At any given time, in most any workplace, at least a few people have a cough or itchy eyes. Maybe it's a headache or breathing trouble.

They're allergic to work, right? No, but close. Something about the place where they work—be it car exhaust leaking in from a window, bacteria from mold or chemicals from the carpet—could be making them ill or causing irritation that goes away shortly after they leave work.

The phenomenon is known as sick building syndrome. Symptoms include headache, itchy skin or eyes, dry cough, dizziness, nausea, chest tightness and fatigue.

"I would suggest it [affects] probably 30 percent of the buildings built since the 1960s," says Jack Rostron, a lawyer and professor at John Moores University's School of the Built Environment in Liverpool, England. The World Health Organization has provided a similar estimate.

In the United States, the problem came to light in the 1970s, when industry began sealing buildings tighter for energy efficiency, says Mark Mendell, an epidemiologist with Lawrence Berkeley National Laboratory. Research into workers' complaints of illness didn't point to any one cause, leading some observers to suspect the symptoms were psychosomatic.

The "usual suspects" were studied, such as light, noise, vibration and chemicals. But it was hard to draw any broad conclusions from one building or work force to the next, Mendell says.

Since then, SBS has been substantiated, though the possible culprits are many and solutions are often just best guesses, say Rostron and Mendell. Science hasn't nailed down all the causes of SBS, or how frequently a given cause, such as mold, makes people sick. One building could have a mixture of problems or different problems from one area to the next, causing a range of symptoms. Potential problems will vary based on a building's age, location (industrial area, humid climate), industry and how well its heating, ventilating and air conditioning systems are maintained.

J. David Odom, an indoor air quality expert who specializes in moisture and mold-related problems, says mold is a big troublemaker. "It appears to me, and I believe many others, that mold is by far the most common indoor air complaint of building owners," he says.

Common symptoms of mold problems include eye, nose and respiratory irritation, he says. And while you can sometimes see or smell mold, often it's hard to locate, he says.

Odom notes that grocers have a few extra reasons to carefully monitor moisture levels in their buildings. Refrigeration equipment and water sprays in the produce department may increase humidity levels and lead to condensation problems.

Chemical sources include glues, upholstery, carpet, cleaning agents, copy machines and composite wood products that emit volatile organic compounds, including formaldehyde. Motor vehicle exhaust and other fumes can enter the building from outside.

Biological sources of SBS include bacteria, viruses and molds. One indoor bacteria known to grow in standing water can lead to Legionnaires' disease, a type of pneumonia.

No matter the cause of SBS in a particular building, its occupants typically get sick by inhaling something. But identifying a cause of SBS is also hard because workers who complain of symptoms don't operate in a vacuum. Two people in the same department may say they get headaches only at work. One might be sensitive to chemical fumes in the carpet, while the other gets head-aches from job stress.

With so many variables, some building owners simply ignore the problem, Mendell says. And though it's difficult to prove in court that a building made you sick, a few workers have won personal injury settlements based on SBS.

(While SBS refers chiefly to symptoms that disappear upon leaving work, buildings also can be the source of longer-term health problems, referred to as "building-related illnesses." In this instance, the symptoms?including cough, fever, chills and muscle aches—can be clinically defined and, unlike SBS, the cause of the illness is clear, according to the U.S. Environmental Protection Agency. Radon and asbestos are not included in SBS because they are known to cause serious illness).

Scientists and private firms agree on several ways building owners can avoid or mitigate problems that could cause building-related symptoms.

Because scientists don't know the totality of what causes SBS, much of the current research focuses on what they believe to be one of the biggest culprits—mold.

"There are lots of studies that show dampness or visible mold in buildings can be related to asthma," Mendell says, "but nobody knows what exactly in there is causing the problem—fungi, microbials, dust mites."

For more help go to www.epa.gov/iaq/iaqinfo.html, or contact private firms that test air quality and provide remediation services.

Kelly Pate Dwyer is a freelance writer in Denver.

Natural Foods Merchandiser volume XXVII/number 4/p. 14, 16