A Guide to the management hazardous substances

Section 10.3

• Keep a record of all hazardous substances.

Is there a likelihood that the health or safety of an employee may be endangered by exposure to a hazardous substance?

• Yes or No
  
  
  • If yes, the following sections apply:

Section 10.4

• Appoint a qualified person to carry out an investigation.
• Notify the work place health and safety committee or representative.

Section 10.5(a)

• Consult the work place health and safety committee or representative.
• The qualified person writes and signs a report with:
  
  
  1. his observations in accordance with subsection 10.4(2)
  2. his recommendations concerning compliance with sections 10.7 to 10.26 including sampling methods

Section 10.5(b)

• Develop a written safe work procedure.
• Implement procedures to control the concentration or level of the hazardous substance.

Section 10.6

• Keep the report referred to in section 10.5 for 30 years.

Chemical, biological and physical agents

In industrial hygiene:

• a chemical agent is a mist, a vapour, a gas, fumes or dusts of a chemical compound or a mixture of chemical compounds that present a hazard to the health of any person exposed to it.
• a biological agent is an animal, an insect, a parasite or a micro-organism, such as moulds, fungi, viruses, rickettsiae or bacteria, that present a hazard to the health of any person who comes into contact with it.
• a physical agent is an ionizing or non-ionizing radiation, a vibration, a noise and an extreme temperature or pressure that presents a hazard to the health of any person exposed to it.

Controlled products

Section 2 of the Hazardous Products Act (HPA) defines a controlled product as any product, material or substance included in any of the classes listed in Schedule II of the Controlled Products Regulations .

1. Compressed gas
2. Flammable and combustible material
   
   
   1. Flammable gases
   2. Flammable liquids
   3. Combustible liquids
   4. Flammable solids
   5. Flammable aerosols
   6. Reactive flammable materials
3. Oxidizing material
4. Poisonous and infectious material
   
   
   1. Materials causing immediate and serious toxic effects
   2. Materials causing other toxic effects
   3. Biohazardous infectious materials
5. Corrosive material
6. Dangerously reactive material

Controlled products include a large number of chemical substances, mixtures and products used in the work place, as well as various infectious materials.

How is risk assessed?

Risk assessment of a hazardous substance can be based on one or more of the following:

1. judgment of a professional,
2. personal observation, for example by collecting data in the work field,
3. preliminary investigations using direct reading equipment,
4. estimation of the probability that the concentration of an airborne chemical agent or the level of ionizing or non-ionizing radiation exceeds 50 percent of the standards prescribed by the Canada Occupational Health and Safety Regulations,
5. review of the literature on the subject,
6. use of a risk analysis method, like the method proposed by the Canadian Standards Association in CSA Q850-97, and/or
7. study of the hazardous substance's properties, such as toxicity, flammability and chemical reactivity, and of the way in which the material is used, produced, handled or stored. How a substance is used can vary greatly from work place to work place and, therefore, so can the risk level.

If you used the method described in CSA Q850-97, the risk assessment will lead to one of the following three conclusions:

1. The risk associated with the hazardous substance is acceptable.
2. The risk associated with the hazardous substance will be acceptable provided the risk is decreased through elimination, substitution, reduction, monitoring, individual or collective protection, etc.
3. The risk associated with the hazardous substance is unacceptable when the level is higher than the standard, regardless of the level.

In light of the results of the investigation, managers of the work place will have to make decisions and put in place the necessary preventive and corrective measures.

Interpretation

The starting point of any preventive approach is to identify the potential sources of hazards. Therefore, you must keep a record of all hazardous substances found in the work place, that is, chemical, biological and physical agents with at least one property that presents a hazard to the health or safety of any person exposed to them, as well as all controlled products.

It may be that, in your work place, an employee or group of employees uses, produces, handles or stores a hazardous substance with a minimal risk of exposure. Whatever the actual risk level, that hazardous substance must be recorded in the log.

We present here a model of a log that can be easily done electronically in order to facilitate access and modifications. Depending on the size of your establishment, the log can be kept by employee, by workstation, by shop or for the entire work place.

