Of the 18 substances assessed in Batch 4, two pose a risk to human health and one poses a risk to the environment.

The Government is recommending two of the substances that pose a risk to human health, dimethyl sulfate and diethyl sulfate, and the one substance that poses a risk to the environment, benzenamine, also known as BNST, be added to Schedule 1 of the Canadian Environmental Protection Act (CEPA), 1999. The Government is also recommending BNST for virtual elimination

Dimethyl sulfate and diethyl sulfate are controlled under existing legislation such as the Hazardous Products Act, and are subject to reporting under the National Pollutant Release Inventory. To keep Canadians' exposure low, the Government is also recommending a future use notification provision be added to both of these substances so that they cannot be used for any new activity without undergoing a thorough health and environmental assessment.

Dimethyl sulfate is used in Canada in the manufacture of substances which are then used in pharmaceuticals. It is also used in the production of dyes, fragrances and water/sewage treatment flocculants.

Diethyl sulfate is mainly used in Canada by the tissue paper industry as a softener. It may also be used to make products used in the manufacture of dyes, fragrances, agricultural chemicals, pharmaceuticals, and textiles.

Two other substances (butane and isobutane containing 0.1% 1,3-butadiene) are harmful to health because of the presence of 1,3-butadiene. Because exposures are very low and 1,3-butadiene is already included on Schedule 1 of CEPA, 1999 the Government is recommending the risk management strategy for 1,3-butadiene be updated to include this new information, but no additional risk management actions for butane and isobutane containing 1,3-butadiene will be taken at this time. Butane and isobutane will be assessed separately as part of the Government's medium priorities.

BNST is used as an antioxidant in automotive oils as well as in commercial and industrial lubricants. It is harmful to the environment because it stays in the environment for a long time and builds up in aquatic organisms and wildlife. Significant amounts of BNST may enter sewer systems as a result of dispersed leaks of engine oil to roadways through use of vehicles and due to improper disposal of waste lubricating oils.

The proposed risk management approach to prevent future releases of BNST to the environment is to recommend BNST for virtual elimination and to add BNST to the Prohibition of Certain Toxic Substances Regulations, 2005. This measure will prevent the use of BNST in lubricating oils that have the potential for dispersed release.

Of the remaining 13 substances in Batch 4, five have hazardous properties but are not considered a concern because they are not currently used or are used in low quantities in Canada. To keep these five substances from being reintroduced to the Canadian market prior to further assessment, Significant New Activity (SNAc) provisions are recommended. These provisions will allow the Government to be notified of any new use of these substances and to conduct additional ecological and human health risk assessments. No further action will be taken on the remaining eight substances.

The Government's conclusions in the screening assessment reports are final. The Government will also release proposed risk management approaches. Stakeholders are encouraged to provide comments on the Government's recommended risk management activities until September 29, 2009. The information provided by stakeholders during the public comment period will help to determine the best approach to managing these substances.

Under the Chemicals Management Plan, legacy chemicals that have not previously undergone rigorous scientific assessment in Canada are being addressed. The Government is challenging industry and other stakeholders (academics and non-governmental organizations) to provide information on approximately 200 high-priority substances and how they are currently used in Canada. This is known as the Challenge.

Beginning in February 2007, and about every three months, profiles of 12 to 20 of these chemical substances are released. Four months (or up to six, with written request) are given for stakeholders to respond, after which time, government scientists review all the information provided. The draft screening assessment reports and risk management scopes are the first stage in reviewing the information provided. From this information, possible adverse effects on the environment and human health are determined, and substances that may require risk management are identified.

A 60-day public comment period is provided in the legislation following publication of the draft assessment. Any new information provided is considered and incorporated into the final assessment, which is published four months after the close of the public comment period. Management of the concerns identified in the assessment is implemented as outlined in CEPA, 1999.