Existing Substances Evaluation: Risk Management Scope 17540-75-9

Risk Management Scope
for

Phenol, 2,6-bis(1,1-dimethylethyl)-4-(1-methylpropyl)-

(2,6-Di-tert-butyl-4-sec-butylphenol (DTBSBP))

Chemical Abstracts Service Registry Number (CAS RN):
17540-75-9

Environment Canada
Health Canada

January 2010

1. Issue

1.1 Draft Screening Assessment Report Conclusion

The substance Phenol, 2,6-bis(1,1-dimethylethyl)-4-(1-methylpropyl)-, Chemical Abstract Service Registry Number (CAS RN)¹ 17540-75-9, referred to throughout this document as “DTBSBP”, is included in Batch 8 of the Challenge under the Chemicals Management Plan. 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). Further to this activity, the Act requires the Ministers to conduct screening assessments of substances that meet the categorization criteria to determine whether these substances meet the definition of “toxic” as set out in section 64 of the Act.

A notice summarizing the scientific considerations of the draft screening assessment report was published for DTBSBP by Environment Canada and Health Canada in the Canada Gazette,Part I, on January 30, 2010, under subsection 77(1) of CEPA 1999. The draft screening assessment report proposes that DTBSBP 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 report also proposes that DTBSBP is not entering the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health.

The draft screening assessment report also proposes that DTBSBP meets the criteria for persistence and bioaccumulation, as defined in the Persistence and Bioaccumulation Regulations made under CEPA 1999 and that its presence in the environment results primarily from human activity.

For further information on the proposed draft screening assessment report conclusion for DTBSBP, refer to the draft screening assessment report, available from http://www.chemicalsubstanceschimiques.gc.ca/challenge-defi/batch-lot-8/index-eng.php. Please note that the conclusions described in this document and in the draft screening assessment report are preliminary and are subject to change.

1.2 Current Canadian Uses and Industrial Sectors

Recent information was collected through surveys conducted for the years 2005 and 2006 under Canada Gazette notices issued pursuant to section 71 of CEPA 1999 (Canada 2006, Canada 2009a). These notices requested data on the Canadian manufacture, import and use of DTBSBP. Three companies reported total importations of between 1000 kg and 100 000 kg of the substance into Canada in 2005 (Environment Canada 2006). In Canada in 2006, no company reported manufacturing of DTBSBP (above the reporting threshold of 100 kg). In 2006, 16 686 kg of DTBSBP was imported into Canada by five companies, including one below the reporting threshold of 100 kg/year. Six companies identified a stakeholder interest (Environment Canada 2009a).

In response to the CEPA section 71 notices, DTBSBP was identified as used in plastics product manufacturing (primarily urethane and other foam products, except polystyrene) and as an antioxidant/corrosion inhibitor used in brake fluid. Other uses were noted to be confidential business information (CBI). Although not described here, this CBI information was considered in estimating environmental releases and in risk management development.

This information is consistent with the DSL nomination data (1984 - 1986), which identified the substance as an antioxidant/corrosion inhibitor/scavenger/antiscaling agent and that the substance was used as an antioxidant in the manufacture of plastics products. It was also used as an antioxidant in other manufactured products (Environment Canada 1988).

The additional information below on potential uses of DTBSBP was found through searches of the available scientific and technical literature, although potential uses in Canada were not specifically confirmed.

DTBSBP is listed by the U.S. Food and Drug Administration as an effective food contact substance, which is any substance that is intended for use as a component of materials used in manufacturing, packing, packaging, transporting, or holding food (US FDA 2008).

It is specifically used as an antioxidant in plasticized vinyl chloride homo- and co-polymers (PVC) (SII 2001). For example, it may be used in PVC films for wrapping meat and produce, and in plastic hoses employed to transfer food during processing and packaging (2009 email from Food Directorate, Health Canada, to Risk Management Bureau, Health Canada; unreferenced).

