Under 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.
As a result of the draft screening assessment, the 4 substances in the Ethers Group are proposed not to be harmful to human health or to the environment at levels of exposure considered in the assessment.
About these substances
The screening assessment summarized here focuses on 4 substances: ethane, 1,1'-oxybis-; benzene, 1,1'-oxybis-; methane, oxybis-; and propanol, 1(or 2)-(2-methoxymethylethoxy)-, also referred to as diethyl ether (DEE), diphenyl ether (DPE), dimethyl ether (DME) and dipropylene glycol methyl ether (DPGME), respectively. They were assessed under the Chemicals Management Plan (CMP).
DEE, DPE and DME naturally occur at low levels in some foods, but DPGME does not occur naturally in the environment.
According to information gathered by the Government, these substances are mainly used in Canada in air care, automotive, aircraft and transportation, cleaning and furnishing care, fuels and related products, oil and natural gas extraction, as well as paints and coatings. They may be used in food packaging materials, food processing aids, food flavouring agents, medicinal or non-medicinal ingredients in disinfectant, human or veterinary drug products and natural health products, cosmetics, various other products available to consumers, and as formulants (inactive ingredients) in pest control products.
Human and ecological exposures
Canadians may be exposed to substances in the Ethers Group from environmental media and food. The general population may also be exposed to these substances from the use of products available to consumers; for example:
DEE from the use of body lotions, corn and callus removers, and automotive starting fluids
DPE from air fresheners and hand creams
DME from spray sunscreens
According to the information considered under the ERC Approach, DEE, DPE and DPGME were identified as having low ecological exposure potential. DME, however, was classified as having a high ecological exposure potential based on a long overall persistence and a large annual import quantity.
A comparative approach using similar chemicals, called read-across, was used to inform the human health assessment to address some limitations in the dataset.
The critical effects for DEE were body weight changes, liver toxicity and decreased survival rates in rats exposed to high oral doses. Changes in body weight were noted as the main critical effects for oral and long-term inhalation exposure to DPE. The critical effect for DME was decreased survival rates in rats exposed via long-term inhalation. DPGME was not identified as inducing any adverse effects in any of the available studies and is considered to be of low hazard potential.
According to information considered under the ERC Approach, all 4 substances were identified as having a low ecological hazard potential.
Risk assessment outcomes
On the basis of the information presented in the draft screening assessment, the risk to human health from the 4 substances in the Ethers Group is low.
Based upon the outcome of the ERC Approach, these 4 substances are considered unlikely to be causing ecological harm.