HSR08017 Page 20 of 23

‘No spray’ zone
Water solubility
Aerobic aquatic DT
50
0
3010 mg/L
0
EPA RED chlorine dioxide, 2006
Not known
Aqueous photolysis
DT
50
0 Not known
Hydrolysis 0 Not known
The Agency run the model twice for 5 and 3 applications. Due to a lack on data the Agency used the default for some values.
Output from the GENEEC2 model.
5 applications
RUN No. 2 FOR chlorine dioxide ON grapes * INPUT VALUES *
--------------------------------------------------------------------------------------------
RATE (lb/ac) No.APPS & SOIL SOLUBIL APPL TYPE NO-SPRAY INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) ZONE(FT) (IN)
--------------------------------------------------------------------------------------------
.018( .089) 5 10 .0 3010.0 ORCHAR( 9.7) .0 .0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
-------------------------------------------------------------------------------------------------
METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED
(FIELD) RAIN/RUNOFF (POND) (POND-EFF) (POND) (POND)
------------------------------------------------------------------------------------------------
.00 2 N/A .00- .00 .00 .00
GENERIC EECs (IN MICROGRAMS/LITER (PPB)) Version 2.0 Aug 1, 2001
---------------------------------------------------------------------------------------------
PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY
GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC
-------------------------------------------------------------------------------------------
5.43 5.43 5.43 5.43 5.43
3 applications
RUN No. 1 FOR chlorine dioxide ON grapes * INPUT VALUES *
-------------------------------------------------------------------------------------------
RATE (lb/ac) No.APPS & SOIL SOLUBIL APPL TYPE NO-SPRAY INCORP
ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) ZONE(FT) (IN)
-------------------------------------------------------------------------------------------
.018( .053) 3 10 .0 3010.0 ORCHAR( 9.7) .0 .0
FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)
----------------------------------------------------------------------------------------------
METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED
(FIELD) RAIN/RUNOFF (POND) (POND-EFF) (POND) (POND)
------------------------------------------------------------------------------------------------
.00 2 N/A .00- .00 .00 .00
Environmental Risk Management Authority Decision: Application HSR08017 Page 21 of 23

GENERIC EECs (IN MICROGRAMS/LITER (PPB)) Version 2.0 Aug 1, 2001
------------------------------------------------------------------------------------------------
PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY
GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC
---------------------------- --------------------------------------------------------------------
3.26 3.26 3.26 3.26 3.26
The Estimated Environmental Concentration (EEC) for chlorine dioxide as estimated by
GENEEC2 is:
5 applications: Peak and chronic EEC 0.00543 mg/L.
3 applications: Peak and chronic EEC 0.00326 mg/L.
Assessment of acute risk
Information used in the risk assessment:
Species: Fathead minnow
Type of exposure: Flow through
Duration: 96 hr
Endpoint: LC50
Value: 0.02 mg/l
Reference: Wilde EW et al; Water Res 17 (10): 1327-32 (1983)
The Estimated Environmental Concentration (EEC) for chlorine dioxide as estimated by
GENEEC2 are shown in Table 4, along with the aquatic data for chlorine dioxide for the most sensitive species tested (further details on these toxicity data are included in Table
A2.7).
Table 3: Acute risk quotients derived from the GENEEC2 model and toxicity data.
Peak EEC from
GENEEC2 (mg/L)
LC
50
or EC
50
(mg/L)
RQ (Acute)
EEC/ LC
50
or EC
50
Fish
Crustacea
0.00543 (5 appl.) 0.02
-
0.272
-
Algae - -
Fish
Crustacea
0.00326 (3 appl.) 0.02
-
0.163
-
Algae - -
When compared against the relevant acute risk quotients (Table 4), the acute RQs derived from the GENEEC2 modeling for chlorine dioxide indicate the following:
For fish: the acute risk can be mitigated through restricted use
For crustacean and algae: it is not possible to assess the acute risk
Based on the acute RQs for fish, the Agency considers it is appropriate to introduce the approved handler controls for Southwell AC when it is used in a wide dispersive manner, or
Environmental Risk Management Authority Decision: Application HSR08017 Page 22 of 23

by a commercial contractor. Further, the Agency considers that the application rate proposed by the applicant and used in the modeling should be set as a maximum application rate.
Chlorine dioxide degrades very quickly therefore the Agency considers there is no need to restrict the application frequency.
Environmental Risk Management Authority Decision: Application HSR08017 Page 23 of 23