A valve is a mechanical structure used to control the flow of a gas or fluid by opening, closing, or partially regulating its flow through various passageways. They are commonly found in equipment related to plumbing and heating systems such as boilers and turbines. Valves are also a common component in stems packing and rings in many Navy ships and vessels including aircraft carriers, destroyers and submarines.  Due their exposure to high temperatures, these valves need to be insulated and asbestos used to be the preferred material for this purpose.

The key factors in the exposure equation to asbestos are the duration and quantity of asbestos fibers present in the suspected materials. Asbestos is found in most building materials and other equipment in manufacturing industries including but not limited to turbines, pipes and valves. The longer and more intense the exposure to asbestos, the more likely it is to be toxic, though even brief exposure can sometimes prove to be fatal.

Prolonged exposure to asbestos by workers who dealt with valves in pipe fitting, steam fitting, boiler making and plumbing on the job made them susceptible to developing diseases such as cancer and lung conditions after inhaling substantial amount of fiber without their knowledge. Sailors whose primary job was to install, maintain and repair valves that were crucial to the functioning of the ship are also prone to develop mesothelioma, lung cancer, and asbestosis.

The EPA has established clearance levels for various asbestos-removal projects. Although many standards currently exist for asbestos abatement, air monitoring is the common procedure to evaluate levels before and after abatement. Also, plenty of information is available for people who have worked with valves, valve rings, valve stem packing or similar products, and who have been diagnosed with mesothelioma or other asbestos-related disease.