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 4 substances in the Carboxylic Acids 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 screening assessment, it was concluded that none of the 4 substances in the Carboxylic Acids Group are harmful to human health or the environment, at current levels of exposure.
About these substances
The screening assessment focused on 4 substances referred to collectively under the Chemicals Management Plan (CMP) as the Carboxylic Acids Group. The substances are commonly referred to as propionic acid, n-butyric acid, nonanoic acid, and oxalic acid.
According to information gathered by the Government, these substances are used commercially in Canada in a number of applications, including use as processing aids, in plastic and rubber materials, in industrial manufacturing processes, lubricants, solvents, and non-pesticidal agricultural products. All 4 are approved pesticide formulants for use in pest control products in Canada.
The substances in this group are naturally occurring compounds that are present in a variety of foods (for example, fruits, vegetables, meats, or dairy products). Propionic acid is an approved food additive for use in Canada as a preservative, while propionic acid, n-butyric acid, and nonanoic acid may be used in Canada as food flavouring agents.
Propionic acid and oxalic acid may be used in the manufacture of some food packaging materials. Nonanoic and oxalic acid may be used as components in sanitizers and cleaners for use in food processing establishments.
Nonanoic acid is also used in cosmetics, and both nonanoic acid and oxalic acid are used as ingredients in other products available to consumers. All 4 substances in this group can be used as ingredients in natural health products.
Human and ecological exposures
Canadians may be exposed to these substances from their natural occurrence in the environment (for example, in air) and in foods.
Canadians may be exposed to nonanoic acid from certain cosmetic products (for example, eye make-up) and a liquid disinfectant product, while exposure to some of these substances (that is, those present in licensed products) may occur from their use in natural health products.
The main source of dietary exposure to oxalic acid is from its natural occurrence in plants. Exposure may also occur from its use as an ingredient in cleaning products available to consumers.
According to information considered under the Ecological Risk Classification of organic substances approach, n-butyric acid, nonanoic acid, and oxalic acid were identified as having low ecological exposure potential. Propionic acid, however, was identified as having a high ecological exposure potential based on quantities reported to the Government and its long range transport potential.
Key health and ecological effects (hazard)
To identify effects of concern for human health, international reports of data on these substances were reviewed.
Propionic acid and n-butyric acid have been assessed by the the Organisation for Economic Cooperation and Development (OECD) Cooperative Chemicals Assessment Programme. The Screening Information Data Set (SIDS) and SIDS Initial Assessment Reports (SIARs) are available.
Propionic acid has also been assessed by the European Food Safety Authority (EFSA) and nonanoic acid has been assessed by the European Chemicals Agency (ECHA). These noted assessments were used to inform this screening assessment.
On the basis of these existing international assessments, propionic acid, n-butyric acid, and nonanoic acid are considered to be substances of low human health hazard potential.
Available information indicates that oxalic acid may have potential effects on the reproductive system. This was considered to be the important or "critical" effect used for characterizing the risk to human health in the assessment of this substance.
According to information considered under the Ecological Risk Classification of organic substances approach, all 4 substances in this group were identified as having low ecological hazard potential.
Risk assessment outcomes
On the basis of the information presented in the screening assessment, propionic, n-butyric, and nonanoic acid are considered to be substances with low hazard properties, and therefore, the risk to human health is low.
Based upon a comparison of levels to which Canadians can be exposed to oxalic acid and levels associated with health effects, the risk to human health from this substance is also low.
Based upon the outcome of the Ecological Risk Classification of Organic Substances Approach, all 4 substances are considered unlikely to cause ecological harm.
As a result of the assessment, the Government concluded that propionic acid, n-butyric acid, nonanoic acid, and oxalic acid are not harmful to human health at current levels of exposure.
The Government also concluded that these 4 substances are not entering the environment at levels that are harmful to the environment.
Related information
These substances may be found in products available to consumers. Canadians should follow any safety warnings and directions on product labels and dispose of products responsibly.
Visit Healthy Home for more information on chemical safety in and around the home.
Canadians who may be exposed to these substances in the workplace should consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
