Park Meadows Blog

Beware the Dangers of Carbon Monoxide

Carbon monoxide poisoning occurs after the inhalation of carbon monoxide gas. Carbon monoxide (CO) is a product of combustion of organic matter under conditions of restricted oxygen supply, which prevents complete oxidation to carbon dioxide. Carbon monoxide is colorless, odorless, tasteless, and non-irritating, making it difficult for people to detect.

Common sources of CO which may lead to poisoning include house fires, furnaces/heaters, wood-burning stoves, motor vehicle exhausts, and propane-fuelled equipment such as portable camping stoves, ice resurfacers, forklifts, engine-driven generators, and confined spaces.

Carbon monoxide poisoning is the most common type of fatal poisoning in the United States and France. It has been estimated that more than 40,000 people per year seek medical attention for carbon monoxide poisoning in the United States. In many industrialized countries carbon monoxide may be the cause of greater than 50% of fatal poisonings. In the U.S., about 200 people die each year from carbon monoxide poisoning associated with home fuel-burning heating equipment.

Symptoms

The earliest symptoms, especially from low level exposures, are often non-specific and readily confused with other illnesses, typically flu-like viral syndromes, depression, chronic fatigue syndrome, and migraine or other headaches. Often this makes the diagnosis of carbon monoxide poisoning difficult. If suspected the diagnosis can be confirmed by measurement of blood carboxyhemoglobin.

The main manifestations of poisoning develop in the organ systems most dependent on oxygen use: the central nervous system and the heart. The clinical manifestations include tachycardia and hypertension, and central nervous system symptoms such as headache, dizziness, confusion, convulsions, and unconsciousness. CO poisoning may also produce myocardial ischemia, atrial fibrillation, pneumonia, pulmonary edema, hyperglycemia, muscle necrosis, acute renal failure, skin lesions, visual and auditory problems, and respiratory arrest.

Long term, repeat exposures present a greater risk to persons with coronary heart disease and in pregnant patients. Chronic exposure may increase the incidence of cardiovascular symptoms in some workers i.e. motor vehicle examiners, firefighters, and welders. Patients often complain of persistent headaches, lightheadedness, depression, confusion, and nausea. Upon removal from exposure the symptoms usually resolve.

Toxicity

Carbon monoxide is a significantly toxic gas, although patients may demonstrate varied clinical manifestations with different outcomes, even under similar exposure conditions. Toxicity is also increased by several factors including: increased activity and rate of ventilation, pre-existing cerebral or cardiovascular disease, reduced cardiac output, anemia or other hematological disorders, decreased barometric pressure, and high metabolic rate.

Under ordinary conditions, it is less dense than air, but during fires, it accumulates on the ground, so that if poisoning causes loss of consciousness, the amount of carbon monoxide inhaled increases and so fatality is radically increased.

Carbon monoxide is life-threatening to humans and other forms of air-breathing life, as inhaling even relatively small amounts of it can lead to hypoxic injury, neurological damage, and possibly death. A concentration of as little as 0.04% (400 parts per million) carbon monoxide in the air can be fatal. The gas is especially dangerous because it is not easily detected by human senses. Early symptoms of carbon monoxide poisoning include drowsiness and headache, followed by unconsciousness, respiratory failure, and death. First aid for a victim of carbon monoxide poisoning requires access to fresh air; administration of artificial respiration and, if available, oxygen; and, as soon as possible, medical attention.

When carbon monoxide is inhaled, it takes the place of oxygen in haemoglobin, the red blood pigment that normally carries oxygen to all parts of the body. Because carbon monoxide binds to haemoglobin several hundred times more strongly than oxygen, its effects are cumulative and long-lasting, causing oxygen starvation throughout the body. Prolonged exposure to fresh air (or pure oxygen) is required for the CO-tainted hemoglobin (carboxyhaemoglobin) to clear. Carbon monoxide detectors for homes are now readily available and are increasingly being required by municipal building codes.

The effects of carbon monoxide in parts per million are listed below:

• 35 ppm (0.0035%) Headache and dizziness within six to eight hours of constant exposure
• 100 ppm (0.01%) Slight headache in two to three hours
• 200 ppm (0.02%) Slight headache within two to three hours
• 400 ppm (0.04%) Frontal headache within one to two hours
• 800 ppm (0.08%) Dizziness, nausea, and convulsions within 45 minutes. Insensible within two hours.
• 1,600 ppm (0.16%) Headache, dizziness, and nausea within 20 minutes. Death in less than two hours.
• 3,200 ppm (0.32%) Headache, dizziness and nausea in five to ten minutes. Death within 30 minutes.
• 6,400 ppm (0.64%) Headache and dizziness in one to two minutes. Death in less than 20 minutes.
• 12,800 ppm (1.28%) Death in less than three minutes.

In addition, a recent report concludes that carbon monoxide exposure can lead to significant loss of lifespan after exposure due to damage to the heart muscle.

Treatment

First aid for carbon monoxide poisoning is to immediately remove the victim from the exposure without endangering oneself, call for help, and applying CPR if needed. The main medical treatment for carbon monoxide poisoning is 100% oxygen by a tight fitting oxygen mask. Oxygen hastens the dissociation of carbon monoxide from hemoglobin, improving tissue oxygenation by reducing its biological half-life. Hyperbaric oxygen is also used in the treatment of CO poisoning; hyperbaric oxygen also increases carboxyhemoglobin dissociation and does so to a greater extent than normal oxygen. Hyperbaric oxygen may also facilitate the dissociation of CO from cytochrome oxidase.

Prevention

Prevention remains a vital public health issue, requiring public education on the safe operation of appliances, heaters, fireplaces, and internal-combustion engines, as well as increased emphasis on the installation of carbon monoxide detectors. Carbon monoxide alarms are usually installed in homes around heaters and other equipment. If a high level of CO is detected, the device sounds an alarm, giving people in the area a chance to ventilate the area or safely leave the building. Unlike smoke detectors, they do not need to be placed near ceiling level. The Consumer Product Safety Commission says that "carbon monoxide detectors are as important to home safety as smoke detectors are", and recommends that each home should have at least one carbon monoxide detector.

The devices, which retail for $20-$60USD and are widely available, can either be battery-operated or AC powered (with or without a battery backup). Since CO is colorless and odorless (unlike smoke from a fire), detection in a home environment is impossible without such a warning device. Some state and municipal governments, including Ontario, Canada and New York City require installation of CO detectors in new units. Massachusetts and Illinois began to require a detector in all residences on January 1, 2007.

Professionals can test for the presence of CO leaks in customers’ homes by bringing a carbon monoxide leak detector with them to each job. In industrial environments, workers can protect themselves from the dangers of CO poisoning in several ways. Portable gas monitors can be worn that alert to the presence of dangerous levels of CO. When a worker must knowingly enter an area where CO or other harmful gases are present, he or she must wear personal protective equipment, including respirators and protective clothing.