Document ZwvgRxZeGGXzpGMmv8MkddV8

DEPARTMENT OP HEALTH AND HUMAN SERVICES Safety and Health Robert A. Taft Laboratories 4676 Columbia Parkway Cincinnati OH 45226-1998 July 31,2001 HETA 20010235 Brian Lewis PACE International Union 3340 Perimeter Hill Drive Nashville, Tennessee 37211 Dear Mr. Lewis; This letter is in response to your request to the National Institute for Occupational Safety and Health (NIOSH) for a Health Hazard Evaluation (HHE). Your request concerned exposure to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) among employees ofthe 3M Corporation in Cottage Grove, Minnesota. The request stated that employees had elevated blood fluoride levels. No health effects were noted.' The request apparently stemmed from worker concerns regarding recent institution o f engineering controls and the use o f personal protective equipment (PPE) among employees in the fluorochemical department In response to this request, I conducted telephone interviews with the Safety Director for the fluorochemical . department die local union president and the Director o f Occupational Medicine for 3M Corporation. This letter summarizes the findings o f my evaluation and gives you information addressing your concerns. B ackground . 3M, Cottage G row , M innesota The 3M facility in Cottage Grove houses several divisions, one ofw hich is the Specialty Materials Markets Group (previously known as the Chemical Division). The fluorochemical operations are one part o f the Specialty Materials Markets Group. Production of ammonium perfluorooctanoate (APFO), a synthetic surfactant began in Cottage Grove in 1947. APFO dissociates rapidly in aqueous solution to PFOA. APFO is a white powder, produced by an electrochemical process. It is then isolated and converted to a salt slurry, which in turn is converted to a salt cake, which is dried and packaged.1-2It was reported that the electrochemical cell used in the production of APFO is no longer running, but that drying and packaging of APFO still occurs in the Cottage Grove plant. Other fluorochemicals manufactured at Cottage Grove have perfluorooctane sulfonyl fluoride (POSF) as a precursor in a process similar to that described for PFOA. These compounds are transformed after absorption in the body to PFOS. Primary production o f PFOS compounds has been at 3M facilities in Antwerp, 3M Cottage Grove. HETA 20010235 Page 2 Belgium and Decatur, Alabama, with production in Cottage Grove being a much smaller operation. Therefore, published literature regarding health effects of PFOS have primarily included workers from Antwerp and Decatur, but should be applicable to Cottage Grove POSF production workers as well. POSF production was recently stopped in the Decatur facility and both POSF and APFO production are being phased out by 3M. There are currently approximately 33 workers in building 15, which is the main APFO production building and 10 to 20 workers in building 25, which the POSF production area. Voluntary medical surveillance has been performed biennially since the 1970s on fluorochemical workers. Participation rates in the medical surveillance program during the 1990s were 50-70%.2 Surveillance consists o f a medical questionnaire, spirometry, a chemistry panel, urinalysis, and vital signs. Total serum fluorine levels were measured until the early 1990s when methods became available to analyze serum for specific fluorochemicals. . ' Serum PFOA levels in Cottage Grove employees ranged from 0-80 parts per million (ppm) with a mean o f 5 ppm and a median of 1.1 ppm in 1993, from 0-114.1 ppm with a mean o f 6.8 ppm and a median o f 1.2 ppm in 1995, and from 0.1-81.3 ppm, with a mean of 6.4 ppm and a median o f 1.3 ppm in 1997.2 Serum PFOS levels in workers in 3M's Antwerp, Belgium, and Decatur, Alabama facilities ranged from 0-12.8 ppm (mean 2.49 ppm) in 1995 and 0.1-9.9 ppm (mean 1.75 ppm) in 1997.3 Levels in 3M employees in corporate offices averaged 0.05 ppm.4 Serum fluorine levels in the general population are reported to range from 0.01-0.13 ppm.9 Health Effects o fPFOA Animal studies demonstrate that PFOA is absorbed by ingestion, inhalation, and dermal exposure and is not metabolized. It is eliminated primarily through the urine and feces. PFOA has an estimated half-life o f 18-24 months in humans.5 PFOA increases the incidence o f liver, pancreas, and Leydig cell adenomas in lab animals.u The pancreatic adenomas may be due to mild elevations in cholecystokinin. PFOA also increased estradiol levels and decreased testosterone levels in rats.2 It caused marked hepatic effects in animals, including liver enlargement, focal necrosis, changes in lipid metabolism, and reduced levels o f lipids.4 Several epidemiologic studies have been conducted on PFOA workers at the Cottage Grove facility utilizing biennial medical surveillance data. Cholecystokinin levels were inversely related to serum PFOA levels, not elevated as seen in animal studies.2 While one study found positive associations between