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Proposed Risk Management Approach for

Benzenamine, N-phenyl-, Reaction Products with Styrene and 2,4,4-Trimethylpentene
(BNST)

Chemical Abstracts Service Registry Number (CAS RN)
68921-45-9

Environment Canada
Health Canada

August 2009


Table of Contents

  1. Issue
  2. Background
  3. Why we need action
  4. Current used and industrial sectors
  5. Presence in the canadian environment and exposure sources
  6. Overview of existing actions
  7. Considerations
  8. Proposed objectives
  9. Proposed risk management
  10. Consultation approach
  11. Next steps / Proposed timeline
  12. References
This proposed risk management approach document builds on the previously released risk management scope document for Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene, and outlines the proposed control actions for this substance. Stakeholders are invited to submit comments on the content of this proposed risk management approach or provide other information that would help to inform decision making. Following this consultation period, the Government of Canada will initiate the development of the specific risk management instrument(s) where necessary. Comments received on the proposed risk management approach will be taken into consideration in developing the instrument(s). Consultation will also take place as instrument(s) are developed.

1. Issue

1.1 Categorization and the Challenge to Industry and Other Iinterested Stakeholders

The Canadian Environmental Protection Act, 1999 (CEPA 1999) (Canada 1999) requires the Minister of the Environment and the Minister of Health (the Ministers) to categorize substances on the Domestic Substances List (DSL). Categorization involves identifying those substances on the DSL that a) are considered to be persistent (P) and/or bioaccumulative (B), based on the criteria set out in the Persistence and Bioaccumulation Regulations, and "inherently toxic" (iT) to humans or other organisms; or b) present, to individuals in Canada, the greatest potential for exposure (GPE). In addition, the Act requires the Ministers to conduct screening assessments of substances that meet the categorization criteria. The assessment further determines whether the substance meets the definition of "toxic" set out in section 64 of the Act.

In December 2006, the Challenge identified 193 chemical substances through categorization which became high priorities for assessment due to their hazardous properties and their potential to pose risks to human health and the environment. In February 2007, the Ministers began publishing, for industry and stakeholder comment, profiles of batches containing 15 to 30 high-priority substances. New batches are released for comment every three months.

In addition, the information-gathering authority in section 71 of CEPA 1999 is used under the Challenge to gather specific information where it is required. The information that is collected through the Challenge will be used to make informed decisions and appropriately manage any risks that may be associated with these substances.

The substance Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene, Chemical Abstracts Service Registry Number (CAS RN)1 68921-45-9, referred to throughout this document as "BNST," is included in Batch 4 of the Challenge under the Chemicals Management Plan.

1.2 Final Screening Assessment Report Conclusion for BNST

A notice summarizing the scientific considerations of the final screening assessment report was published by Environment Canada and Health Canada in the Canada Gazette, Part I, for BNST on August 1, 2009, under subsection 77(6) of CEPA 1999. The final screening assessment report (Canada 2009) concluded that BNST is entering or may be entering the environment in a quantity or a concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity.

The final screening assessment report concluded that BNST meets the criteria for persistence and bioaccumulation as defined in the Persistence and Bioaccumulation Regulations made under CEPA 1999. The presence of BNST in the environment results primarily from human activity.

For further information on the final screening assessment report conclusions for BNST, refer to the final screening assessment report, available at http://www.chemicalsubstanceschimiques.gc.ca/challenge-defi/batch-lot_4_e.html.

1.3 Proposed Measure

As a result of a screening assessment of a substance under section 74 of CEPA 1999, the substance may be found to meet one or more of the criteria under section 64 of CEPA 1999. The Ministers can propose to take no further action with respect to the substance, add the substance to the Priority Substances List (PSL) for further assessment, or recommend the addition of the substance to the List of Toxic Substances in Schedule 1 of the Act. Under certain circumstances, the Ministers must make a specific proposal either to recommend addition to the List of Toxic Substances or to recommend the implementation of virtual elimination (or both). In this case, the Ministers proposed to recommend the addition of BNST to the List of Toxic Substances in Schedule 1. As a result, the Ministers will develop a regulation or instrument respecting preventive or control actions to protect the health of Canadians and the environment from the potential effects of exposure to this substance.

