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 screening assessment, the Government concluded that
these 21 substances are not harmful to human health or to the environment
at current levels of exposure. Three of the substances (silicon carbide CAS RN 409-21-2, molybdenum oxide CAS RN 1313-27-5, and beryllium CAS RN
7440-41-7) are associated with human health effects of concern; however,
the risk to Canadians was determined to be low at current levels of
About these substances
The screening assessment summarized here focuses on 21 substances that
were identified under the Chemicals Management Plan (CMP) as being of low concern to both human health and the environment,
using 4 different streamlined science approaches, as noted below.
The human health risks of these 21 substances were characterized and
published in one of the following human health science approach
The biomonitoring-based approach 1 considers substances to be of low concern for human health when
biomonitoring data indicates that exposure to Canadians from the
substance is limited or unlikely.
The biomonitoring-based approach 2 considers substances to be of low concern for human health when
biomonitoring data indicates that exposure to Canadians is below
the biomonitoring guidance values (health effects) that are
protective of human health.
The low human health hazard potential approach considers substances to be of low concern when there is
sufficient hazard data to indicate that human health effects are
limited or unlikely.
The human health exposure and risks were characterized using 2 science
approaches based upon biomonitoring data. Human biomonitoring is the measurement of substances in blood, urine or breast milk through
health studies or surveys. The information on measured levels in humans
is important to estimating exposure to Canadians.
Three substances were characterized in the biomonitoring-based
approach 1, and they are considered to have limited or unlikely
exposure to Canadians.
Thirteen substances were characterized in the biomonitoring-based
approach 2, and the exposure to Canadians is considered to be below
the biomonitoring guidance values.
Silicon carbide (CAS RN 409-21-2) as being possibly carcinogenic to
Molybdenum oxide (CAS RN 1313-27-5) as being possibly carcinogenic
to humans, based upon occupational exposure to the substance
through steel production
Beryllium (CAS RN 7440-41-7) as being carcinogenic to humans, based
upon occupational exposure to beryllium or beryllium compounds
IARC has classified fibrous silicon carbide as possibly carcinogenic to
humans; however, at the time of the screening assessment, only
non-fibrous sources were used in Canada. Non-fibrous silicon carbide
was determined to be of low concern for human health based upon the low
human health hazard potential approach.
For these 21 substances, ecological hazard was characterized in the
ERC-I approach, using information from past domestic and international
assessments and water quality guidelines. When no suitable hazard data
were available, multiple sources of information were consulted to
derive predicted no-effect concentrations.
Risk assessment outcomes
Using the 3 human health science approaches, these 21 substances were
characterized as being of low concern for human health.
Using the ERC-I approach, these 21 substances were characterized as
having low ecological concern.
The Government concluded that these 21 substances are not harmful to
human health, and are not entering the environment at levels that are
harmful to the environment.
Preventive actions and reducing risk
Although these substances are not considered to be harmful to human
health at current levels of exposure, 3 of the substances (silicon
carbide, molybdenum oxide, and beryllium) are considered to have health
effects of concern based upon their potential carcinogenicity.
Therefore, there may be a potential risk for human health if exposures
were to increase.
For this reason, the Government will undertake information gathering
activities to track changes in exposure and use patterns for silicon
Available information on current and potential future uses of
molybdenum oxide and beryllium does not suggest a likelihood that
exposures will increase to levels of concern to human health. For this
reason, specific follow-up activities to track changes in exposure
and/or commercial use patterns for these substances are not being
considered at this time.
These substances 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.