Example of a hazardous substance log (sec. 10.3)

Note 1: The product number might correspond to the number on the material safety data sheet in the case of a controlled product or if the substance is not a controlled product but the MSDS is available. This makes everything easier to manage, especially if you enter this information in a database.

Note 2: Commercial name of the product, name of the substance, common name.

Note 3: Name of the manufacturer or supplier that appears on the container.

Note 4: Work area or work station where the substance or controlled product is used, produced, handled or stored.

Note 5: Is it a controlled product? If so, it would be wise to record the date on which the data sheet was last updated.

Note 6: Use for the substance: function, usefulness, service, use, application …

Note 7: Is a hazard investigation needed in accordance with section 10.4? This information could be very useful because it refers to a file number that will facilitate the research.

Subsection 10.4(1)

If there is a likelihood that the health or safety of an employee in a work place is or may be endangered by exposure to a hazardous substance, the employer shall, without delay:

1. appoint a qualified person to carry out an investigation in that regard; and
2. for the purposes of providing for the participation of the work place committee or the health and safety representative in the investigation, notify either of the proposed investigation and of the name of the qualified person appointed to carry out that investigation.

Interpretation

A hazard investigation must be initiated when the health or safety of an employee or group of employees may be endangered by exposure to a hazardous substance.

Not all hazardous substances found in the work place will require a hazard investigation. An investigation may not be necessary if the health or safety of an employee exposed to a given hazardous substance may not be endangered.

In the following pages, we present four examples of hazardous substances. In the first two cases, spraying of the insecticide Bt and changing transmission oil, it is unlikely that the health or safety of the employee may be endangered. These two substances must appear in the log required under section 10.3, but the investigation referred to in section 10.4 is not necessary.

On the other hand, for UV exposure during arc welding and gun spraying of a paint containing lead chromate, the hazardous substances must appear in the log and the investigation referred under section 10.4 is mandatory.

Example 1: A biological agent

An employee is spraying a liquid insecticide to kill Lepidoptera larvae in a small stand of spruce trees. The active ingredient of this insecticide is a combination of dried spores and protein toxin crystals coming from the bacteria Bacillus thuringiensis subsp. kurstaki. This insecticide is commonly known as Bt. When the buds develop, the employee applies an aqueous base of Bt that will be eaten by larvae. This operation lasts 15 minutes and is always done outside.

Bt is not a controlled product. However, it is a substance governed by the Pest Control Products Regulations , administered by the Pest Management Regulatory Agency. The toxicity of the subsp. kurstaki strain is determined as follows: the oral lethal dose₅₀ (LD ₅₀) in rats is 8,400 mg/kg and the lethal concentration₅₀ (LC ₅₀) after four hours of inhalation in rats is 5,400 mg/m³ . See Appendix A for the definitions of, LD ₅₀ and LC ₅₀.

Even though Bt is fatal for Lepidoptera larvae, it is practically non-toxic for mammals. The U.S. Environmental Protection Agency classifies this pesticide in the "low toxicity" category, compared to a high toxicity substance, which has an LD ₅₀ lower than or equal to 50 mg/kg and an LC ₅₀ lower than or equal to 200 mg/m³ . If we look at the Hodge and Sterner scale (Appendix B), Bt is classified in the very low toxicity category for humans. In addition, this product is non-corrosive, not dangerously reactive, non-combustive, non-flammable, non-teratogenic, non-carcinogenic, non-mutagenic and non-pathogenic.

Since the probability that the health and safety of the employee may be endangered by the exposure to this Bt strain is very low, this hazardous substance must be registered, but the investigation referred to in section 10.4 is not necessary.

Example 2: A chemical agent

A mechanic uses brand 10-OUTOU transmission oil. He does two or three oil changes per week. This product is not controlled.

This oil has an oral LD ₅₀ in rats of over 5,000 mg/kg and a LC ₅₀ by inhalation greater than 5,000 mg/m³ . The threshold limit value for a duration of eight hours (TLV-TWA) is set at 5 mg/m³ for oil mists. Because the vapour pressure of this product is low, there is no risk of inhalation under normal oil change conditions.