The final screening assessment report concluded that BNST meets the virtual elimination criteria set out in subsection 77(4) of CEPA 1999 because

  • BNST meets the criterion set out in paragraph 64(a) of CEPA 1999; and
  • BNST meets the criteria for persistence and bioaccumulation as defined in the Persistence and Bioaccumulation Regulations; and
  • the presence of BNST in the environment results primarily from human activity; and
  • BNST is not a naturally occurring radionuclide or a naturally occurring inorganic substance.

As a result, the process specified in CEPA 1999 for substances that meet the criteria for virtual elimination will be followed.

2. Background

2.1 Substance Information

BNST is an organic substance that is part of the diphenylamine chemical class. This substance is UVCB (Unknown or Variable Composition, Complex Reaction Products, or Biological Materials); i.e., it is not a discrete chemical and thus may be characterized by a variety of structures. The structures and corresponding Simplified Molecular Line Input Entry System (SMILES) presented here were chosen to represent the substance.

Table 1a presents other names, trade names and chemical classes for BNST. BNST was evaluated based on two structures that are representative of the UVCB substance. As it is not a discrete chemical, BNST may be characterized by multiple structures in order to provide a range of properties of the mixture. The selected representative structures are shown in Tables 1b and 1c. Information concerning sources, uses and releases are described in terms of BNST, as the data submitted under the Challenge were in reference to CAS RN 68921-45-9.

Table 1a. Substance identity for BNST
Chemical Abstracts Service Registry Number (CAS RN)68921-45-9
DSL NameBenzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene
National Chemical Inventories (NCI) names2Benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene (TSCA, EINECS, ENCS, AICS, PICCS, ASIA-PAC, NZIoC)
Other namesDiphenylamine reaction product with styrene and diisobutylene
Reaction product of N-phenylbenzenamine, ethenylbenzene, and diisobutylene
Amines
Chemical group
(DSL stream)
UVCB Organic
Major chemical class or useDiphenyl amines

 

Table 1b. Substance identity for representative Structure 1
Representative chemical formulaC28H35N
Representative chemical structure used to run estimation models Structure 1: BNST
Simplified Molecular Input Line Entry System (SMILES) used to run estimation modelsCC(C1=CC=CC=C1NC2=CC=CC=C2C(C)(C)CC(C)(C)C)C3=CC=CC=C3
Molecular mass385.60 g/mol

 

Table 1c. Substance identity for representative Structure 2
Representative chemical formulaC20H27N
Representative chemical structure used to run estimation models Structure 2: BNST
Simplified Molecular Input Line Entry System (SMILES) used to run estimation modelsCC(C)(CC(C)(C)C)C1=CC=C(NC2=CC=CC=C2)C=C1
Molecular mass281.44 g/mol

3. Why we need action

3.1 Characterization of Risk

Evidence that a substance is highly persistent and bioaccumulative as defined in the Persistence and Bioaccumulation Regulations (Canada 2000), when taken together with the potential for environmental release or formation and the potential for toxicity to organisms, provides a significant indication that it may be entering the environment under conditions that may have harmful long-term ecological effects (Environment Canada 2006). Substances that are persistent remain in the environment for a long time after being released, increasing the potential magnitude and duration of exposure. Substances that have long half-lives in mobile media (air and water) and partition into these media in significant proportions have the potential to cause widespread contamination. Releases of small amounts of bioaccumulative substances may lead to high internal concentrations in exposed organisms. Highly bioaccumulative and persistent substances are of special concern, since they may biomagnify in food webs, resulting in very high internal exposures, especially for top predators.

The importation volumes of BNST into Canada indicate the potential for releases to the Canadian environment. Information gathered to date indicates that the major use of the substance is as an additive in engine oil and commercial/industrial lubricants. Results from a tool used to estimate environmental releases indicate that a small portion (~1.5%) of the BNST used as an additive in engine oil and commercial/industrial lubricants could be released to the environment as a result of blending, use and improper disposal of lubricating oils. Both empirical and modelled data indicate that once this substance is released into the environment, the substance will partition into and remain in sediment and soil for a long time because of its stability in the environment. Due to its lipophilic character and persistence, the empirical and modelled data suggest that BNST will likely bioaccumulate and may biomagnify in trophic food chains. Empirical and modelled data have demonstrated the potential for toxicity to aquatic organisms. This information suggests that BNST has the potential to be released into the environment and cause ecological harm in Canada (Canada 2009).