According to the North American manufacturer of DTBSBP, it is used in the following industries (SI Group 2009):

The purity of commercially available DTBSBP is typically 98.6%. When used as an antioxidant, the concentration of DTBSBP ranges from 0.03-0.10 %wt (SI Group 2009). This substance may also be used as an antioxidant in mineral oils such as turbine oil, hydraulic oil and chain saw oil, in vegetable oils that have replaced mineral oils in some applications due to biodegradability issues, and is being tested for potential needs in bio-diesel (SI Group 2009), though there were no reported uses in these products in the recent section 71 surveys.

It was noted that DTBSBP is being used to replace the antioxidant butylated hydroxytoluene (BHT, CAS RN 128-37-0) in several of the non-food applications listed above (SI Group 2009).

1.3 Releases to the Environment

Results of lifecycle analysis (Environment Canada 2009b) indicate that, overall, 3.7% of the total quantity in Canadian commerce is potentially released in industrial effluents (prior to any treatment) to either surface water or public or private wastewater systems. Releases to air (e.g., from processing and/or weathering) and paved and unpaved surfaces (e.g., from leaks and/or spills) are estimated at 0.4% and 0.2%, respectively. Finally, as DTBSBP is not known to degrade or be consumed during the use of manufactured products, it is estimated that 93.9% of the substance is sent for waste management (landfill, incineration and recycling) from which further releases may be possible. Further details on estimated releases are presented below.

Container Handling and Industrial Releases
To estimate possible industrial releases related to container handling, it was assumed that approximately 3% of the total quantity imported to Canada in drums for use in foam manufacturing, brake fluids and for the confidential use is released to industrial wastewater systems (before any on-site wastewater treatment) as a result of spillage and/or rinsing of drums. Of the total quantity used at facilities manufacturing polyurethane foam and confidential products, it was assumed that between 0.1% and 0.3% may also be released to on-site wastewater systems and between 0.01% and 0.3% may be released to air as a result of manufacturing processes. There is currently no information available concerning the removal of this substance from industrial wastewater effluents, therefore, treatment efficacy is not considered in this analysis.

Foam and Confidential Product Use and Disposal
Of the total quantity of DTBSBP that is contained in foam manufactured in Canada, 0.05% was estimated to be released to public or private wastewater systems and 0.05% released to air as a result of consumer use. The entire remaining quantity (99.9%) is assumed to be sent for waste management (incineration or landfill) following disposal of the products from which further releases may be possible (Environment Canada 2009b).

For the confidential use, it was estimated that of the total quantity of the substance contained in the confidential product, approximately 6% could be released to public or private wastewater systems and 0.05% to air during product use. Approximately 74% is sent for waste management following disposal of products. Further releases following disposal could occur, but are not estimated. An additional assumption regarding the confidential use was that 20% of the product manufactured in Canada was exported and would not result in environmental releases in Canada.

Brake Fluid Use and Disposal
Releases of DTBSBP related to use in brake fluid are assumed during consumer use and disposal of this product. For lifecycle analysis, it was estimated that 1% of the DTBSBP contained in brake fluids in Canada is released to paved/unpaved surfaces (i.e., roads, driveways, parking lots) as a result of spills/leaks during use. It was assumed that half of this amount could be transported into public or private wastewater systems and the other half could remain on road surfaces or soil. In Canada, brake fluids are collected as part of hazardous waste collections systems and the proportion of this waste product sent to recycling facilities was estimated at 99% (Environment Canada 2009b)

Industrial activities, specifically container handling (spillage and/or rinsing of drums) therefore account for the greatest potential for releases to wastewater (3.0%), which may or may not be treated onsite. The greatest potential for releases from use of consumer products is 0.7% to public or private wastewater systems and 0.2% to paved/unpaved surfaces, largely due to releases associated with the use and disposal of brake fluid (Environment Canada 2009b).

