Material Safety Data Sheet User's Guide​

10. Toxicological properties

Routes of entry, skin and eye contact Carcinogenicity
Effects of acute exposure to product Reproductive toxicity
Effects of chronic exposure to product Teratogenicity
Exposure limits Mutagenicity
Irritancy and corrosiveness Names of toxicologically synergistic products
Sensitization to product  

Routes of entry, skin and eye contact

This section indicates the routes by which the substance can enter the body and produce harmful effects. These routes include the respiratory tract (inhalation), skin (cutaneous absorption) and the digestive tract (ingestion). Also included is any surface of the body on which the substance can produce a harmful effect by direct contact.

 

Example

· Routes of entry
Toluene
: The substance is absorbed through the respiratory tract, skin and digestive tract.

· Skin and eye contact
Sulfuric acid
: Following direct contact with the skin and eyes, this product may cause burns.


Respiratory tract Digestive tract Skin contact

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Effects of acute exposure to product

These health hazards result from short-term exposure to the controlled product. Acute exposure is generally defined as a single or repeated exposure over a 24-hour period. Often, acute poisoning produces brief and reversible toxic effects. However, some effects may show up only several hours after intoxication. Also, some serious poisonings may produce sequellae.

 

Example

Exposure to high concentrations of acetone vapours (above 12,000 ppm) may cause dryness of the mouth and throat, salivation, anorexia, headache, nausea, vomiting, dizziness, incoordination, asthenia, lethargy and ataxia. In extreme cases, it can lead to stupor or coma.


Acute Effects1 hour Acute Effects 2 hours Acute Effects 3 hours

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Effects of chronic exposure to product

These health hazards result from prolonged
exposure to the controlled product at concentrations
lower than those that produce acute effects.
The duration of the exposure can vary (weeks,
months, years).

 

Example

The repeated inhalation of styrene vapour may cause nervous system disorders that first appear as headache, nausea, dizziness, a loss of appetite, and general weakness. The following effects may subsequently be observed: increased reaction time, difficulty with colour perception, etc. Repeated skin contact with the product may cause redness, desquamation and cracking of the skin.

Chronic exposure - week
Chronic exposure - months

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Exposure limits

Exposure limits are the concentrations permitted in the air for a given substance. They represent the concentrations of the substance in the air to which the great majority of workers can be exposed daily, without suffering harmful effects. There are three types of values:

  • Short-term exposure values, which are measured for a maximum duration of 15 minutes;
  • Time-weighted average exposure values, which are measured for the duration of an 8-hour work shift;
  • Ceiling values, which must never be exceeded for any period of time whatsoever.

On the material safety data sheet, the permissible limit values in Québec, which are specified by the Regulation respecting occupational health and safety (S-2.1, R.19), are sometimes presented. For more details, consult the Regulations (ROHS) section of this guide. However, the limit values recommended by the ACGIH® (American Conference of Governmental Industrial Hygienists), an American organization, are often the ones that appear on the MSDS. Exposure limit values are given in ppm, in mg/m3 or in fibres/cm3.

If a product consists of several ingredients, the exposure limit for each of the ingredients must be indicated on the MSDS.

 

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Irritancy and corrosiveness

This subsection indicates whether the substance may cause irritation of the eyes, skin or mucous membranes of the respiratory and digestive tracts. A substance’s irritating effects on the eyes or skin may be, for example, a minor tingling sensation to erythema (redness) or edema (swelling). This damage is reversible, meaning that it disappears with time, when exposure to the product stops. If the damage caused by a substance is irreversible, the substance is said to be corrosive.

 

Example

Isopropyl alcohol is moderately irritating to the eyes and slightly or not irritating to the skin. Exposure to vapours of this substance may cause irritation of the eyes and upper respiratory tract.

Sodium hydroxide is a corrosive product that may cause serious burns accompanied by deep ulceration of the skin. On the eyes, it causes disintegration and escharification of the conjunctiva and cornea accompanied by edema and ulceration. Permanent opacification of the cornea is also possible. Exposure to dusts or mists may cause irritation and ulceration of the nasal passages. Pulmonary edema may occur with exposures to high concentrations of dusts or mists.

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Sensitization to product

Sensitization is an immune reaction of the body. It occurs following exposure to a chemical or biological substance and produces an allergic response of the respiratory tract (rhinitis, asthma) or skin (eczema). Exposure to the sensitizing substance may have previously produced no symptoms, until an initial allergic response occurs.

 

Example

After an initial contact with isocyanates (TDI, HDI, MDI, etc.), subsequent contact may produce sensitization of the respiratory tract (asthma) in some people.

Formaldehyde (used as a preservative in various types of products such as cutting oils) is a skin sensitizer.

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Carcinogenicity

This subsection specifies whether the substance can cause cancer or not. WHMIS uses the IARC (International Agency for Research on Cancer) and ACGIH® (American Conference of Governmental Industrial Hygienists) classifications to determine a substance’s carcinogenic potential. A substance classified A1 and A2 by the ACGIH, or group 1, 2A and 2B by IARC, is recognized as carcinogenic by WHMIS. Substances can be listed as proven, probable or possible carcinogens, depending on the evidence observed.

 

Example

The International Agency for Research on Cancer (IARC) considers styrene as a possible human carcinogen (group 2B).

 
0 to 5 years 5 to 10 years 10 to 15 years

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Reproductive toxicity

Some substances can have toxic effects on reproduction, meaning that they can cause a change in fertility, thus affecting a woman’s or a man’s reproductive capability. For example, some substances may affect hormonal activity, spermatogenesis, etc., which may affect fertility.

 

Example

Carbon disulfide may cause sperm disorders as well as menstrual disorders in humans.

 

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Teratogenicity

This section states whether the substance can cause malformations in newborns. The Controlled Products Regulations require that all effects on development be mentioned, and therefore embryotoxic and fetotoxic effects (effects other than malformations) must appear on the MSDS. These may include, for example, a reduction in body weight, growth retardation, dysfunction, death, etc. Effects on postnatal development (after birth) are also indicated. Most of the time, the information comes from animal studies.

 

Example

Toluene has an embryotoxic and/or fetotoxic effect on animals.

Teratogenicity

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Mutagenicity

This subsection indicates whether the substance may cause mutations (changes) in the genetic material (DNA) of cells. Mutations in the DNA of reproductive or germ cells (eggs or sperm) may cause hereditary effects, meaning that they are transmissible to offspring. Effects on other cells (nonreproductive or somatic cells) do not cause hereditary effects, but may lead to cell death, the transmission of the mutation to cells of the same tissue, or cancer.

 

Example

Benzene is a human mutagen.

Mutagenicity

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Names of toxicologically synergistic products

These are substances or products that interact with the controlled product to produce a toxic effect greater than the sum of their individual effects.

There are other types of interactions between chemical products, namely antagonism (reduced toxic effects), the additive effect (effects that are added), etc. However, the Controlled Products Regulations do not require that these effects be mentioned on the MSDS.

 

Example

The duration of xylene’s toxic effects increases with the consumption of alcohol or aspirin.

Xylene + Alcohol

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