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Epidemiologic Notes and Reports PCB Contamination of Ceiling Tiles -- Madison, Wisconsin

In November of 1986, a manufacturer of ceiling tiles notified a local public school in Madison, Wisconsin, that the school contained ceiling tiles contaminated with polychlorinated biphenyl (PCB) compounds. The manufacturer offered to replace the tiles, and the Wisconsin Department of Health and Social Services, in cooperation with Madison officials and local representatives of the manufacturer, investigated the potential health hazard. The study included environmental monitoring before and after removal of the contaminated tiles and an analysis of PCB levels in serum samples from the school's staff.

Ceiling tiles manufactured by this company were first identified as a source of PCB contamination of air and surfaces during an investigation of a fire at a community college in New Jersey (1). Following this fire, the company reported that PCB- containing tiles had been manufactured in limited quantities in 1969 and 1970. The Madison, Wisconsin, public school was one of four sites in the United States known to contain these tiles.

Before removal of the tiles, air concentrations of PCB (quantified as an isomeric mixture containing 54% chlorine by weight) in the Madison school ranged from 1.6 micrograms per cubic meter (ug/M3) to 5.1 ug/M3 (time-weighted average (TWA) over 17 hours) in areas where ceilings were constructed entirely from the contaminated tiles (mean = 2.7 ug/M3). The air in areas with PCB-containing tiles only around the perimeter of the ceiling had intermediate levels of PCBs (mean = 1.4 ug/M3, range = 1.1 ug/M3 to 1.8 ug/M3). The air in areas without any PCB-containing tiles had lower concentrations of PCBs (mean = 1.0 ug/M3, range = 0.9 ug/M3 to 1.0 ug/M3). A total of 17 air samples were analyzed.

In December 1986, after this initial environmental testing, local officials requested that the manufacturer replace the contaminated tiles as soon as possible. The school's staff and students temporarily moved to a new location in January 1987. Then, using isolation techniques similar to those used in asbestos abatement, the manufacturer removed approximately 30,000 square feet of ceiling tile and cleaned the remaining exposed surfaces. Air monitoring following tile removal showed diminished PCB concentrations. Mean PCB levels in areas where ceilings were constructed entirely from contaminated tiles decreased to 1.1 ug/M3. The mean concentration in areas with PCB-containing tiles only around the perimeter of the ceiling decreased to 1.3 ug/M3. Mean concentration in areas with no PCB-containing tiles decreased to 0.7 ug/M3. New ceiling tiles were then installed, and classes resumed February 17, 1987.

Additional monitoring in May 1987 showed further decreases in air concentrations of PCBs. Areas that had contained only contaminated ceiling tiles had an average concentration of 0.7 ug/M3; areas with contaminated tiles only around the perimeter had an average concentration of 0.8 ug/M3.

The school had been occupied for 16 years, and the average length of employment at that location for the 59 current staff members was 7 years. Serum samples from 73 current and former staff members were biologically monitored to determine whether increased PCB absorption could be detected. When the capillary column method of analysis (2) was used, the geometric mean of all PCB congeners was 1.2 micrograms per liter (ug/L) of blood (range = nondetectable to 12.2 ug/L).* In a Finnish study using the same laboratory method, the geometric mean for PCB congeners was 1.2 plus or minus 0.6 ug/L for people with no specific exposure to PCBs (2). Reported by: J Schmidt, PhD, Madison Dept of Public Health; M Rubenstein, PhD, W Sonzogni, PhD, Wisconsin State Laboratory of Hygiene; J Schirmer, MS, H Anderson, MD, Environmental Epidemiologist, Wisconsin Dept of Health and Social Svcs. Div of Field Svcs, Epidemiology Program Office; Div of Environmental Hazards and Health Effects, Center for Environmental Health and Injury Control; Office of the Director, National Institute for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Although epidemiologic evidence remains inconclusive (3), the International Agency for Research on Cancer has suggested that PCBs be considered "probable" human carcinogens (4), and animal studies indicate a potential for adverse reproductive effects (5-8). For airborne PCBs, the Occupational Safety and Health Administration has promulgated permissible 8-hour TWA exposure limits of 0.5 mg/M3 for PCBs containing 54% chlorine and 1 mg/M3 for PCBs containing 42% chlorine (9). The National Institute for Occupational Safety and Health (NIOSH), CDC, has recommended that occupational exposure by inhalation be limited to an 8-hour TWA less than or equal to1.0 ug total PCBs/M3 (the minimum reliably detectable concentration using the recommended sampling and analytical methods) (10). The initial environmental sampling at the school indicated that PCB concentrations in most working areas exceeded the NIOSH recommended limit. Although PCB air concentrations were lower immediately following removal of the contaminated tiles, they remained above the NIOSH recommended exposure limit. Several months following tile removal, repeat sampling for PCBs documented air concentrations below the NIOSH recommended limit.