In addition, this oil product is non-corrosive, not dangerously reactive, slightly flammable, slightly toxic, non-teratogenic, non-carcinogenic, non-mutagenic and non-pathogenic. During normal use, this oil presents very little hazard to health or safety.

It is unlikely that the health or safety of employees would be endangered by exposure to this transmission oil. Although this product must be recorded in the log, the investigation mentioned in section 10.4 will not be necessary.

Example 3: A physical agent

Passers-by, onlookers and welders are exposed to ultraviolet rays emitted when welding work is performed in a shop. The duration of arc time varies from 30 minutes to two hours. No protective screen has been installed to protect the work area.

Exposing the eye to extremely intense arc light can cause acute ocular disorders. There are two clinical types of acute overexposure: keratoconjunctivitis and electrical dazzle. Radiation from welding arcs can exceed established thresholds in just a few seconds if the person is within a few meters of the arc. These painful effects can result in temporary disablement.

The primary symptoms of keratoconjunctivitis appear when the exposed person complains of severe eye pain, has the feeling of continuously having sand in the eyes, and tries to avoid light (photophobia). The major symptom of electrical dazzle is a blinding sensation, even when the eyes are closed.

There is also a chronic ocular disorder called "diffuse scleritis", which is found mainly in torch welders. This type of scleritis is due to heat and light and is characterized by ocular tension, pain with pressure on the eyes, an excessive constriction of the pupils (miosis) and blurred vision.

Since the frequency of ocular disorders is well documented when proper personal protective equipment is not worn, the type of welding rods used should be recorded in the log and the risk assessment should be conducted according to section 10.4.

Subsection 10.4(2)

In an investigation referred to in subsection (1), the following criteria shall be taken into consideration:

1. the chemical, biological and physical properties of the hazardous substance;
2. the routes of exposure to the hazardous substance;
3. the acute and chronic effects on health of exposure to the hazardous substance;
4. the quantity of the hazardous substance to be handled;
5. the manner in which the hazardous substance is stored, used, handled and disposed of;
6. the control methods used to eliminate or reduce exposure of employees to the hazardous substance;
7. the concentration or level of the hazardous substance to which an employee is likely to be exposed;
8. whether the concentration of an airborne chemical agent or the level of ionizing or non-ionizing radiation is likely to exceed 50 percent of the values referred to in subsection 10.19(1) or the levels referred to in subsections 10.26(3) and (4); and
9. whether the level referred to in paragraph (g) is likely to exceed or be less than that prescribed in Part VI

For your investigation to be in compliance with the COHSR, all the elements appearing in section 10.4(2) must be taken into consideration and appear in the report. See the following table as an example.

Example of hazard investigation (Sec. 10.4)

Interpretation

Following the hazard investigation and after having consulted the work place committee or the health and safety representative, the qualified person must prepare and sign a written report that includes all of his or her observations and recommendations concerning the various factors that were taken into consideration.

The hazard investigation consists of examining all hazardous substances to which employees are exposed in order to:

1. eliminate, substitute, reduce or control them at the source,
2. develop and implement an employee education program aimed at preventing and controlling the hazards,
3. develop a preventive maintenance program for the ventilation systems,
4. ensure that hazardous substances are stored, handled and used in a safe manner,
5. prevent overexposure to ionizing and non-ionizing radiation,
6. develop a safe work procedure for each hazardous substance, and
7. recommend medical examinations for the employees likely to be exposed.

This approach reviews all of the important aspects included in an effective prevention program. It is important to mention that all criteria referred to in subsection 10.4(2) must be addressed in the report. The qualified person must mention whether they are pertinent or not.

Also, sections 10.6 to 10.27 inclusive must be considered in the report. These sections address the following topics:

s. 10.7:

Medical examinations

ss. 10.8 to 10.12:

Storage, handling and use

s. 10.13:

Warning of hazardous substances

ss. 10.14 & 10.15:

Employee education

s. 10.16:

Substitution of substances

ss. 10.17 & 10.18:

Ventilation

ss. 10.19 to 10.22:

Control of hazards

s. 10.23:

Warnings

s. 10.24:

Assembly of pipes

s. 10.25:

Explosives

s. 10.26:

Ionizing and non-ionizing radiation.

