Summary of Public Comments received on the Challenge substance isoprene (CAS RN 78-79-5) Proposed Risk Management Approach document for Batch 2

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Comments on the proposed risk management approach for isoprene to be addressed as part of the Chemicals Management Plan Challenge were provided the Learning Disabilities Association of Canada and Dow Chemical Canada.

A summary of comments and responses is included below, organized by topic:

Summary of comments and responses, organized by topic: Cost/benefit Analysis and Risk Management Actions
Topic Comment Response
Cost/benefit Analysis It is critical that all impacts are known and assessed in a cost/benefit analysis before changing the availability or use patterns of a substance. An analysis of benefits and costs will be carefully considered in advance of finalizing the regulation or risk management instrument.
A number of product rubbers are dependent on isoprene although a number of rubbers can be manufactured without isoprene. The critical properties of certain rubber applications and their associated societal uses cannot be delivered by (non isoprene) rubbers. Critical uses of the substance and alternatives are considered in the development of risk management, both from a societal benefit and health risk perspective.
The Pollution Prevention Plan for isoprene is one of the first facility specific instruments being made under the CMP and as such this action will establish a precedent. The group of stakeholders is larger than the limited number of primary stakeholders identified. The Government of Canada strives to identify and engage stakeholders throughout the CMP process. Public comment periods are one way stakeholders may indentify themselves and provide valuable input.
Risk Management actions If actions cannot be taken on consumer products because they fall under other statutes then this should be publicly stated in the screening assessment report. Isoprene was identified to not pose a concern from consumer products as exposure are low to negligible and therefore no action was considered necessary. Where action on consumer products is deemed necessary, consideration is then given as to which federal legislation would be most appropriate to manage the substance.
The maximum residual concentrations should be regulated and migration limits be regulated below the limit of detection, similar to regulations found in the US and Europe to restrict its use in and on foods. In Canada, the use of isoprene as a monomer in isoprene-containing copolymers in food contact applications is controlled under the Food and Drugs Act and its regulations. Evaluation by Health Canada is ongoing to ensure that residual levels of isoprene in finished materials are as low as possible to ensure that potential migration of into food is negligible.
Cigarette smoke should be the prime candidate for the development of control instruments for isoprene. Through a variety of regulations and public outreach programs, the Government of Canada is aiming to reduce the use of tobacco amongst Canadians.
It is suggested a Pollution Prevention plan (if a legal instrument is needed), a Performance Agreement or a negotiated Memorandum of Understanding would be appropriate to address the industrial emissions. A Pollution Prevention Plan for isoprene was published in Canada Gazette Part I on January 1, 2011.
Best Available Technology (or Treatment) Economically Achievable (BATEA) and the approach to minimizing emissions are supportable as there is no evident issue (adverse effect or any impact) surrounding the cited rubber facility. If there was an immediate threat to health or the environment an alternative action may be justifiable. The Pollution Prevention Plan for isoprene controls and/or reduces isoprene stack releases by the application of BATEA.
In the development of a risk management instrument, to be effective, there must be some attempt to understand and partition the relative contribution from natural and man-made sources. If not this may lead to an ineffective instrument. The government’s approach to the management of non-threshold genotoxic substances which have both natural and anthropogenic sources is that anthropogenic sources are additive and avoidable, and, therefore, the approach is to reduce exposure from man-made sources to the extent practicable.
Consideration should be given to adding isoprene to the National Air Pollution Surveillance (NAPS) Network. Isoprene is one of the compounds already monitored as a volatile organic compound as part of the National Air Pollution Surveillance (NAPS) Network.

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