The levels of PCBs in serum samples from staff members were similar to levels previously reported in various populations with no known specific exposures to PCBs (11,12). Environmental data were not available to characterize past exposures in the study population, nor were biological data available to characterize the staff's PCB body burden before exposure to the ceiling tiles. PCB in the serum samples could have been related primarily to accumulation from other sources such as diet (13), with some unknown additional contribution from exposures attributable to the contaminated ceiling tiles. The PCB blood values were well below levels that have been observed in occupational groups that have an increased prevalence of abnormal liver enzymes, one of the subtle effects suggestive of chronic PCB exposure (14).

References

  1. Centers for Disease Control. PCB contamination of ceiling tiles in public buildings--New Jersey. MMWR 1986;36:89-91.

  2. Luotamo M, Jarvisalo J, Aitio A. Analysis of polychlorinated biphenyls (PCBs) in human serum. Environ Health Perspect 1985;60:327-32.

  3. Brown DP, Jones M. Mortality and industrial hygiene study of workers exposed to polychlorinated biphenyls. Arch Environ Health 1981;36:120-9.

  4. International Agency for Research on Cancer. The evaluation of the carcinogenic risk of chemicals to humans: polychlorinated biphenyls and polybrominated biphenyls. Vol. 18. Geneva: World Health Organization, 1978.

  5. Villeneuve DC, Grant DL, Khera K, Clegg DJ, Baer H, Phillips WE. Fetotoxicity of a polychlorinated biphenyl mixture (Aroclor 1254) in the rabbit and in the rat. Environ Physiol 1971;1:67-71.

  6. Allen JR, Carstens LA, Barsotti DA. Residual effects of short-term, low-level exposure of nonhuman primates to polychlorinated biphenyls. Toxicol Appl Pharmacol 1974;30:440-51.

  7. Barsotti DA, Marlar RJ, Allen JR. Reproductive dysfunction in rhesus monkeys exposed to low levels of polychlorinated biphenyls (Aroclor 1248). Food Cosmet Toxicol 1976; 14:99-103.

  8. Allen JR, Barsotti DA. The effects of transplacental and mammary movement of PCBs on infant rhesus monkeys. Toxicol 1976;6:331-40.

  9. Centers for Disease Control. NIOSH recommendations for occupational safety and health standards. MMWR 1986;35(suppl 1S):27S.

  10. National Institute for Occupational Safety and Health. Criteria for a recommended standard: occupational exposure to polychlorinated biphenyls (PCBs). Cincinnati: US Department of Health, Education, and Welfare, Public Health Service, 1977; DHEW publication no. (NIOSH)77-225.

  11. Landrigan PJ. General population exposure to environmental concentrations of halogenated biphenyls. In: Kimbrough RD, ed. Halogenated biphenyls, terphenyls, naphthalenes, dibenzodioxins and related products. New York: Elsevier/North-Holland Biomedical Press, 1980:267-86.

  12. Wolff MS. Occupational exposure to polychlorinated biphenyls (PCBs). Environ Health Perspect 1985;60:133-8.

  13. Kreiss K, Roberts C, Humphrey HEB. Serial PBB levels, PCB levels, and clinical chemistries in Michigan's PBB cohort. Arch Environ Health 1982;37:141-7.

  14. Maroni M, Colombi A, Arbosti G, Cantoni S, Foa V. Occupational exposure to polychlorinated biphenyls in electrical workers. II health effects. Br J Ind Med 1981;38:55-60. *Laboratory detection limit = 0.6 ug/L.

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