Summary of public comments received on draft screening assessment - benzenesulfonic acid, 4-methyl- or p-toluenesulfonic acid

The submitter indicates that direct disposal of PTSA into the environment would have detrimental effects, and that regulations should be followed by industry to avoid this.

The submitter is also in agreement with the conclusion that there is low risk of harm to the environment from PTSA based on the available data; however, additional studies on the environmental fate of PTSA are required. In particular, studies are needed on the breakdown of PTSA in the presence of water, and consideration given to the toxicity of its breakdown products to aquatic life.

The ecological risk classification of organic substances (ERC) approach was used to characterize exposure to the environment from PTSA. As a risk-based approach, the ERC considers multiple metrics for both hazard and exposure, with weighted consideration of multiple lines of evidence for determining risk classification. Several lines of evidence were considered in determining the potency of the substance and potentials for exposures in a variety of media.

Furthermore, the ERC approach considers a range of information such as half-lives in environmental media and bioaccumulation potential. However, on the basis of low exposure classifications according to information considered under ERC, PTSA was identified as having a low potential for ecological risk. Therefore, there was no further investigation of its environmental fate or its environmental degradation products.

The submitter is in agreement with the conclusion of this risk assessment that, based on the available data, there is low potential of harm to human health from PTSA; however, additional information on the human health effects and exposure should be added to address the topics below.

Additional references were provided for consideration, describing acute toxicity, corrosivity, and breakdown of PTSA. The human health effects of breakdown products of PTSA in the presence of moisture should be considered, including the potential to cause cancer.

Repeated inhalation of aerosols from perfumes and other cosmetics and from paints containing PTSA could cause serious health effects. The submitter suggests that PTSA should be replaced with substitutes in these products.

Since PTSA is used as an additive in food packaging, more data, such as cytotoxicity test data, are required to confirm if PTSA or its breakdown products leach from food packaging.

Health effects to workers from occupational exposure to PTSA should be considered.

Additional information submitted was considered; however, no changes were made to the screening assessment. The references cited in the comments did not provide additional human health data beyond those that had already been considered in the screening assessment. PTSA was considered to be of low risk to human health.

The highest exposure of PTSA from repeated inhalation of aerosols was assessed from its use in conversion varnish spray products and when compared to potential health effects, the risk to human health was considered to be low. Based on available data, PTSA in aerosol formulations in cosmetics was not identified as a use in Canada. Given that PTSA is not identified to be of concern to human health or the environment, reduction of exposure to it through substitution or other risk management measures is not being considered.

Migration of PTSA from food packaging materials was considered in the assessment and determined to be negligible. Further data are not expected to inform the conclusion of the screening risk assessment that PTSA is not of a human health concern.

Human health assessments focus on risks of exposure to the general population, rather than risks of exposures in the workplace. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System (WHMIS).

The Government of Canada is working with the provinces and territories to explore ways to enhance the protection of workers from exposure to chemicals by integrating and leveraging the information, tools, and/or technical expertise of the Chemicals Management Plan and Health Canada’s Workplace Hazardous Products Program.