Given the types of uses and global production volume, it is probable that the substance is also entering the Canadian market as a component of manufactured items and consumer products. The quantities of DTBSBP released to the environment as a result of use and disposal of products are therefore likely to be higher than those presented in Table 1. It is also recognized that releases from recycling and waste disposal sites may be possible and may contribute to the overall environmental concentration. Currently available information is not sufficient to derive a quantitative estimate for these releases.

1.4 Exposure Sources

DTBSBP is not reported to be naturally produced in the environment. No environmental monitoring data for DTBSBP from Canada or elsewhere has been identified (Canada 2010).

As the effectiveness of sewage treatment operations is unknown, releases of DTBSBP from industrial effluents and public or private wastewater systems may eventually be discharged to surface water. Air emissions associated with industrial processing can lead to atmospheric exposure as the substance tends to remain in air. The substance released to paved/unpaved surfaces during consumer use of brake fluid can be transported to nearby soil or into the sewer, resulting in soil or aquatic exposure. Because of its resistance to degradation and partitioning behavior, DTBSBP will remain in sediment and soil for long periods after it is released. Due to the expected release pattern for this substance, exposure of both aquatic and terrestrial organisms to DTBSBP is possible. The lipophilic character of DTBSBP indicates that, following exposure, it is likely to bioaccumulate in organisms and may be biomagnified in trophic food chains (Canada 2010).

Evaluation of risk to human health involves consideration of data relevant to estimation of exposure (non-occupational) of the general population, as well as information on health hazards. The draft assessment report indicated that human exposure to DTBSBP through dietary intake, if any, in Canada would be minimal. The general population may be exposed to DTBSBP used in polyurethane foam products in bedding, furniture and automotive trim materials (Chinn et al. 2006, Meyer-Ahrens 2005) and possibly plasticized PVC for food packaging applications (2009 email from Food Directorate, Health Canada, to Risk Management Bureau, Health Canada; unreferenced). Based on the information available, the margins between upper-bounding estimates of exposure through food (i.e. migration from food packaging) and consumer products and levels associated with effects in experimental animals are considered to be adequately protective of human health (Canada 2010).

2. Overview of Existing Risk Management

2.1 Existing Canadian Risk Management

Currently, there are no known risk management measures related specifically to DTBSBP in Canada for health or environmental concerns. Used brake fluids (some of which may contain DTBSBP) are already collected and managed as hazardous waste in some provinces, territories and municipalities.

The safety of all materials used for packaging foods is controlled under Division 23 of the Food and Drugs Act and Regulations, Section B.23.0001 of which prohibits the sale of foods in packages that may impart harmful substances to their contents. Because of the general nature of this requirement, and in the absence of positive lists delineating permitted ingredients, packaging materials intended for use with foods may be submitted voluntarily to the Food Directorate for a premarket assessment of their chemical safety in relation to Section B.23.001. This applies to any type of material, whether it is in the form of a finished product such as a laminated film, a container, etc (Canada 2009b).

2.2 Existing International Risk Management

DTBSBP is included in the U.S. EPA’s Toxic Substances Control Act inventory and is a sponsored chemical ² on the High Production Volume (HPV) Challenge.

DTBSBP is listed by the U.S. Food and Drug Administration (FDA) as an effective food contact substance subject to FDA Code of Federal Regulations Title 21,section 175.105 (US FDA 2009) as an antioxidant at a maximum concentration of 0.06% by weight of the finished polymer in PVC under certain conditions of use (US FDA 2008).

DTBSBP is present on the European Inventory of Existing Commercial Chemical Substances as a Low Production Chemical. It is considered hazardous per the Safety Data Sheets Directive (91/155/EC) as amended, with EU symbols Xi – Irritant and N – Dangerous for the environment.³

DTBSBP is also included on the Oslo-Paris (OSPAR) Commission’s list of substances of possible concern. Although OSPAR lists the functional use category of DTBSBP as a pesticide, it is further stated that there is no authorized use in the European Union in plant protection products (OSPAR 2006). It is not registered for use as a pesticide active ingredient (PMRA 2009) or formulant in Canada (PMRA 2007).

