Hemoglobin readily accepts carbon monoxide over the life-giving oxygen atoms – as much as 200 times as readily as oxygen – forming a toxic compound known as carboxyhemoglobin.

Low levels of carbon monoxide poisoning result in symptoms commonly mistaken for common flu and cold symptoms: shortness of breath on mild exertion, mild headaches and nausea.

With higher levels of poisoning, the symptoms become more severe: dizziness, mental confusion, severe headaches, nausea and/or fainting upon mild exertion. At high levels there may be unconsciousness and death.

Compounding the effects of the exposure is the long half-life of carboxyhemoglobin in the blood. Half-life is a measure of how quickly levels return to normal. The half-life of carboxyhemoglobin is about five hours. This means that for a given exposure level, it will take about five hours for the level of carboxyhemoglobin in the blood to drop to half its current level after the exposure is terminated.

So, the real question becomes how much is too much? Symptoms vary widely based on exposure level, duration, and the general health and age of an individual. The one recurrent theme that is most significant in the recognition of carbon monoxide poisoning is headache, dizziness and nausea.

These “flu-like” symptoms are often mistaken for a real case of the flu and can result in delayed or misdiagnosed treatment. The chart on this page shows exposure limits.

The OSHA standard for exposure to carbon monoxide prohibits worker exposure to more than 35 PPM of CO, averaged over an eight-hour workday. There is also a ceiling limit of 200 PPM, as measured over a 15-minute period.

Work safe, work smart and CYA.

Dave Yates owns F.W. Behler, a contracting company in York, Pa. He can be reached by phone at 717/843-4920 or by e-mail at .