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Carbon monoxide (CO) is a colorless, odorless, and tasteless gas and one of the most common industrial hazards. CO results from the incomplete burning of natural gas and any other material containing carbon, such as gasoline, kerosene, oil, propane, coal, or wood. Forges, blast furnaces, and coke ovens produce CO, but CO exposure in the workplace most often results from the internal combustion engine.
Scope
Harmful levels of CO are a potential danger to anyone who works around equipment that uses internal combustion. Employees most at risk include those who work in boiler rooms, breweries, warehouses, petroleum refineries, pulp and paper production, and steel production; around docks, blast furnaces, or coke ovens; or those who work in or around:
- Acetylene
- Carbon black
- Customs
- Diesel engines
- Garages
- Metal oxide reducing
- Mines
- Organic chemical synthesizers
- Toll booths and tunnels
CO poisoning occurs when the gas is breathed in. CO replaces oxygen in the blood, which deprives the body of oxygen, resulting in flu-like symptoms ranging from headache, dizziness, flushed skin, disorientation, troubled thinking, abnormal reflexes, shortness of breath, fainting, and convulsions. CO poisoning can even lead to coma and death.
CO poisoning can be reversed it caught in time. However, even when someone recovers, exposure to CO may result in permanent damage to critical parts of the body such as the heart and brain.
Employee exposure to CO is of particular concern in confined spaces.
The OSHA Permissible exposure limit for CO is 50 parts per million (ppm). OSHA standards prohibit worker exposure to more than 50 parts of the gas per million parts of air averaged during an 8-hour time period.
Regulatory citations
- 29 CFR 1910.1000 — Air contaminants
Key definitions
- 8-hour time-weighted average (TWA): The employee’s average airborne exposure in any 8-hour work shift of a 40-hour work week.
- Carbon monoxide (CO): A poisonous gas.
- Internal combustion engine: An engine that is powered by burning fuel mixed with air inside it. The hot gases produced drive a piston or do other work.
- Permissible exposure limit (PEL): The highest level of exposure to a chemical or physical hazard that an employee may be exposed to without incurring the risk of adverse health effects. PELs are usually expressed in an 8-hour time-weighted average.
Summary of requirements
To reduce the chances of CO poisoning in the workplace, employers should take the following actions:
- Install an effective ventilation system to remove CO from work areas;
- Maintain equipment and appliances (e.g., water heaters, space heaters) that can produce CO in good working order to promote their safe operation and to reduce CO formation;
- When feasible, switch from oil- and gas-powered equipment to equipment that uses electricity, batteries, or compressed air;
- Prohibit the use of internal combustion engines or tools in poorly ventilated areas;
- Provide personal CO monitors with audible alarms if there is the potential of exposure to CO;
- Test air often in areas where CO may be present, including confined spaces.
- Do not allow employees to enter confined spaces where CO is suspected without first testing for oxygen sufficiency;
- Install area CO monitors with audible alarms;
- Use correct respirators when necessary;
- Train workers to recognize conditions where CO may form, signs and symptoms of CO poisoning, and what to do if they suspect CO poisoning.
To reduce the chances of CO poisoning, employees should take the following actions:
- Report any situation that might cause CO to accumulate;
- Pay attention to the ventilation system and report any problems;
- Suspect CO as a cause for complaints of dizziness, drowsiness, or nausea;
- Promptly leave the area if you suspect CO contamination;
- Seek medical treatment for suspected CO poisoning;
- Do not use gas-powered engines while working in enclosed spaces.