The Agency for Toxic Substances and Disease Registry (ATSDR), a public health agency of the U.S. Department of Health and Human Services, today releases major findings of its 2000 asbestos medical testing program in Libby, Montana.

From July 5 through November 2, 2000, 6,149 people participated in the testing program. Those eligible for testing included former W.R. Grace Company workers from Libby and others who lived, worked, or played in Libby for at least 6 months prior to December 31, 1990.

• a face-to-face interview designed to obtain information needed to better analyze the health information. Questions asked included years living in the Libby area, smoking history, and exposure variables (such as having been a W.R. Grace worker, playing in vermiculite piles, playing at the ball field near the expansion plant, etc.)

• a three-view chest x-ray to identify changes in the lungs and lung lining that might be the result of asbestos exposure.

• a spirometry test that measured air flow in and out of the lungs to see how the lungs were functioning.

X-Ray Findings

Only study participants 18 years of age and older were eligible for x-ray testing. Three B-readers (experts in reading chest radiographs for lung abnormalities) found that 994 of those 5,590 participants (or 18% of those x-rayed) had abnormalities in the lining of their lungs (pleural abnormalities). The risk of pleural abnormalities increased with increasing age and increasing length of residence in the Libby area. The rate of pleural abnormalities found in groups within the United States who have no known asbestos exposures ranges from 0.2% to 2.3%.

Additional Findings

• Forty-eight percent (159 of 328) of former W.R. Grace employees had pleural abnormalities.

• Most participants reported multiple routes of exposure (household contact, occupational, recreational, and other). For example, 24% of participants who reported six or more routes of exposure had pleural abnormalities.

• Five percent (6 of 122) of those participants who reported no apparent exposure had pleural abnormalities.

Factors most strongly related to having pleural abnormalities were having been a W.R. Grace/Zonolite worker, having household contact with a W.R. Grace/Zonolite worker, and being a male.

• The risk of finding a pleural abnormality is almost 8 times greater for former W.R. Grace workers when compared to non-W.R. Grace workers of the same age.

• The risk of finding a pleural abnormality is 3.3 times greater for females who have household contact with W.R. Grace workers when compared to women who have no household contacts with these workers.

• The risk of finding a pleural abnormality is 5 times greater for men than for women.

Lung Function Test Findings

Lung function tests (spirometry) were offered to all study participants. An on-site pulmonologist from the National Jewish Medical Center interpreted all tests. Some of the key findings include the following:

• Being a current smoker was the strongest risk factor for restrictive changes.

• Moderate to severe restriction in breathing capacity was found in 5.7% of former W.R. Grace workers.

• Moderate to severe restriction in breathing capacity was found in 2.2% of men and 1.6% of women (men and women defined as 18 years of age and older).

• In those under 18 years of age who were tested, no one had moderate to severe restricted lung function.

• Other factors affecting restricted breathing included (a) being a non-W.R. Grace/Zonolite worker exposed to vermiculite, (b) having had chest surgery, and (c) being overweight.

Public Health Follow-up

ATSDR, the Environmental Protection Agency, the Public Health Service Region VIII, and other federal agencies are committed to providing support for residents of the Libby community. Recently, funding from the Health Resources Services Administration (HRSA) (a Department of Health and Human Services (DHHS) agency) was obtained to establish a community health clinic in Libby for medically under-served individuals. This clinic will provide primary care services for those individuals with asbestos-related disease.

The Center for Asbestos Related Disease (CARD clinic) at St. Johns' Lutheran Hospital (SJLH) will continue providing follow-up diagnostic evaluations for individuals with potential exposures and those with identified x-ray abnormalities. Psychological and social services, education, and outreach for those affected by asbestos-related issues or conditions will be provided by SJLH under a one-year contract from the Substance Abuse and Mental Health Services Administration (SAMHSA), another DHHS agency.

Copies of the report are available for public review at the following public repositories:

Community members seeking further information on the content of this report or the testing procedures, or who would like to receive a copy, can contact the ATSDR Information Center, toll free, at 1 (888) 42-ATSDR (1-888-422-8737), or the ATSDR office in Libby at (406) 293-2728. Callers should refer to the "Libby, Montana, site." Also, ATSDR Regional Representative Dan Strausbaugh in Helena, Montana, may be called for information at (406) 441-1120, ext. 257.

For more information about asbestos and health effects related to asbestos exposure, please visit the ATSDR Web site at http://www.atsdr.cdc.gov and click on ToxFAQs for Asbestos.