• Bruce LevittChemical Routes of Entry

    Working with chemicals can involve the risk of exposure, becoming hazardous to a person’s health. Those health risks are dependent upon the toxicity of the chemical, the types of effects, and how the chemicals enter the body.

    There are four major routes of entry chemicals can follow:

    • Inhalation (breathing)
    • Absorption (skin contact)
    • Ingestion (eating)
    • Injection

    The most common way workplace chemicals enter the body is by breathing. Other chemicals can be absorbed through the skin into the bloodstream. They can also be accidentally swallowed if hands or cigarettes are contaminated. Contaminated cigarettes also pose an inhalation risk, which can be elevated since the cigarette is heating and/or vaporising the chemical contaminant. Of course, workers should never eat, drink or smoke in areas where they may be exposed to toxic chemicals.

    Injection is another way that chemicals enter the body. Though less common in most workplaces, it can occur when a sharp object (e.g., a needle) punctures the skin and injects a chemical (or virus) into the bloodstream. This can also occur when a chemical is sprayed at the body at high pressure.

    Particles are inhaled to the lungsEyes are also another route of entry, although usually only very small amounts of chemicals in the workplace enter through the eyes or mouth.

    However the chemical enters the body, it is distributed throughout the body via the bloodstream, where they can attack and harm organs which are far away from the original point of entry as well as where they entered the body.

    To prevent harmful health effects, take steps to eliminate or reduce the hazard. Control at the source, such as substitution with a less hazardous material or industrial process, is the best method. Bear in mind the specific hazards of the material and the extent and pattern of exposure.

    Some preventative measures include:

    Engineering Controls (isolating or removing the hazard):

    • Enclose process,
    • Provide local exhaust

    Administrative Practices

    • Time work so fewer workers are exposed,
    • Work upwind of mixing operations,
    • Shower after shift
    • Change clothes
    • No food or smoking in work areas

    Personal Protective Equipment

    Eye Protection

    Depending on the job you are doing and the type of material you are handling, you may need various levels of eye protection (e.g. safety glasses, chemical safety goggles, a face shield or some combination of these).

    Skin Protection

    Skin protection includes items such as gloves, aprons, full body suits, and boots. The MSDS should tell you the types of materials that provide the best protection against the product you are using. No one material acts as a barrier to all chemicals. It is also important to consider the temperature conditions and the need for materials not easily cut or torn.

    Respiratory Protection

    There are several types of respirators on the market. Some are effective against some chemicals but may provide little or no protection against others. Selecting the best respirator for you can be quite complicated.

    A qualified person must carry out a detailed assessment of the workplace, including all chemicals used and their airborne concentrations and forms. Consequently, complete respiratory protection guidelines generally cannot be given on the MSDS. If respirators are required at your work site, a complete respiratory protection program including respirator selection, fit testing, training and maintenance is necessary. Levitt-Safety’s | EHS Training & Consulting department can provide all of these services – call us today for more information.

    Material Data Safety Sheets (MSDS)

    A material safety data sheet (MSDS), or safety data sheet (SDS), is an important component of occupational health and safety. It’s intended to provide workers and emergency personnel with procedures for handling or working with a hazardous substance in a safe manner, and includes information such as physical data (melting point, boiling point, flash point, etc.), toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill-handling procedures.

    You should check that the description (physical state and appearance) of the material on the MSDS is the same as the material you have. If it isn’t, you may not have the correct MSDS. Alternatively, the material may be old or may have decomposed during shipping or storage. In either case, the information on the MSDS may not apply, and you should obtain additional advice.

    Acute and Chronic Effects of Workplace Hazards

    Workplace hazards can have serious effects on the body, both immediate and long-term, referred to as acute and chronic.

    Acute effects appear immediately after exposure to high levels of a toxic substance and may be treatable. The sudden collapse of a worker after being exposed to carbon monoxide, for example, is an acute effect.

    Chronic effects become apparent only after many years and by and large, are not treatable. They can occur when the body attempts to repair itself or compensate for acute effects of a substance. For example, cancer is a chronic effect, as is the lung scarring caused by silica dust or the hearing damage caused by excessive noise. Chronic disease becomes evident only after severe damage has occurred.

    Exposure limits have been developed for various hazardous materials to protect workers, but they should not be treated as a fine line between safe and unsafe workplaces. Not all individuals react in the same manner to the same amount of a harmful material. The levels of workers’ exposures should be reduced to the lowest practical level achievable. Efforts to reduce workers’ exposures should start at half the exposure limit.

    Want to learn more about chemical safety? Check out our Chemical safety online course!


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    chemical handling chemical routes of entry chemical safety health and safety

    Bruce Levitt | President
    Levitt-Safety Limited Oakville


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