Mesothelioma Definitions

The following are terms and definitions commonly associated with asbestos and mesothelioma, the cancer associated with asbestos exposure.

Abatement - Procedures designed to control the release of friable asbestos from ACM.

Asbestos - this naturally occurring mineral is broken into two groups: serpentine and amphibole.  There are several types of amphibole asbestos (tremolite, anthophyllite, corcidolite, etc. etc.).  The serpentine group only has one type of asbestos, chrysotile.  This mineral is typically used to increase the tensile strength of concrete sheeting and as insulation for pipes, boilers, engines, and automobile breaks. 

Asbestosis - A chronic, progressive lung disease cause by a scarring of the tissue of the lung itself from inhalation of asbestos particles. See also mesothelioma.

Asbestos Containing Material (ACM) - any material that contains more than one percent of asbestos.  This includes goods like insulation, roofing tiles, fire proofing, and gaskets.

Asbestos Project - typically an abatement project focused on safely encapsulating or removing friable ACMs from buildings or demolishing a building with asbestos inside.

Disturb - disturbances refer to activities that alter the physical matrix of the asbestos, releasing friable asbestos into the air.  Basically, any activity that would cause asbestos to crumble or pulverize, releasing asbestos particles thereby contaminating the air.

Friable Asbestos - any ACM that contains more than 1% asbestos and that, when dry, is susceptible to crumbling or being reduced to powder by hand pressure. 

Intact Asbestos - any ACM that has not been disturbed or cannot be crumbled or otherwise deteriorated to the point that the asbestos is no longer bound to its matrix (i.e. asbestos mixed into concrete).

Leak Tight - refers to asbestos encasings or protective clothing that does not allow water or dust to escape. 

Mesothelioma - A rare type of cancer typically linked to asbestos exposure that affects the pleura membrane surrounding the lungs or the lining of the abdomen.

Occupational Health and Safety Administration (OSHA) - This division of the Department of Labor is responsible for regulating standards and practices for installing, removing, or handling ACMs; as well as procedures for monitoring and reporting asbestos contamination and exposure.  OSHA breaks down asbestos-related work into four classes, with Class I being the most dangerous and Class IV the least dangerous. 

Permissible Exposure Level (PEL) - the OSHA limit for personal exposure to any dangerous substance, in this case asbestos.  The 8-hour PEL for asbestos is .1 fibers per cubic centimeter.

Potential (or Presumed) Asbestos Containing Material (PACM) - any thermal system insulation or surfacing materials installed prior to 1980 which are assumed to contain greater than 1% asbestos.

Thermal System Insulation - insulation applied to pipes, boilers, tanks, etc. to prevent heat loss or gain.