4. Current used and industrial sectors

The primary end-use application of BNST is as an antioxidant additive in vehicle engine oils. It also has a minor use as an antioxidant additive in commercial/industrial lubricants. Antioxidants are added to stabilize lubricating oils and prevent polymerization that leads to the formation of engine-fouling residues.

Information submitted as part of the Challenge indicates that fewer than five companies manufactured between 1 000 000 and 10 000 000 kg. Most of the BNST manufactured in Canada is subsequently exported.

Fewer than five companies imported between 100 001 and 1 000 000 kg of BNST into Canada in 2006.

Based on the information received, the petroleum and chemical manufacturing sectors are the primary industrial sectors involved with the substance (Environment Canada 2008).

5. Presence in the canadian environment and exposure sources

5.1 Releases to the Environment

Releases of BNST to soil, municipal sewer and surface water are expected due to industrial wastewater discharge, leaks and spills of lubricants during use and also due to the improper disposal of used engine oils and lubricants. There are no existing environmental measurements of BNST in any media.

An estimate of the quantities of BNST released to the various environmental media was completed by Environment Canada (Environment Canada 2009a). The estimate utilized a variety of assumptions based on a life-cycle analysis, a consultant study (Environment Canada 2009b), information received from stakeholders, and emission scenario documents published by the Organisation for Economic Co-operation and Development (OECD 2004).

BNST may be released from industrial point sources due to manufacturing of the pure substance and lubricant blending. It is estimated that a negligible portion of the amount manufactured is released to municipal wastewater due to manufacturing of BNST in Canada. A small quantity (0.2%) of the amount of BNST used to blend lubricants in Canada is estimated to also be discharged to sewers as a result of container cleaning.

Approximately 98.3% of the BNST contained in engine oils and lubricants in Canada is either chemically transformed or combusted during use of engine and industrial oils or reprocessed into industrial fuels or base oils following collection of waste engine oil. Environmental releases can occur to soil, stormwater and sewage treatment collection systems due to dispersed leaks from vehicle engines to roadways. Additionally, small quantities of both new and used lubricating oils may be improperly disposed of to soil and municipal sewer systems.

The estimated percentages of environmental releases of BNST (expressed as a percentage of the quantity used in Canada) are as follows:

ReleasePercent released
Sewers (due to cleaning of containers used to transport lubricant additives)0.2%
Soil, sewer and stormwater collection (due to use and improper disposal of engine oil and commercial/industrial lubricants)31.3%
Landfill (due to improper disposal of engine oil and commercial/industrial lubricants)0.2%
Air0%

There is no available information on the removal of BNST from wastewater in municipal wastewater treatment facilities. However, based on its chemical properties (high Kow), when discharged to municipal wastewater systems most of this substance will likely partition to collected solid material and the residual sludge produced during the treatment process. Wastewater sludge may then be sent to landfills, incinerated or applied to agricultural soils as fertilizer. Releases to air are not expected, based on a low estimate of volatility.

5.2 Exposure Sources

BNST is not reported to occur naturally. The relatively large quantities of BNST imported into Canada, along with its dispersive uses, indicate the potential for releases to soil and surface water. Because of its resistance to degradation and partitioning behavior, BNST will remain in sediment and soil for long periods after it is released. Exposure of both aquatic and terrestrial organisms to BNST is possible even though the release pattern for this substance indicates extremely dispersed low levels of release. The lipophilic character of BNST indicates that, following exposure, it is likely to bioaccumulate in organisms and may be biomagnified in trophic food chains.