3. Proposed Risk Management

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 to recommend addition to the List of Toxic Substances and, where applicable, recommend the implementation of virtual elimination . In this case, the Ministers proposed to recommend the addition of DTBSBP to the List of Toxic Substances in Schedule 1 and to implement virtual elimination. 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 will provide a conclusion as to whether or not DTBSBP meets the virtual elimination criteria set out in subsection 77(4) of CEPA 1999. If the following criteria are met, virtual elimination will be implemented:

In this case, the risk management will be based on the environmental objective of eliminating the release of the substance to the environment. In order to achieve this objective, potential risk management actions could include measures to eliminate release in industrial effluents from facilities manufacturing, processing or using DTBSBP and/or to prohibit the use of DTBSBP in products manufactured, imported, used, sold or offered for sale in Canada. The Government of Canada will follow the process specified in CEPA 1999 for substances that meet the criteria for virtual elimination. In accordance with the Government of Canada’s Toxic Substances Management Policy, socio-economic factors will be taken into account when determining interim targets, appropriate management approaches and timelines for implementation.

If the final screening assessment report does not conclude that DTBSBP meets the conditions set out in subsection 77(4) of CEPA 1999, DTBSBP will not be subject to the virtual elimination provisions under CEPA 1999. Instead, DTBSBP will be managed using a life-cycle approach.

In accordance with the Government of Canada’s Cabinet Directive on Streamlining Regulation⁴ (TBS 2007), the proposed risk management regulation(s), instrument(s) or tool(s) will be selected using a thorough, consistent and efficient approach and take into consideration the information that has been received through the Challenge and other information available at this time.

4. Next Steps

Industry and other interested stakeholders are invited to submit comments on the content of this risk management scope or other information that would help to inform decision making. Although all submitted information will be considered, specific information of the type described below would help to address uncertainties and inform decision making:

DTBSBP is considered part of a broader category of substances known as alkylphenols (US EPA 2009) that are commonly used as anti-oxidants and chemical intermediates. Some substances in this same broad category of substances will be subject to assessment in an upcoming phase of the Chemicals Management Plan. It would therefore be important for stakeholders to identify at this time whether potential alternatives to DTBSBP would also be considered part of the alkylphenols category.

Please submit comments prior to March 31, 2010, since the proposed risk management approach for DTBSBP will be developed after this date. The proposed risk management approach will be released approximately six months after the release of this risk management scope, simultaneously with the publication of the final screening assessment report. There will be opportunity for further consultation at that time. Comments and information submissions on the risk management scope should be submitted to the address provided below:

Program Development and Engagement Division
Gatineau QC K1A 0H3
Tel: 1-888-228-0530 / 819-956-9313
Fax: 819-953-7155
Email: Existing.Substances.Existantes@ec.gc.ca

5. References

Canada, 1999. Canadian Environmental Protection Act, 1999. S.C. 1999, c. 33. Canada Gazette. Part III. vol. 22, no. 3. Ottawa: Queen’s Printer. Available from: http://laws-lois.justice.gc.ca/eng/C-15.31/index.html

Canada, Dept. of the Environment, 2006. Canadian Environmental Protection Act, 1999: Notice with respect to selected substances identified as priority for action. Canada Gazette, Part I, vol. 140, no. 9, p. 435–459. Available from: http://www.ec.gc.ca/Ceparegistry/documents/notices/g1-14009_n1.pdf

Canada, Dept. of the Environment, 2009a. Canadian Environmental Protection Act, 1999: Notice with respect to Batch 8 Challenge substances. Canada Gazette, Part I, vol. 143, no. 5, p. 196–213. Available from: http://www.gazette.gc.ca/rp-pr/p1/2009/2009-01-31/pdf/g1-14305.pdf

