Carbon Monoxide – The Silent Killer

Welcome back, let’s Build Smart & Build Safe! Many companies treat temporary heating as a standard convenience without accounting for the primary byproduct of combustion: Carbon Monoxide (CO). CO is a colorless, odorless, and tasteless gas that displaces oxygen in the bloodstream. In the enclosed environments of winter construction, CO accumulation can reach lethal levels in minutes.

The Mechanism of Poisoning

CO binds to hemoglobin in the blood with significantly higher affinity than oxygen. This creates carboxyhemoglobin, which prevents the blood from transporting oxygen to the brain and heart. Because the gas is undetectable by human senses, workers often do not realize they are being poisoned until they are physically incapacitated.

Mandatory Ventilation and Monitoring

Under OSHA 1926.154, temporary heaters must be provided with sufficient fresh air to maintain a safe atmosphere. Relying on "incidental" leaks in a building envelope is an unacceptable safety practice.

• Ventilation: A minimum of one square inch of vent area for every 1,000 BTU of heater output is a general engineering guideline for fresh air intake. If air movement is not perceptible, ventilation is likely insufficient.

• Atmospheric Monitoring: The use of portable CO monitors with audible and visual alarms is the only reliable way to ensure a safe environment. These should be placed in the breathing zone of the workers, not just next to the heater.

• Burner Integrity: A clean-burning propane or kerosene heater should have a steady blue flame. A yellow or flickering flame indicates incomplete combustion and elevated CO production.

Recognition of Symptoms

CO symptoms are frequently mistaken for the flu or general fatigue, which often leads to workers remaining in the hazardous area.

Action: If a CO alarm sounds or a worker exhibits symptoms, evacuate the area immediately to fresh air. Do not re-enter the space until it has been cleared by atmospheric testing.

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-The Safety Man