Minimal Risk Level (MRL)
An estimate of daily human exposure to a hazardous substance that is likely to be without an appreciable risk of adverse noncancer health effects over a specified route and duration of exposure.

Asbestos
A general term applied to certain polysilicate fibrous minerals displaying similar physical characteristics although differing in composition. The most common asbestos mineral (over 95% of U.S. production) is chrysotile, a variety of serpentine, a metamorphic mineral.

ACTS
Asbestos Contractor Tracking System - Asbestos Demolition/ Renovation, and Asbestos Contractor Tracking System in some states is an EPA system

Malignant pleural mesothelioma
Malignant pleural mesothelioma is a type of cancer that affects the inside lining of the chest cavity. It is usually associated with asbestos exposure.

Fibrosis
A condition marked by the increase of connective, fibrous tissue.

Cancer Effect Level (CEL)
The lowest dose of chemical in a study, or group of studies, that produces significant increases in the incidence of cancer (or tumors) between the exposed population and its appropriate control.

RACM
Regulated Asbestos-Containing Material is (a) friable asbestos material, (b) Category I non-friable ACM that has become friable, (c) Category I non-friable ACM that will be or has been subjected to sanding, grinding, cutting or abrading, or (d) Category II non-friable ACM that has a high probability of becoming or has become crumbled, pulverized, or reduced to powder by the forces expected to act on the material in the course of demolition or renovation operations.

Mesothelioma
A rare malignant tumor of the lung membrane which lines the chest and abdominal cavity. Malignant mesothelioma is a cancerous tumor of the pleura (lining of the lung and chest cavity) or peritoneum (lining of the abdomen) that is almost always caused by sustained exposure to asbestos.

Asbestos Containing Material (ACM).
Any material or product that contains more than one percent asbestos.

Excursion Limit (EL)
1 Fiber per cubic centimeter averaged over a 30 minute sampling period.