Coal Workers' X-Ray Surveillance Program (CWXSP)
CWXSP is a NIOSH-administered occupational health program mandated by the U.S. Federal Coal Mine Health and Safety Act of 1969. The primary objective of the CWXSP is to screen miners for coal workers’ pneumoconiosis (CWP). Since 1970, all active underground coal miners have been required to have a chest radiograph at the time of hire and again 3 years later. Subsequently, miners can volunteer for radiographs at approximately 5-year intervals. The chest X-rays are taken at no cost to the miner. In addition, other information is collected, including the miner’s identification, age, tenure, and specific job in the mine.
The chest films are read by physicians certified by NIOSH as proficient in the use of the International Labour Office (ILO) classification system for radiographs of pneumoconiosis [ILO 1980]. Each film is read by at least two Readers (one of whom must be a B Reader*), and a consensus rule is used to reach a final determination for each film. The CWXSP defines CWP as a small opacity profusion category of at least 1/0 or large opacities (i.e., larger than 1 cm in diameter) consistent with pneumoconiosis. Miners with radiographic evidence of CWP on their chest radiographs are offered the option to work in an area of the mine with a respirable coal dust concentration of 1 mg/m3 or less and have personal dust exposures monitored at frequent intervals.
The large number of chest X-rays collected since 1970 provide a means of monitoring the prevalence of CWP among active underground coal miners. However, coal miner participation rates have generally decreased since 1970 to less than 30% of working underground coal miners. Thus, tenure-specific prevalence estimates may be biased because of selective participation. Also, overall crude prevalence estimates may reflect over-representation of newly employed miners. Inferences regarding the entire coal mine work force that are based on CWXSP data should be used with caution. Tabulations of CWXSP data presented in this report may vary from those presented in related NIOSH surveillance reports because of criteria for categorizing tenure and rounding.
For further information, contact
Coal Workers’ X-Ray Surveillance Program Activity
Division of Respiratory Disease Studies
National Institute for Occupational Safety and Health
1095 Willowdale Road, MS–HG900
Morgantown, WV 26505–2888
Telephone: 304–285–5724
www.cdc.gov/niosh/docs/2002-122/
*See Reader in Glossary.
