D. Arfsten, K. Still, W. Jederberg, Naval Health Research Center Toxicology Detachment, Wright-Paterson AFB, OH; B. Larcom, Office of the Secretary of the Air Force, Washington, DC.
PCBs have been identified on surfaces and in component materials and equipment from inactive U.S. Navy nuclear submarines commissioned prior to 1970. Health risks associated with PCBs present onboard submarines were estimated for hypothetical crewmembers and shipyard workers. Median noncancer hazard quotients for shipyard workers and submarine crew ranged between 0.4–54.6 with the highest quotients estimated for unprotected shipyard workers. Median cancer risk estimates ranged from 7.3 x 10-6 to 1.1 x 10-3 with the highest estimated risk calculated for unprotected shipyard workers. Our findings suggest that PCB surface concentrations found onboard inactive nuclear submarines commissioned prior to 1970 may be high enough to constitute a possible risk to the health of persons involved in the dismantling of Navy submarines if PCB exposure is not minimized. Potential sources of uncertainty in our risk assessment include the correlation between PCB contamination levels on inactive versus active nuclear submarines vessels, the relationship between wipe sample concentrations and human exposure, dermal contact frequency with PCB-contaminated surfaces, carcinogenicity of PCBs in humans, and uncertainties inherent with the PCB cancer slope factor and oral RfD. Our findings support Navy policy that shipyard workers should wear personal protective equipment when PCB contamination is suspected or has been identified and that IH surveys should continue to identify sources of PCB contamination onboard vessels and reduce PCB contamination to concentrations that are reasonably achievable.
S. Henn, WESTAT, Cincinnati, OH; W. Tankersley, Oak Ridge Associated Universities, Oak Ridge, TN; D. Utterback, NIOSH, Cincinnati, OH.
A qualitative exposure assessment was conducted for a cohort mortality study of 4015 chemical laboratory workers (CLWs) employed between 1943 and 1984 at three Department of Energy sites in Oak Ridge, Tenn. Previous studies of CLWs were on members within associations, where exposure assessment was not feasible, or from industrial companies where laboratory and production workers were combined.
Since industrial hygiene records were unavailable for all three sites, duration of employment was used as a surrogate for the magnitude of exposure. Potential exposure indices were calculated for each worker using number of days employed at the sites along with weighting factors for job title and decade. Workers were then separated into equal exposure categories of low, medium, or high using the 33rd and 66th percentiles. 590 unique job titles indicative of a CLW were collapsed into 14 general job titles. Through interviews with current and retired workers along with organizational charts, responsibilities, and tasks for each of the collapsed job titles were assembled. Weighting factors of 0.01, 0.006, 0.003, and 0.0005 were assigned to these job titles representing the frequency of hands-on activities with chemicals encountered. Job titles with 100% hands-on activities, like lab technicians, received the highest factor of .01, while job titles such as lab clerks received the lowest factor of .0005. Also, weighting factors of 5, 2.5, 1.5, and 1 were assigned for each decade to account for improvements in laboratory technique, advancements in instrumentation, improvement in engineering controls, and increased safety awareness through time. Additionally, exposures were classified into four categories based on departmental function and chemical usage: 1) inorganic, 2) inorganic with routine mineral acid use, 3) organic, and 4) a combination of the previous three categories. Estimated magnitude and categories of chemical exposures will be used in epidemiologic risk models for this cohort.
L. Chuh Lun, T. Perng Jy, National Cheng Kung University Medical College, Tainan, Taiwan, Republic of China.
This study illustrates a systematic analytical method for determining the most significant environmental factor associated with thermal stresses imposed on dyeing and finishing workers. In this study, four dyeing and finishing workplaces were selected for conducting environmental monitoring. For each selected workplace, we measured its ambient air temperature (Ta), globe temperature (Tg), air velocity (Va), and relative humidity (RH) continuously during one work shift. During the sampling period, a total of 21 workers were chosen from the above 4 workplaces for estimating their metabolic rates by using a real-time heart rate monitor. All measured data were applied to a predicted heat strain model proposed by ISO in 2003 to determine the allowable exposure time (AET) for each selected worker. The sensitivity of each measured environmental parameter on determining AETs was estimated by using the Monte Carlo method. Results show that the mean Ta, Tg, RH, and Va measured from the furnace of the five selected casting plants were 37.63 ± 1.29°C, 38.53 ± 1.39°C, 55.53 ± 3.35%, and 0.36 ± 0.11 m/s, respectively. Workers metabolic rates were found ranging from 116 to 193 W/m2. The AETs for the four workplaces were determined by heat storage criteria, i.e. the time when predicted rectal temperature reaches to 38°C, and the average AETs were 55.8, 49.8, 83.3, and 114.0 minutes, respectively. We further conducted the Monte Carlo sensitive analysis and found that RH was the most significant environmental factor that affected furnace workers’ AETs. The above result suggests that the control of the environmental factor of RH would be the most efficient way to reduce workers’ thermal stresses.
