Carbon Monoxide Poisoning: The Cold-Weather Killer!
What is carbon monoxide?
Carbon monoxide is frequently referred to as the "Silent Killer". CO is colorless, odorless, tasteless, and very deadly. Because it cannot be detected by human senses, it can kill you without warning. According to the Journal of the American Medical Association (JAMA) at least 1,500 persons are killed, and at least 10,000 more are forced to seek medical attention every year due to CO exposure.
CO is produced by incomplete combustion, and is frequently associated with the exhaust of internal combustion engines and heating systems. Faulty or poorly maintained furnaces and heaters are a leading cause of indoor CO. Other sources include cigarette smoke, automobile exhaust, wood stoves and fireplaces, dirty or plugged chimneys and many gas, oil, or kerosene powered appliances or machinery.
Inadequate ventilation is a major contributor to CO buildup, especially in winter! Residences and buildings are tightly sealed against the cold, and heaters and furnaces are in constant operation. Often, additional fresh air is all that is required to dissipate low-level CO buildup. Unfortunately, without a carbon monoxide monitor, you'll never know when there is a problem.
Why is carbon monoxide so dangerous?
It's the hemoglobin molecules in our red blood cells that form the bonds which allow red blood cells to transport oxygen. Unfortunately, hemoglobin is also able to form bonds with carbon monoxide. In fact, the bonds that are formed between hemoglobin and carbon monoxide are over 200 times stronger than the bonds that are formed between hemoglobin and oxygen. Red blood cells which have been contaminated with carbon monoxide can't transport O2. In effect, you suffocate "from the inside out".
Because these bonds are so strong they take a long time to break down. The carbon monoxide molecules tend to remain attached, and even low concentrations of CO in the air can lead, over a period of time, to dangerously high concentrations in the blood. That's what makes chronic exposure at even low levels so harmful.
Symptoms of carbon monoxide poisoning
The symptoms of CO poisoning mimic those of many other conditions. They include headaches, fatigue, nausea and other "flu-like" symptoms, as well as (with higher exposure levels) loss of consciousness, coma, and death. A concentration of only a few thousand parts-per-million can be quickly fatal. CO can also exacerbate or worsen pre-existing medical conditions such as heart disease.
How much is too much?
Exposure limits for most industrial workers are regulated by Federal or State Occupational Safety and Health Administration (OSHA) "Permissible Exposure Limits". Current (1996) Federal OSHA rules specify a maximum of 50 ppm , while many states specify a more conservative two part "PEL" which consists of an 8-hr. TWA of 35 ppm, with a maximum exposure limit of 200 ppm.
Residential exposure guidelines are not quite as clear. Home CO detectors listed by Underwriters Laboratories as compliant with Standard 2034, are designed to alarm within 15 minutes at 400 ppm, within 35 minutes at 200 ppm, within 90 minutes at 100 ppm, and within 8 hours at 15 ppm.
Selecting a CO monitor
Gas detectors used to diagnose CO exposure problems should be durable, easy-to-use, provide accurate numerical readings, and respond quickly to changes in CO concentration. The instrument should also use substance-specific, electrochemical sensors for the direct measurement of CO. Finally, it had better be easy to quickly verify the accuracy of the detector, typically accomplished through automatic calibration adjustment.
Reprinted with permission from Biosystems Inc.;exerpted from article by Deputy Chief Wayne Bartolotta, South Fire District, Middletown, CT.
