OHS Canada Magazine

Protect against respiratory hazards with knowledge

March 16, 2019
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By Jean Lian

A multitude of toxic gases may be present depending on the environment. For those who work in confined spaces, ship repair or mining, workers need to be acutely aware of all hazardous materials to which they might be exposed, and that could mean familiarizing themselves with terminologies like Expoure Limits (ELs), Threshold Limit Values (TLVs) and Immediately Dangerous to Life and Health (IDLH).

According to the Canadian Centre for Occupational Health and Safety in Hamilton, Ontario, there are several conditions that are considered “Immediately Dangerous to Life or Health (IDLH)”. They include the following:

• A known contaminant at a concentration known to be IDLH;
• A known contaminant at an unknown concentration with the potential to be IDLH;
• An unknown contaminant at an unknown concentration;
• An untested confined space;
• An oxygen-deficient atmosphere;
• Firefighting; and
• Contaminants at or above 20 per cent of their lower explosive limit or LEL, which refers to the concentration at which the gas or vapour could ignite.

“Being a part of the safety effort includes knowing as much as you can about your work and allows you to ask pertinent questions about the work you are being asked to do,” says Dr. Ken Jenkins, national medical director of Horizon Occupational Health Solutions in St. John’s, Newfoundland.

Some of the best-known toxic workplace gases are carbon monoxide, chlorine and phosgene. Although carbon monoxide is odourless and the odour of phosgene gas — a major industrial chemical used to make plastics and pesticides — may not be detectable at low concentrations, there are warning signs that speak to the presence of these gases:

– Carbon Monoxide, which can be lethal, typically causes headaches, dizziness, breathlessness, nausea, collapse and/or loss of consciousness.

– Chlorine gas causes acute damage in the upper and lower respiratory tract. Its symptoms include difficulty breathing, cough, sneezing, nose and throat irritation, nausea, vomiting and/or a headache.

– Phosgene gas can cause irritation of the lungs and delayed onset failure of the heart and lungs. Symptoms of exposure include coughing, burning sensation in the throat and eyes, watery eyes, blurred vision, shortness of breath and/or nausea and vomiting.

If an individual experiences any of these symptoms, Dr. Jenkins advises getting the exposed worker into fresh air as soon as possible and seeking medical response immediately. If the person vomits, turn his or her head to the side to prevent choking and begin cardiopulmonary resuscitation if the person shows no signs of life. An individual assigned to gather information about the toxic substance should be sent along with the ambulance team.

Understanding one’s personal protective equipment is important. “If you are a new user to respirators, make sure that you completely understand how yours works before you end your training session,” Dr. Jenkins advises. Even experienced users need to exercise due caution. “Make sure you don’t get complacent with maintenance of your respirator — it can be a matter of life or death.”

Jean Lian is editor of OHS Canada.