T. Perng Jy, L. Wen Jhy, H. Sheng Lung, National Cheng Kung University, Tainan, Taiwan, Republic of China; S. Minlinag, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan, Republic of China; S. Tung Sheng, Institute of Occupational Safety and Health, Council of Labor Affairs, Taipei, Taiwan, Republic of China; C. Guo Ping, Cheng Shiu University, Tainan, Taiwan, Republic of China.
This study set out to characterize the contents of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) contained in the workplace atmosphere of a sintering plant located in southern Taiwan. Static samplings were conducted on the four sampling sites of the raw materials inlet (site A), sintering grate (site B), rough roll shredder (site C), and control room (site D) inside the sinter plant and on the surrounding ambient environments outside the sinter plant for comparison. We found that workplace atmosphere had higher total suspended particle and PCDD/F concentrations (in term of I-TEQ) (= 98–4969 µg Nm-3 and 0.16–2.14 pg I-TEQ Nm-3, respectively) than the surrounding ambient air (= 33.3 µg Nm-3 and 0.05 pg I-TEQ Nm-3, respectively). The above results suggest that workers’ exposures were much more significant than the inhabitants living nearby the sinter plant. For PCDD/F congener profiles, because high-chlorinated congeners such as OCDD and OCDF were reduced after raw materials sintered, it was not so surprising to see that low-chlorinated congeners such as 2,3,7,8-TeCDF; 1,2,3,7,8-PeCDF; and 2,3,4,7,8-PeCDF became dominant. The PCDD/F contents contained in particles collected from the control room (15.85 ng g-1 and 1.19 ng I-TEQ g-1) were higher than those collected from the other three sampling sites (1.43–14.3 ng g-1 and 0.1–1.07 ng I-TEQ g-1). The above results clearly indicate that the fine fraction of the process fugitive particles that penetrate into the control room, although their concentrations were not as high as those in the sintering process, would significantly increase the health risk arising from PCDD/F exposures.
J. Marshall, ExxonMobil Corp., Baton Rouge, LA.
Emergency or unplanned air monitoring is difficult under the best of circumstances due to several reasons. Typically, the window of opportunity to collect these samples is limited so all aspects of air monitoring must work efficiently. In addition, most facilities have limited resources available for air monitoring even though air-monitoring data may be critical for certain decisions. These decisions may include appropriate PPE, location of staging areas, site or community evacuations, etc.
This is a review of successful methods learned at a major refining/chemical manufacturing facility for on site/community air monitoring during unplanned events. It provides a process to identify necessary information, equipment, and training that can eliminate many of the obstacles for air monitoring during these types of events.
Key components included are methods to summarize facility hazards, monitoring methods, and suggestions for selecting the appropriate equipment. Monitoring methods play a critical role for efficient and accurate samples; these are discussed with suggestions for preferred methods. Several examples will be used to illustrate these methods as well as methods to identify appropriate community sample locations.
During an unplanned/emergency event, useful (quick, accurate) air-monitoring data is usually possible. Preparation and planning can provide air-monitoring results that are useful to the emergency response teams, site personnel, and community.
L. Naeher, C. Carlton, The University of Georgia, Athens, GA; D. MacIntosh, Environmental Health & Engineering Inc., Newton, MA; D. Shea, USDA Forest Service, New Ellenton, SC; G. Achtemeier, USDA Forest Service, Athens, GA.
In this study of occupational exposure to smoke from forest fires and respiratory health, we followed a cohort of 12 forest fighters over a 5-week study during the prescribed burn season in winter 2003 in a Southeastern U.S. forest. Daily pre- and post-shift spirometry (FEV1, FVC, PEF) was done on each subject and a daily post-shift exposure and respiratory symptoms questionnaire (e.g, cough, phlegm, itchy eyes) and time activity diary was collected for each subject for the duration of the study. Fifty-four individual personal work-shift PM2.5 samples were collected during burn activities and nine during nonburn activities (controls). Over the 5-week study, there were 9 days of prescribed burn activity when fire fighters were sampled, with an average of 5.4 fire fighters monitored per burn (for an average duration of 7.9 hrs/sample). Burn sizes ranged from 1 to 2042 acres (average = 613.1 acres). The overall average PM2.5 for the 54 burn activity samples was 385.5 ug/m3 (range 21.3–2462 ug/m3 ). In addition, daily PM2.5 24-hr measures were collected during the study period as a measure of background PM2.5 in the area. The exposure assessment component of this study is presented elsewhere (Carlton et al., AIHA 2004). The epidemiological component of this study is presented herein. Using a Mixed Linear Random Coefficients Model, we investigate the relationship between daily PM2.5 exposures (actual, estimated, and predicted) on burn and nonburn days with respiratory function and health symptoms. Data from this study suggest that prescribed forest burn-related occupational exposures to PM2.5 are of concern for forest fighters and warrant further exposure and health effects studies.
Posted May 30, 2004