[Canada] Environment Canada, Health Canada. 2010. Draft Screening Assessment for the Challenge, Phenol, 2,6-bis(1,1-dimethylethyl)-4-(1-methylpropyl)-(2,6-Di-tert-butyl-4-sec-butylphenol (DTBSBP)), Chemical Abstract Service Registry Number (CAS RN) 17540-75-9. Available from: http://www.chemicalsubstanceschimiques.gc.ca/challenge-defi/batch-lot-8/index-eng.php

Environment Canada. 1988. Data relating to the Domestic Substance List (DSL) 1984-1986, collected under CEPA, 1988, s. 25(1). Collected according to: Reporting for the Domestic Substance List [reporting guide], Minister of Supply and Services Canada, DSS cat. no. En40−364/1998E. Prepared by: Environment Canada, New Substances Division.

Environment Canada. 2006. Data for selected substances collected under the Canadian Environmental Protection Act, 1999, Section 71: Notice with respect to selected substances identified as priority for action. Prepared by: Environment Canada, Health Canada, Existing Substances Program.

Environment Canada. 2009a. Data for Batch 8 substances collected under Canadian Environmental Protection Act, 1999,. Section 71: Notice with respect to Batch 8 Challenge substances. Data prepared by: Environment Canada, Existing Substances Program.

Environment Canada, 2009b. Mass Flow Tool Report for Phenol, 2,6-bis(1,1-dimethylethyl)-4-(1-methylpropyl) or DTBSBP, CAS RN 17540-75-9. Internal draft document. Gatineau (QC): Environment Canada, Existing Substances Division.

Health Canada, 2009. Email from Food Directorate, to Risk Management Bureau, Health Canada; unreferenced

OSPAR Commission, 2006. OSPAR List of Substances of Possible Concern [Internet]. Reykjavik (IS): OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic, Hazardous Substances, The .OSPAR List of Substances of Possible Concern, (last updated August 2006), Reference No. 2002-17. [cited 2009 June 29]. Available from: http://www.ospar.org/eng/html/welcome.html or http://www.ospar.org/v_substances/get_page.asp?v0=17540759.xls

[PMRA] Pest Management Regulatory Agency. 2007. Memorandum to Pesticide Registrants. Post-categorization of substances on the Domestic Substances List: Impacts of the Challenge for Pesticide Registrants. Attachment 1: Actives, Formulants and Formulant Impurities on the Challenge List Resulting from Categorization of the DSL [Internet]. Ottawa (ON): Health Canada, Pest Management Regulatory Agency. [cited 2009-10-26]. Available from: http://www.hc-sc.gc.ca/cps-spc/pest/registrant-titulaire/prod/_memo-note/impact-attach-consequ-piece-ajointe-eng.php

SI Group, 2009. Information submitted to Environment Canada, Program Development and Engagement Division under the Chemicals Management Plan Challenge initiative. Gatineau, QC.

[SII] Schenectady International, Inc. (now called SI Group) 2001. Alkylphenols Category. Section One, Development of Categories and Test Plans, Chemical Right to Know Initiative, HPV Challenge Program. Report submitted to US Environmental Protection Agency, Office of Pollution Prevention and Toxics, HPV Challenge Program, Washington, D.C. 40 pp. Available from: http://www.epa.gov/hpv/pubs/summaries/alkylphn/c13007rt.pdf

[US FDA] United States Food and Drug Administration, 2008. Inventory of Effective Food Contact Substance (FCS) Notifications: FCN No. 80. [Internet]. Washington (DC): U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Food Additive Safety. [cited 2008 April]. Available from: http://www.cfsan.fda.gov/~dms/opa-fcn.html

Footnotes

¹CAS 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.
²http://www.epa.gov/oppt/chemrtk/pubs/update/spnchems.htm
³ SI Group MSDS for ISONOX® 132
⁴Section 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.”

Disclaimer: Although care has been taken to ensure that the information found on this website accurately reflects the requirements prescribed in the Canadian Environmental Protection Act (1999), you are advised that, should any inconsistencies be found, the legal documents, printed in the Canada Gazette, will prevail.

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