6. Overview of existing actions

6.1 Existing Canadian Risk Management

BNST is not subject directly to any existing Canadian risk management measures, but it is indirectly controlled by existing measures for used crankcase oils (UCOs) and other waste lubricating oils. BNST contributes to the measurable quantity of "oil and grease" that is subject to various federal-, provincial- and municipal-level effluent quality regulations. Since BNST is a constituent of used oils, any measures that act to control releases of used oils would also control releases of BNST. Some existing regulatory measures that control releases of BNST are summarized below:

  • Provinces and territories have put in place risk management measures for UCOs. These include prohibitions for land, landfill and sewer disposal of used oils; permits or approval systems to control burning of used oils; prohibitions or guidelines for use of used oils in dust suppression; controls for used oil reprocessing and re-refinery operations; and programs to collect and manage used oil.
  • The federal Petroleum Refinery Liquid Effluent Regulations specify levels of allowable oil and grease in water discharged to surface water from refineries as defined in these regulations. Ontario also sets specific allowable discharges for certain refineries and chemical manufacturing facilities. The BNST present at petroleum refineries is contained within lubricant additive packages and lubricating oils; therefore, any controls on releases of oil and grease would also limit releases of BNST
  • Municipal sewer use bylaws – Existing limits on the concentration of oil and grease in wastewater discharged to municipal wastewater systems means that releases of BNST due to manufacturing, lubricant blending and industrial use at facilities are effectively controlled.

6.2 Existing International Risk Management

Substituted diphenylamines, including BNST, are part of the U.S. EPA's High Production Volume (HPV) Chemical program, which requires sponsoring companies to provide and make public basic hazard information on the chemical.

Under the European Union REACH Program, BNST was pre-registered in 2008 (as an existing substance, it can continue to be manufactured and imported). By December 1, 2010, manufacturers and importers are required to submit a technical dossier to the European Chemicals Agency containing available information on chemical properties, persistence, bioaccumulation and toxicity.

7. Considerations

7.1 Alternative Chemicals or Substitutes

Substituting BNST with an alternative diarylamine antioxidant is possible; however, significant and costly testing could be required to reformulate in order for any new lubricant product to gain approval (Environment Canada 2009b).

There are several diarylamines identified on the Domestic Substances List. Of these, one substance (CAS 68442-68-2) meets the criteria for categorization under the Chemicals Management Plan (for environmental concerns). Two substances (CAS 101-67-7 and 68411-46-1) did not meet the categorization criteria, but were identified as being a priority for human health assessment. Three of the potential alternatives (CAS 15721-78-5, 36878-20-3 and 68608-77-5) did not meet the categorization criteria, although some of the criteria were noted as "uncertain." All potential alternatives are in the substituted diphenylamine family, and could be subject to a screening assessment at some point in the future.

7.2 Alternative Technologies and/or Techniques

BNST is a very hydrophobic substance that partitions strongly to organic liquids. It is likely to remain within any waste lubricant that is present in any commercially or industrially generated wastewater. Any wastewater treatment that includes removal of free waste oil also removes additives such as BNST (OECD 2004).

7.3 Socio-economic Considerations

Socio-economic factors have been considered in the selection process for a regulation and/or instrument respecting preventive or control actions, and in the development of the risk management objective(s). Socio-economic factors will also be considered in the development of regulations, instrument(s) and/or tool(s) as identified in the Cabinet Directive on Streamlining Regulation (Treasury Board of Canada Secretariat 2007) and the guidance provided in the Treasury Board document Assessing, Selecting, and Implementing Instruments for Government Action.

Based on trends in the lubricants industry, the use of diarylamine antioxidants, including BNST, is expected to increase because of advances in the requirements for gasoline and diesel motor oils. According to research completed by MTN Consulting Services, it could cost in excess of several million dollars to reformulate a lubricant product line to replace BNST with another antioxidant (Environment Canada 2009b).

7.4 Children's Exposure

The Government of Canada considered, where available, risk assessment information relevant to children's exposure to this substance. As part of the Challenge, the Government asked industry and interested stakeholders to submit any information on the substance that may be used to inform risk assessment, risk management and product stewardship. In particular, stakeholders were asked through a questionnaire if any of the products containing the substance were intended for use by children. Given the information received, it is proposed that no risk management actions to specifically protect children are required for BNST at this time.