serum fluorine levels andxstradiol, prolactin, and thyroid stimulating hormone (TSH), and a negative relationship between serum fluorine and testosterone,7another did not find a significant relationship between serum PFOA levels and these hormones.1 Gilliland and Mandel reported that in unadjusted analyses, total serum cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDLX'serum glutamic pyruvic transaminase (SGPT), gamma glutamyl transferase (GGT), or serum glutamic oxaloacetic transaminase (SGOT) were not correlated with total serum fluorine levels.6 Ubel et. al. found no evidence o f adverse hepatic effects related to exposure to fluorochemicals.5 3M Cottage Grove. HETA 20010235 PageS A retrospective cohort mortality study of Chemical Division workers employed during the timw period 1948-1978 was performed.5 This included both APFO and POSF workers. There was no excess of all-cause mortality, cancer-specific mortality, or any other cause o f death. An update o f this cohort through 1983 revealed an excess o f prostate cancer mortality among men employed at least 10 years.* This was based on 4 prostate cancer deaths in the exposed workers. A further update of only PFOA workers through 1997 revealed no excess prostate cancer mortality risk, but did show a statistically nonsignificant increase in cerebrovascular disease mortality, although there was no dose-response relationship,9 Mortality rates for all causes and for all cancers were lower than expected in the general population. Health Effects o fPFOS PFOS concentrates in the liver and is excreted in both the urine and feces.3.PFOS has an estimated half-life in serum o f 1000-1500 days in humans.4 Exposure in animals results in decreased serum cholesterol levels and metabolic wasting.3 A study o f PFOS production workers did not reveal statistically significant changes in hepatic enzymes, cholesterol, or other lipoproteins at serum PFOS levels less than 6 ppm.3 Very few employees had serum PFOS levels higher that 6 ppm, therefore it was not possible to draw conclusions regarding exposure at those levels. . .* . In a cohort mortality study o f workers employed in the Alabama plant during the period 1961 1991, the all-cause mortality rates were statistically significantly lower than the general ' population.10 Rates were also lower for all cancers combined but elevated for cancer o f the lung, bronchus, and trachea, however, this elevation was not statistically significant Cohort mortality was updated through 1998, and the all-cause mortality rates were still significantly lower than the general population.11 However, there were three deaths from bladder cancer, resulting in a statistically significantly elevated rate. The author stated that it was unclear if these cases can be attributed to fluorochemical exposure, other occupational exposures, or non-occupadonal factors. Exposure C riteria The American Conference o f Governmental Industrial Hygienists' (ACGIH) Threshold Limit Value (TLV) for APFO is 0.01 milligrams per cubic meter o f air (mg/m3) as an 8-hour timeweighted average (TWA).12 There is no NIOSH Recommended Exposure Limit (REL) or U.S. Department o f Labor, Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for APFO. The exposure limit'for POSF set by 3M is 0.1 mg/m3. 3M developed an Occupational Biologic Limit Value (BLV) o f 5 ppm for PFOA in March o f 2000.13 A BLV is defined as the best estimate o f a level o f a chemical substance or its metabolite(s) in a biological fluid that if present, even on a chronic basis, would not be expected to pose, or correlate with, a significant risk of adverse health effects. Workers with serum PFOA levels between 5 and 10 ppm undergo medical surveillance every 6 months compared to every 2 years for routine surveillance, but are allowed to remain in the work area as long as serum levels 3M Cottage Grove. HETA 20010235 Page 4 decline on subsequent testing. Workers with levels > 10 ppm are removed from the area and monitored. 3M recently undertook an industrial hygiene assessment of the fluorochemical manufacturing process at the Cottage Grove facility. They identified work areas and tasks with potential exposures above the TLV for APFO. In response to these findings, process operator's job tasks were modified so that they were removed from the process areas and stationed primarily in an isolated control room. Entry into the process areas now requires PPE consisting o f full-face respirators (either supplied air or air purifying, depending on the area), coveralls (either Tyvek or rubber, depending on the area), nitrile gloves, and rubber boots. Access to the process areas is through a decontamination room. A large number o f tasks with potential exposures above the TLV for APFO were identified, and action taken to reduce exposure including exhaust ventilation, machine enclosure, improved housekeeping, and improved worker training. None o f the environmental air samples in non-process areas o f the building, including the control room and decontamination rooms, had APFO concentrations above 0.002 mg/m3. Engineering controls and PPE similar to those added in the APFO area are utilized in the POSF production areas. Conclusions and Recommendations .