The same material that helped to protect buildings, ships and locomotives from the high heat of boilers has put thousands of boilermakers at risk for serious health problems including mesothelioma.

Boilers are closed vessels in which water or other fluid is heated to produce steam. The steam can be used for various applications such as powering steam locomotives and ships in the past, and heating and providing hot water for buildings today. Because of the high heat generated by boilers, many were installed surrounded by one of the most heat-resistant insulators ever known €" asbestos.

Long before asbestos, a naturally occurring mineral, had been linked to deadly diseases such as lung cancer, asbestosis and mesothelioma, thousands of people who repaired and maintained boilers, known as boilermakers, were exposed to the substance. The fact that boilermakers often worked in cramped quarters with the noxious material on a regular basis compounded their risk.

While asbestos insulation poses little risk when undisturbed, when the outer canvas that typically surrounds and holds it in place is cut, moved or otherwise manipulated, tiny fibers can be released into the air and inhaled. Boilermakers who were exposed to these fibers, either during routine maintenance, repair or removal of a boiler ran a greater risk of breathing in the fibers, which lead to lung irritation, scarring and sometimes mesothelioma. Even family members have been put at risk for mesothelioma from boilermakers who carried the deadly substance home in the form of asbestos dust on their work clothes.

National Cancer Society statistics show that boilermakers, along with shipbuilders, plumbers and electricians, have a much greater incidence of mesothelioma than other professions, because of the likelihood of asbestos exposure. And because mesothelioma can take 30 to 50 years to develop after exposure, even retired boilermakers remain at risk.

The Consumer Product Safety Commission banned the use of asbestos in many construction materials in 1977. But well-made boilers can last for decades and thousands are still in place, wrapped in their deteriorating asbestos insulation. In addition, asbestos was often used in the sealants for the boiler or boiler pipes, in the tape used to prevent leaks, and in the gasket which protects the boiler's inner parts from extreme heat. Manipulation of any of these materials can release microscopic fibers and cause serious harm.

Approximately 2,000 to 3,000 people are diagnosed with mesothelioma every year. About 80 percent of those cases can be directly linked to asbestos exposure on the job.