by Safety Management Group
When NASCAR driver Rick Mast called it quits back in 2002, safety was the primary factor. It wasn’t that the veteran driver had developed a fear of accidents or worried about debris on the track. Something inside his race car had been making him very sick.
As he’d exit his car after races, Mast felt miserable, comparing his symptoms to having “the worst hangover of your life.” When his doctor ran toxicology tests on his blood, he discovered that the driver was suffering from chronic carbon monoxide poisoning. Other drivers -- among them Tony Stewart and Richard Petty -- reported similar problems after races.
Amazing as it seems, the ventilation of an open-window car traveling at close to 200 mph wasn’t enough to protect these drivers’ bloodstreams from accumulating this deadly poison. So it should come as no surprise that workers on construction sites are often surprised by the insidious danger lurking in combustion emissions.
Although it’s a year-round concern, colder weather means that more workers will be bringing equipment indoors and trying to block outdoor air in an effort to stay warmer. But even small pieces of equipment that seem harmless can produce surprising amounts of carbon monoxide in a very short period of time.
Carbon monoxide is an asphyxiant that’s colorless and odorless, so it’s impossible to detect without special equipment. It has the same density as air, so it mixes freely. As you breathe it, it binds with the hemoglobin in your bloodstream and displaces the oxygen that’s normally there. Unlike other chemical irritants such as ammonia, you can breathe carbon monoxide until you develop acute symptoms, and you probably won’t even realize it.
The most common symptoms are headaches and nausea, which are also associated with all manner of illnesses and are often a way of life on construction sites. Other symptoms include weakness, personality changes, a bright red glow on skin, visual problems, and dizziness. Even when carbon monoxide doesn’t kill someone, it can leave the individual with permanent neurological damage.
Everyone agrees that carbon monoxide is dangerous, but the organizations that set safety standards can’t seem to reach agreement on just how much exposure poses a risk. For example, OSHA sets a permissible exposure limit of 50 parts per million averaged over eight hours. The National Institute for Occupational Safety and Health (NIOSH) has a recommended exposure limit of 35 ppm over the same time period, and the American Conference of Governmental Industrial Hygienists calls for an average of 25 ppm.
But most workers on construction sites don’t have ready access to monitoring equipment. For them, the key is to be aware of the hazard, and to find ways to minimize it. The first step is to take it seriously. Many workers think nothing of using something like a small gas-powered pressure washer indoors without giving the exhaust a second thought. As winter gets colder, construction workers will often move tasks to enclosed spaces and use kerosene-fueled torpedo heaters to improve their comfort.
An alert issued by NIOSH included several stories of workers unexpectedly being overcome by surprisingly small equipment. One farmer who was cleaning his barn with an 11-horsepower, gasoline-powered pressure washer died after just 30 minutes of exposure. Another worker at a water treatment plant collapsed while working with an 8-horsepower, gasoline-powered pump. In both cases, the equipment was small and there was plenty of room for air to circulate. Often, workers will believe than an open door, a couple windows, or a fan will provide enough ventilation to protect them. Others think a dust mask or organic respirator will block carbon monoxide, but that’s not the case. You either need a supply of oxygen or sufficient ventilation.
The safest approach to preventing carbon monoxide poisoning is to engineer the hazard out of the jobsite. First, ask yourself if you really need to use the particular piece of equipment in that location, or if something without combustion can handle the job. If you still need to use it, you may be able to place the device away from the work area. For example, you can leave a generator outside and use an extension cord to bring the power to the task. Or, if you’re using a pressure washer, a longer hose will let you accomplish the task without having to be in close proximity to the motor.
Reading the operating manual -- particular if it’s a rented or otherwise unfamiliar piece of equipment -- will give you the manufacturer’s recommendations for ventilation and safe operation. And don’t assume that a piece of equipment you’ve used before without problems is inherently safe. Many poisonings involve familiar equipment in familiar surroundings, where workers have been misled by a false sense of security.
Proper maintenance and fuel choices can also minimize the hazards associated with carbon monoxide. Always inspect the equipment before use, so you can see if there’s a cracked manifold or anything else that might increase the amount of emissions. In addition, match the fuel to the specifications. Some kerosene-powered heaters specify a particular type of kerosene that has low sulfur content. Substituting another grade or type of fuel could increase the levels of dangerous emissions.
What do you do if you suspect that you or someone at your workplace is experiencing carbon monoxide poisoning? First, shut off the equipment that’s being used, and move the worker outside or any place with clear air. Then obtain prompt medical attention. Never let someone who is exhibiting symptoms drive to the emergency room or clinic, because their judgment and motor skills may be affected. Finally, don’t allow anyone into the area or to use the equipment until the problem has been investigated and the air is safe once again.