Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 97-0265-2781, 2000 Feb; :1-18
In July 1997, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation and technical assistance (HHE) from the United Steel Workers of America (USWA) to investigate possible respiratory problems at AFG Industries in Bridgeport, West Virginia. AFG Industries produces sheet glass from raw materials. The respiratory health concerns cited in the request included breathing problems and irritation including nose bleeds; and exposure concerns included adipic acid, crystalline silica, asbestos, sulfur dioxide (SO2), and nuisance dusts. A walk-through survey was conducted on September 23, 1997. Two industrial hygiene surveys were conducted on May 18 and June 10, 1998. During these surveys, samples were collected for respirable dust and respirable crystalline silica, adipic acid, and SO2 Medical records were reviewed from 10 workers who complained of work-related respiratory illness. A self-administered questionnaire was mailed to all employees during August and September of 1998. Participants were asked about upper and lower respiratory symptoms, skin and eye symptoms, personal health history, work history, work activities, and tobacco use. Four personal and two area samples were collected for respirable dust and respirable crystalline silica; all samples were collected from the silo tower area (the hot end of the plant). The respirable dust samples ranged from 0.31 mg/m^3 to 4.86 mg/m^3. The personal crystalline silica concentrations ranged from 0.09 mg/m^3 to 0.35 mg/m^3. The workers assigned to the silo tower used respiratory protection by company policy. The disposable respirators used by workers had an assigned protection factor (APF) of 10 and, when used properly, would reduce exposures ten-fold. Thus, these crystalline silica exposures, if attenuated by proper respirator use, would be below the existing Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PEL), the NIOSH Recommended Exposure Limit (REL), and The American Conference of Governmental Industrial Hygienists (ACGIH), Threshold Limit Exposure Values (TLVs). However, the results from crystalline silica sampling demonstrate the potential for overexposure among workers in the silo tower area if respirators are not used or used improperly. Fifteen total dust samples were collected for adipic acid in air including 14 personal samples and 1 area sample. Adipic acid was used in the cold end of the plant. The total dust concentrations from this area ranged from 0.25 mg/m^3 to a high of 1.68 mg/m^3. The total adipic acid concentrations ranged from 0.01 mg/m^3 to a high of 0.89 mg/m^3; the mean adipic acid concentration from the total dust samples was 0.10 mg/m^3 with a standard deviation (SD) of 0.22 mg/m^3. The adipic acid content of the airborne total dust samples ranged from 3% to 53% by weight; the mean percent by weight adipic acid concentration in airborne total dust was 13.8% with a SD of 12%. These concentrations were below the existing ACGIH TLV. Sulfur dioxide was not detected in any of the seven short term area samples taken. Plant management reported that asbestos materials had been removed form the plant and no friable asbestos insulation was observed during this survey. Of the 312 questionnaires mailed, 144 (46%) were returned; 138 had complete information and were used for the analysis. Results of self-reported respiratory symptoms showed cough in the morning by 42%, phlegm in the morning by 47%, chest tightness by 53%, and wheeze by 52%. Symptoms were also stratified by smoking status and job category; results indicated that lower respiratory symptoms increased among former smokers from the hot end. Overall, work-related health problems were reported in 47% of the workers. These conditions included upper respiratory symptoms by 60%, mucosal irritation by 26%, musculoskeletal by 18%, and hearing loss by 14%. Overall nasal bleeding was reported by 25% (35 of 138) of the workers. Stratification by job category indicated that 30% of cold end workers reported nasal bleeding, as did 23% of the hot end workers, 22% of the warehouse workers, and 7% of maintenance workers. The frequency of nose bleeding was reported 1 to 4 times a year in 74% of the cases. Overall skin irritation was reported in 43% (59 of 138) of the workers. Symptoms by job category indicated that 47% of cold end workers reported skin irritation, as did 69% of the hot end workers, 17% of the warehouse workers, and 36% of maintenance workers. Overall eye irritation was reported by 71% (98 of 138) of the workers. Symptoms by job category indicated that 75% of worker in the cold end reported eye irritation, 69% of hot end workers, 57% of the warehouse workers, and from 79% of maintenance workers. These findings suggest a high prevalance of mucosal irritation symptoms among plant workers in both cold end and hot end areas. Thirteen cases of alleged pneumoconiosis were identified in the OSHA 200 logs; this prompted a review of the medical records. Ten medical records were obtained. Of these, the average age was 42 years. The tenure in the glass industry was 21 years. Radiographic evaluations conducted by certified B Readers from a medical group contracted by the company as well as NIOSH's B Reader physician did not document any finding related with occupational pneumoconiosis. A review of AFG's OSHA 200 log from 1996 included 63 cases of musculoskeletal injuries, seven cases of alleged pneumoconiosis, three cases of hearing loss, and two eye related injuries. During the first nine months of 1997, 41 cases of musculoskeletal injuries, one case of eye injury, and one case of SO2 inhalation were reported.