8. Proposed objectives

8.1 Environmental Objective

An environmental objective is a quantitative or qualitative statement of what should be achieved to address environmental concerns identified during a risk assessment.

The ultimate environmental objective for BNST is virtual elimination (VE). CEPA 1999 requires that substances targeted for VE under section 77 be added to the Virtual Elimination List. A level of quantification (LoQ) shall also be specified as per section 65. The LoQ is the lowest concentration that can be accurately measured using sensitive but routine sampling and analytical methods.

According to CEPA 1999, virtual elimination means, in respect of a toxic substance released into the environment as a result of human activity, the ultimate reduction of the concentration of the substance in the relevant medium below the LoQ specified in the Virtual Elimination List.

8.2 Risk Management Objective

A risk management objective is a target expected to be achieved for a given substance by the implementation of risk management regulations, instrument(s) and/or tool(s). The proposed risk management objective is to achieve the lowest level of release of BNST to the environment that is technically and economically feasible from all life-cycle stages.

9. Proposed risk management

9.1 Proposed Risk Management Instrument

As required by the Government of Canada’s Cabinet Directive on Streamlining Regulation4 and criteria identified in the Treasury Board document entitled Assessing, Selecting, and Implementing Instruments for Government Action, the proposed risk management instrument(s) were selected using a consistent approach, and took into consideration the information that was received through the Challenge and other information available at the time.

In addition, the proposed risk management instrument will be developed in accordance with the principles of public participation as outlined in the Guidelines for Effective Regulatory Consultations developed under the Cabinet Directive on Streamlining Regulation.

In order to achieve the risk management objective and to work towards achieving the environmental objective, the addition of BNST to the Prohibition of Certain Toxic Substances Regulations, 2005 will be considered in order to prohibit the use, sale, offer for sale and import of BNST and products or formulations containing BNST. Although releases from manufacturing facilities are estimated to be small, controls, including a manufacturing prohibition, will be considered as part of the consultation process.

BNST may be considered for addition to the Environmental Emergency Regulations if manufacturing activities involving BNST continue to be permitted.

9.2 Other Information Gathering/Research

Monitoring for BNST in the environment will be conducted under a more comprehensive monitoring and surveillance strategy for all substances that come under the Chemicals Management Plan. Monitoring has been identified as a key pillar in the Chemicals Management Plan, and will serve the following functions: collecting and generating human health and environmental data to inform decision making; providing an adaptive management framework to support intervention; and measuring the efficiency of preventive and mitigation actions.

As part of the Chemicals Management Plan monitoring, it is planned that BNST will be monitored in municipal wastewater, sediment and biota. This monitoring will be used to inform the federal government on releases of BNST to the environment.

9.3 Implementation Plan

One or more risk management measures are intended to be published in the Canada Gazette, Part I, by August 2011.

10. Consultation approach

The risk management scope for BNST, which summarized the proposed risk management under consideration at that time, was published on January 24, 2009. Industry and other interested stakeholders were invited to submit comments on the risk management scope during a 60-day comment period. Comments received on the risk management scope document were taken into consideration in the development of this proposed risk management approach document.

Consultation for the risk management approach will involve publication of the approach on August 1, 2009, and a 60-day public comment period.

The primary stakeholders include

  • the petroleum industry;
  • the chemical manufacturing industry;
  • importers of lubricants and lubricant additives; and
  • environmental non-governmental organizations.

11. Next steps / Proposed timeline

ActionsDate
Electronic consultation on proposed risk management approachAugust 1 to September 30, 2009
Response to comments on the risk management approachAt time of publication of proposed instrument
Consultation on the draft instrumentSummer 2010
Publication of the proposed instrumentNo later than August 2011
Formal public comment period on the proposed instrumentNo later than October 2011
Publication of the final instrumentNo later than February 2013

Industry and other interested stakeholders are invited to submit comments on the content of this proposed risk management approach or provide other information that would help to inform decision making. Please submit comments prior to September 30, 2009 since the risk management of BNST will be moving forward after this date. During the development of regulations, instrument(s) and/or tool(s), there will be opportunity for consultation. Comments and information submissions on the proposed risk management approach should be submitted to the address provided below:

Chemicals Management Division
Gatineau, Quebec  K1A 0H3
Tel: 1-888-228-0530 / 819-956-9313
Fax: 1-800-410-4314 / 819-953-4936
Email: Existing.Substances.Existantes@ec.gc.ca

12. References

[Canada]. 1999. Canadian Environmental Protection Act, 1999. S.C., 1999., ch. 33. Canada Gazette. Part III. Vol. 22, no. 3. Ottawa: Queen’s Printer. Available from: http://www.gazette.gc.ca/archives/p3/1999/g3-02203.pdf

[Canada]. 2000. Canadian Environmental Protection Act: Persistence and Bioaccumulation Regulations, P.C. 2000-348, 23 March, 2000, SOR/2000-107. Canada Gazette. Part II, vol. 134, no. 7, p. 607-612. Ottawa: Queen's Printer. Available from: http://www.gazette.gc.ca/archives/p2/2000/2000-03-29/pdf/g2-13407.pdf

[Canada], Dept. of the Environment, Dept. of Health. 2009. Screening assessment for the Challenge, benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene, Chemical Abstracts Service Registry Number 68921-45-9, Available from: http://www.chemicalsubstanceschimiques.gc.ca/challenge-defi/batch-lot_4_e.html

Environment Canada. 2006. Approach to ecological screening assessments under paragraph 64(a) of CEPA 1999 for existing substances that are both persistent and bioaccumulative. In: CEPA DSL Categorization: Overview and Results [CD-ROM], released September 2006. Environment Canada, Existing Substances Division, Gatineau (QC), K1A 0H3. Available upon request.

Environment Canada. 2008. Data for Batch 4 substances collected under the Canadian Environmental Protection Act. 1999, Section 71: Notice with respect to certain substances identified in the Challenge, published in the November 17, 2007 Notice of intent to develop and implement measures to assess and manage the risks posed by certain substances to the health of Canadians and their environment. Prepared by: Environment Canada, Health Canada, Existing Substances Program.

Environment Canada. 2009a. Assumptions, limitations and uncertainties of the Mass Flow Tool for benzenamine, N-phenyl-, reaction products with styrene and 2,4,4-trimethylpentene, CAS RN 8921-45-9. Environment Canada, Existing Substances Division, Gatineau (QC), K1A 0H3. Internal draft document available upon request.

Environment Canada. 2009b. Non-Confidential Summary of BNST: Use and Disposition in Lubricants. Report prepared by MTN Consulting Associates for Environment Canada, Oil and Gas and Alternative Energy Division, Gatineau (QC), K1A 0H3.

[NCI] National Chemical Inventories [database on a CD-ROM]. 2006. Issue 1. Columbus (OH): American Chemical Society, Chemical Abstracts Service. [cited 2008 Aug 08] Available from: http://www.cas.org/products/cd/nci/require.html

[OECD] Organisation for Economic Co-operation and Development. 2004. Emission Scenario Document on Lubricants and Lubricant Additives. Prepared by the Environment Agency (UK). Available on request from: Environment Canada, Existing Substances Division, Ottawa, K1A 0H3.

Treasury Board of Canada Secretariat. 2007. Cabinet directive on streamlining regulation, section 4.4 [Internet]. Available from: http://www.regulation.gc.ca/directive/directive01-eng.asp


Footnotes

1 CAS RN: Chemical Abstracts Service Registry Number. The Chemical Abstracts Service information is the property of the American Chemical Society and any use or redistribution, except as required in supporting regulatory requirements and/or for reports to the Government of Canada when the information and the reports are required by law or administrative policy, is not permitted without the prior written permission of the American Chemical Society.
2 National Chemical Inventories (NCI). 2007: EINECS (European Inventory of Existing Chemical Substances); and TSCA (Toxic Substances Control Act Chemical Substance Inventory).
3 Estimated release is prior to any removal at municipal wastewater facilities and stormwater retention ponds.
4 Section 4.4 of the Cabinet Directive on Streamlining Regulation states that "Departments and agencies are to: identify the appropriate instrument or mix of instruments, including regulatory and non-regulatory measures, and justify their application before submitting a regulatory proposal".