The Government of Canada conducted a science-based evaluation, called a screening assessment, to address the potential for harm to Canadians and to the environment from 8 of the substances referred to collectively as the Aromatic Amines Group.
Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
As a result of the draft screening assessment, the Government is proposing that, at levels of exposure considered in the assessment:
One substance (dimethylaniline) may be harmful to human health but not to the environment.
The other 7 substances in the Aromatic Amines Group are not harmful to human health or to the environment.
Although 3 of the substances (NDPhA, 2-aminophenol, and MBOCA) are not considered to be harmful at levels of exposure considered in the assessment, these substances have health effects of concern and there may be a potential risk if exposure to these substances were to increase.
About these substances
The screening assessment summarized here focuses on 8 substances, referred to collectively as the Aromatic Amines Group under the Chemicals Management Plan (CMP). These substances are commonly referred to as NDPhA, P1NA, 2-aminophenol, MBOCA, 44PD, dimethylaniline, diphenylamine, and 2-naphthyl anthranilate.
The 8 substances in this assessment do not occur naturally in the environment, except for diphenylamine, which may occur naturally in some food items (such as onions, cheese, and tea).
According to information gathered by the Government, in Canada these substances are used in various applications, including adhesives and sealants, lubricants and greases, munitions, and plastic and rubber materials.
They are also used in applications in the automotive, aircraft and transportation sector.
They may also be used in incidental additives, and in food packaging materials, hair dye, and pest control products.
Human and ecological exposures
Canadians may be exposed to substances in the Aromatic Amines Group mainly from the use of products available to consumers, such as grease and lubricants (for example, motor oils and transmission fluids), certain automotive products (for example, adhesives, automotive body fillers and spray paint primer), hair dyes, children's markers, and textiles (such as clothing).
Canadians may also be exposed to these substances from the environment (for example, air), food, and from use in pest control products.
According to information considered under the ERC Approach, P1NA was identified as having a high ecological exposure potential due to its overall persistence and large annual import quantity according to information reported. The remaining substances in the group were identified as having low to moderate ecological exposure potential.
The United States Environmental Protection Agency classified NDPhA as a probable human carcinogen. Developmental effects were also identified as a critical effect in the assessment. The target organ of concern for both cancer and non-cancer effects is the bladder.
The critical effects identified for P1NA are effects on the blood system, the kidney, spleen and liver.
In the European Union (EU), 2-aminophenol is classified as a mutagen. Additional critical health effects identified include effects on the kidney, liver, as well as decreased body weights and increased thyroid weights.
The critical effects identified for 44PD are effects on the liver and red blood cells.
Dimethylaniline has been classified in the EU as a suspected human carcinogen. Other critical effects identified are effects on the spleen and red blood cells.
The critical health effects identified for diphenylamine are effects on the red blood cells, kidneys, spleen and liver.
2-Naphthyl anthranilate was considered to be of low hazard potential for the human health assessment.
According to information considered under the ERC Approach, 2-aminophenol and MBOCA were identified as having a high ecological hazard potential based on their high potency and possible endocrine receptor binding, respectively. While 44PD, diphenylamine, and P1NA were identified as having a moderate ecological hazard potential based on adverse effects in aquatic food webs given their bioaccumulation potential. The remaining substances were identified as having a low ecological hazard potential.
Risk assessment outcomes
Based upon a comparison of levels to which Canadians may be exposed to substances, and levels associated with critical health effects, it was determined in the draft screening assessment that:
dimethylaniline may pose a risk to human health from exposure to certain automotive products available to consumers; and
the risk to human health from NDPhA, P1NA, 2-aminophenol, MBOCA, 44PD, and diphenylamine is considered to be low.
As a result of the draft screening assessment, the Government is proposing that dimethylaniline may be harmful to human health, at levels of exposure considered in the assessment. It is also proposed that the other 7 substances are not harmful to human health at levels of exposure considered in the assessment.
The Government is also proposing that the substances in the Aromatic Amines Group are not entering the environment at levels that are harmful to the environment.
If the proposed conclusion is confirmed in the final screening assessment, the Government will consider adding benzenamine, N,N-dimethyl- to Schedule 1 of CEPA 1999, also called the List of Toxic Substances, and will consider the following actions to address health concerns:
Regulatory and/or non-regulatory measures to help reduce dermal and inhalation exposures to dimethylaniline contained in certain automotive products such as adhesives, sealants, fillers, primers, and bonding agent, available to consumers in Canada for do-it-yourself projects.
Information is being sought by the Government to inform risk management decision-making. Details can be found in the risk management scope, including where to send information during the public comment period, ending October 14, 2020.
Although NDPhA, 2-aminophenol and MBOCA are not considered to be harmful at levels of exposure considered in the assessment, these substances have health effects of concern based on their potential carcinogenicity or mutagenicity. Therefore, there may be a potential risk if exposure to these substances were to increase.
For this reason, follow-up activities to track changes in exposure or commercial use patterns for NDPhA and 2-aminophenol are being considered.
An analysis of information related to current and potential future uses of MBOCA suggest that it is unlikely that exposure will increase to levels of concern to human health. For this reason, follow-up activities to track changes in exposure and/or commercial use patterns for MBOCA are not being considered at this time.
Stakeholders are encouraged to provide any information pertaining to these substances that may help inform the choice of follow-up activity, during the 60-day public comment period on the assessment. This could include information on new or planned import, manufacture or use of the substances.
Substances in the Aromatic Amines Group may be found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.