* 3M has an extensive medical surveillance and industrial hygiene monitoring program for fluorochemical workers at the Cottage Grove facility. Work areas have a combination of engineering controls, personal protective equipment, and administrative controls in place to reduce exposure to fluorochemicals. 3M has conducted or sponsored numerous animal and human health effects studies related to fluorochemical exposure. Most importantly, these fluorochemical manufacturing processes at Cottage Grove are being actively phased o u t Exposures to PFOA and PFOS at the levels encountered at 3M facilities have not been associated with adverse health effects. An qridemiologic study o f POSF workers has identified a possible relationship between occupational exposure to POSF and bladder cancer. It should be noted that mortality studies may underestimate the incidence o f bladder cancer since it is often not fatal. Conversely, other literature on the health effects o f POSF has not indicated that it is a bladder carcinogen. Given the above, no conclusion can be drawn at this time concerning occupational exposures to POSF and bladder cancer. I recommend that 3M continue current medical surveillance even after the phase-out o f these products is complete, in order to more clearly ascertain the potential health effects o f exposure to PFOA and PFOS. In addition, 3M should continue to update cohort mortality studies o f these employees. 3M should closely follow available epidemiologic and clinical information regarding the potential risk o f bladder cancer in workers exposed to POSF. Information available in the future may help determine if screening for bladder cancer among exposed employees would be useful. 3M Cottage Grove. HETA 20010235 Page 5 I hope this information is helpful to you. This letter serves to close the file for this project. For the purpose o f informing affected employees, copies o f this report should be posted by the employer in a prominent place accessible to the employees for a period o f 30 calendar days. If you have any further questions, please call me at (513) 841-4386. Sincerely yours, cc: Jeffrey Mandel, MD, MPH Elena H. Page, MJD., M.P.H. Medical Officer Assistance Branch Division o f Surveillance, Hazard Evaluations and Field Studies References: 1. Olsen GW, Gilliland FD, Burlew MM, Burris JM, Mandel JS, Mandel JH [1998]. An epidemiologic investigation o f reproductive hormones in men with occupational exposure to perfluorooctanoic acid. J Occup Environ Med. 40(7):614-622. 2. Olsen GW, Burris JM, Burlew MM, Mandel JH [2000]. Plasma cholecystokinin levels and hepatic enzymes, cholesterol, and lipoproteins in ammonium perfluorooctanoate production workers. Drug and Chemical Toxicology. 23(4):603-620. 3. Olsen GW, Burris JM, Mandel JH, Zobel LR [1999], Serum perfluorooctane sulfonate and hepatic and lipid clinical chemistry tests in fluorochemial production workers. J Occup Environ Med. 41(9).-799-806. . '! 4. 3M [2000]. Draft initial assessment report: perfluorooctane sulfonic acid and its salts. Submitted to the United States Environmental Protection Agency. ' , 5. UbelFA, Sorenson SD, Roach DE [1980]. Health status o fplant workers exposed to fluorochemicals - a preliminary report Am Ind Hyg Assoc J 41:584-589. 6. Gilliland FD, Mandel JS [1996]. Serum perfluorooctanoic acid and hepatic enzymes, lipoproteins, and cholesterol: a study o f occupationally exposed men. Am J Ind Med. 29:560 568. 7. Gilliland FD [1992]. Fluorocarbons and human health: studies in an occupational cohort Doctoral dissertation, University o f Minnesota. In: Olsen GW, Gilliland FD, Burlew MM, Burris JM, Mandel JS, Mandel JH [1998]. An epidemiologic investigation o f reproductive hormones in men with occupational exposure to perfluorooctanoic acid. J Occup Environ Med. 40(7) :614-622. 8. Gilliland FD, Mandel JS [1993]. Mortality among employees o f a perfluorooctanoic acid production plant J Occup Environ Med. 35(9):950-954. 9. Alexander BH [2001]. Mortality study o f workers employed at 3M Cottage Grove facility. University o f Minnesota School o f Public Health. 10. Mandel JS, Johnson RA [1995]. Mortality study o f employees at 3M plant in Decatur, Alabama. ln:3M [2000]. Draft initial assessment report: perfluorooctane sulfonic acid and its salts. Submitted to the United States Environmental Protection Agency. 11. Alexander BH [2001]. Mortality study o f workers employed at 3M Decatur facility. University o f Minnesota School o f Public Health. 12. ACGIH [2001]. 2001 TLVs and BEIs: threshold limit values for chemical substances and physical agents. Cincinnati, OH: American Conference o f Governmental Industrial Hygienists. . 13. 3M [2000]. Documentation o f an occupational biologic limit value for perfluorooctanoate.