Under construction: building a safer industry

Environmental Health Perspectives, March, 2002 by John Tibbetts

Construction is a risky occupation--on a daily basis, construction workers face environmental exposures to many dangerous materials and practices. Drillers, sandblasters, drywall sanders, and brick masons risk inhaling particles of dust, sand, and crystalline silica, which can lead to lung cancers, tuberculosis, and silicosis. Welders and other metalworkers risk inhaling metal fumes, which can cause lung ailments, airway disorders, and cancer. Asphalt used in paving and roofing has been linked to throat irritation, nausea, and chronic lower respiratory infections. Workers doing finishing work can breathe in toxic fumes from paints, adhesives, floor finishes, and other materials. And renovation and demolition of old buildings exposes workers to lead paint, asbestos, and toxic molds.

Over the past decade, however, the building industry has been taking aim at environmental hazards for workers. The results have spawned a new generation of safer materials and better safety training and practices to decrease risks and safeguard worker health.

Along with changes within the industry, outside forces are also helping to shape the landscape. For instance, a growing number of consumers are demanding that builders and developers use environmentally friendlier and safer materials. Architects are increasingly taking into account the human health impacts of building materials. Numerous government agencies have specified the purchase of "green" building materials, thus encouraging an expanding market for these products. Regulatory agencies, manufacturers, and nonprofit organizations have established standards and guidelines for hazardous emissions from building materials. And efforts to improve worker education in environmental health are increasing. The result is that many construction workers are handling fewer toxic materials, and homeowners and office workers are better able to live and work in healthier environments.

Hard Hat Areas

It can be difficult to tease out the effects of specific building materials and practices on human health because of possible confounding factors such as multiple toxic exposures, worker lifestyle factors, previous illnesses, and chemical sensitivities that can exacerbate tendencies toward occupational illness. Respiratory diseases can occur due to interactions among workplace hazard exposures and other factors such as nutrition, exposure to chemicals through hobbies, cigarette smoking, and illnesses such as gastroesophageal reflux disease and viral infections. Workers who smoke, for example, have a 10 times higher risk of developing lung cancer from asbestos exposure than workers who do not smoke, according to Asbestos in Construction, a hazard alert published by The Center to Protect Workers' Rights, a research and education program of the AFL-CIO based in Silver Spring, Maryland.

Unusual sensitivities to chemical or hazardous materials also contribute to occupational illnesses. Some researchers argue that a long-term, low-level exposure to a hazardous substance, or a large one-time dose, can turn the biological switch that activates chemical sensitivity. "When you look at the range of the human population, there may be up to a tenfold difference in chemical sensitivity," says Kaye H. Kilburn, a physician specializing in environmental medicine and occupational health at the University of Southern California Keck School of Medicine in Los Angeles. "A one hundredfold or one thousandfold or ten thousandfold increase in chemical sensitivity from the normal range says that something has happened to make this person hypersensitive. There are hundreds of people running around with chemical sensitivity who were perfectly normal before an indoor air exposure or exposure to a dose of chemical," she says.

Still, there are many known effects from specific exposures that the construction labor force, homeowners, and residents near construction sites face. And it is in reducing these effects in particular that efforts are being directed.

Volatile organic compounds (VOCs). VOCs are organic chemicals that become a breathable vapor or gas at room temperature. VOCs such as formaldehyde, benzene, ethylene glycol, and vinyl chloride are commonly used in building materials including solvents, binding agents, and cleaning agents. Managing VOCs remains one of the most important considerations in controlling indoor air pollution and health effects for installers and occupants of new construction.

For many years, high-VOC paint was the industry standard. Heavy amounts of VOC solvents were added to paint to enhance color and spreadability, and also to function as fungicides and biocides. But VOCs "off-gas" during the application and curing of paint, and even after the paint is dry. These emissions can cause headaches, respiratory problems, and allergic reactions.

It is difficult to determine the average level of worker exposure and a specific "unsafe" VOC dose for two reasons. First, VOCs in paint can react in the air and with other chemical coatings to create new compounds with health effects that are not fully known. Also, VOCs can be harvested from natural or synthetic sources, and the health effects can vary widely, depending on the VOC source.