Consult the Regulations for the exact text of these sections. The qualified person must mention whether they are applicable to the actual occurrence or not. What follows is an example of recommendations an investigator could make for arc welding.

Important Note: In this example, the stated recommendations concerning the procedure to follow for ensuring compliance with sections 10.7 to 10.26 are not detailed. They cover only the control of exposure to UV and do not address other hazardous aspects of arc welding, such as fumes, noise, burns and electrocution.

Example of recommendations

Model and treatment of an investigation report required by section 10.5

Traditionally, the investigation reports include the following:

• Introductory page.
• Table of contents.
• Context (mandate and objectives) and date of the investigation.
• Methodology used.
• Applicable standards.
• Interpretation of results:
  1. observations concerning the factors taken into consideration in accordance with subsection 10.4(2). See example on page 18.
  2. recommendations concerning the procedure to follow for ensuring compliance with the provisions of sections 10.7 to 10.26, including recommendations concerning sampling and analysis methods. See the example on pages 21 and 22.
• Additional recommendations that might affect the following:
  1. personal protective equipment, such as respiratory protective devices, hearing protectors, protective clothing;
  2. how to make the work procedure safer.
• Conclusion.
• Signature of the qualified person.
• Appendix, such as the industrial hygiene report concerning the assessment of the level of exposure to radiation.

Upon receipt of the recommendations made by the qualified person, the employer must develop and maintain a written procedure for controlling the concentration or level of the hazardous substance present in the work place and train the employees in this procedure.

Interpretation

The requirement to keep the investigation report for 30 years takes into consideration the fact that occupational diseases such as asbestosis, silicosis, byssinosis, siderosis, leukemia and Raynaud's syndrome, can develop after several years of exposure to a hazardous substance, even sometimes after the person is no longer exposed.

For example, when exposed to welding arcs, an employee can develop diffuse scleritis if not properly protected. In addition, some cases of cataracts have been documented after ten years or more of exposure. Consequently, it is very important to keep a record of the investigation report for a sufficient period in order to document the work conditions that may have caused the disorder.

Lethal dose₅₀ or LD ₅₀

The standard term for assessing oral or cutaneous toxicity is the lethal dose₅₀ (LD ₅₀), which means the single dose of a substance that, when administered by a defined route in an animal assay, causes the death of 50% of the animal population. The LD ₅₀ values in humans are only estimated. The LD ₅₀ is usually expressed in terms of milligrams or grams of material per kilogram of body weight for the animal being tested (mg/kg or g/kg).

If we say that a chemical substance has an LD ₅₀ oral on a rat of 300; mg/kg, this means that half of the rats died after stomach intubation of a single dose equivalent to 300 mg per kilogram of rat. Consequently, the lower the LD ₅₀, the more toxic the chemical product.

The LD ₅₀ is used to classify and compare products according to their acute oral toxicity and acute cutaneous toxicity (immediate serious toxic effects).

Lethal concentration₅₀ or LC ₅₀

The lethal concentration₅₀ (LC ₅₀) is the concentration of a substance in air that, when administered by means of inhalation over a specified length of time in an animal assay, causes the death of 50% of the animal population. In the Controlled Products Regulations , the criteria are based on an exposure duration of four hours. The LC ₅₀ is expressed in terms of volume (parts per million or ppm) in the case of gas and vapour, or weight (milligrams of substance per cubic metre of air or mg/m³) in the case of dust, mist or fumes.

A chemical with an LC ₅₀ by inhalation of 2,000 ppm over a four-hour period means that 50% of rats died after inhaling 2,000 ppm of this chemical in the air over four hours. The lower the LC ₅₀, the more toxic the chemical product.

The LC ₅₀ helps in determining the short-term toxic hazard that a substance presents.