Historical Exposure Estimates Research Articles

Diesel Exhaust Exposure and Cause-Specific Mortality in the Diesel Exhaust in Miners Study II (DEMS II) Cohort.

With the exception of lung cancer, the health effects associated with diesel exhaust for other cancers and nonmalignant health outcomes are not well understood. We extended the mortality follow-up of the Diesel Exhaust in Miners Study, a cohort study of 12,315 workers, by 18 y (ending 31 December 2015), more than doubling the number of observed deaths to , to evaluate associations between mortality and diesel exhaust exposure. Quantitative estimates of historical exposure to respirable elemental carbon (REC), a surrogate for diesel exhaust, were created for all jobs, by year and facility, using measurements collected from each mine, as well as historical measurements. Standardized mortality ratios (SMRs) and hazard ratios (HRs) were estimated for the entire cohort and by worker location (surface, underground). We observed an excess of death for cancers of the lung, trachea, and bronchus (; ; 95% CI: 1.13, 1.37). Among workers who ever worked underground, where the majority of diesel exposure occurred, excess deaths were evident for lung, trachea, and bronchus cancers (; ; 95% CI: 1.11, 1.42). Several nonmalignant diseases were associated with excess mortality among workers ever-employed underground, including ischemic heart disease (; 95% CI: 1.00, 1.16), cerebrovascular disease (; 95% CI: 1.04, 1.43), and nonmalignant diseases of the respiratory system (; 95% CI: 1.01, 1.26). Continuous 15-y lagged cumulative REC exposure was associated with increased lung cancer risk (; 95% CI: 1.24, 3.03), but the risk declined at the highest exposures (; 95% CI: 0.74, 2.26). We also observed a significant trend in non-Hodgkin lymphoma (NHL) risk with increasing 20-y lagged cumulative REC (; 95% CI: 1.00, 9.79; ). Increased risks of lung cancer mortality observed in the original study were sustained. Observed associations between diesel exposure and risk of death from NHL and the excesses in deaths for diseases of the respiratory and cardiovascular system, including ischemic heart disease and cerebrovascular disease, warrant further study and provide evidence of the potential widespread public health impact of diesel exposure. https://doi.org/10.1289/EHP12840.

Reconstructing historical exposures to elongate mineral particles (EMPs) in the taconite mining industry for 1955–2010

As part of ongoing epidemiological studies for assessing the association between exposure to dust from taconite operations and the development of respiratory diseases, the goal of this study was to reconstruct the exposures of workers to elongate mineral particle (EMP) in the Minnesota taconite mining industry from 1955–2010. Historical NIOSH-7400 and equivalent EMP personal exposure data were extracted from two sources: (1) the Mine Safety and Health Administration (MSHA) online database recorded for all inspection results since 1978 with 655 EMP monitoring records from 1978–2010 for 13 MSHA Mine IDs associated with this study; and (2) the mining companies’ internal monitoring reports contained 96 personal EMP exposure records. NIOSH-7400 EMP personal exposures were measured for workers in different jobs in all active mines in 2010 by obtaining 1,285 personal samples. After data treatment, all data were grouped into seven mines and eight departments. Within each mine-department, the yearly EMP mean concentration in f/cc for each year of operation was predicted using two approaches. The performance of two approaches varied by situation. The assumptions underlying each approach described in this article have limitations. A linear regression based on limited historical measurements and those made in 2010–2011 (Approach 1) does not yield reasonable and plausible values of the slope. Approach 2 assumes that the EMP and the respirable dust in the same department share the same historical time trend. This approach allowed us to avail of the more reasonable slope estimates from the historical respirable dust data set and yielded more plausible historical exposure estimates for most locations. This work with two different job exposure matrix (JEMs) provides a unique research opportunity to study the potential impact of exposure assessment to epidemiological results. Both JEMs are being used to assess associations between EMP and respiratory disease in epidemiological studies.

The importance of historical data in simulating malaria epidemiology and control interventions: application to multiple sites in Madagascar

Planning malaria interventions requires the prediction of likely impacts of different intervention strategies. Simulation models can provide such predictions but weak information about pre-control levels of transmission, intervention coverage and access to care often makes it challenging to correctly parameterize them. We consider a number of low malaria transmission sites in Madagascar, with available historical prevalence and entomological inoculation rate (EIR) estimates (by mosquito sampling), giving disparate estimates of historical exposure. Information about implementation of Long Lasting Insecticide Nets (LLINs) and Indoor Residual Spraying (IRS), and access to healthcare, collated from malaria surveys and on-going cross-sectional studies were used to parameterise simulations of malaria transmission, prevalence and burden within the OpenMalaria platform. Multiple parameterisations were considered using various sources of data for pre-intervention transmission level, intervention coverage and access to healthcare. In some sites the simulated impact of existing vector control programs matches reasonably well the malaria prevalence measured in a recent national survey. In others it predicts lower than observed prevalence, very likely because the models do not capture residual local transmission foci. The simulations suggest that the most cost-effective vector control strategy would be to scale-up LLINs or IRS only, depending on the transmission level. Indeed, preliminary results show no additional benefit of IRS where LLINs were used. These preliminary results suggest that historical prevalence data, combined with current coverage information are potentially adequate for planning intervention strategies. The outcome of intervention scale-up is essentially unpredictable if baseline information is poor. Reproducing the observed epidemiology of malaria through simulations both provides confidence in the use of the model but serves as a basis for prospective studies that support decision-making, including cost-effectiveness analyses.

0330 A Study of Radiographic Abnormalities in Minnesota Taconite Workers

ObjectivesA limited number of studies have been conducted in the taconite industry, typically without detailed exe posure information. We assessed occupational exposure to elongate mineral particles (EMP) in association with...

Imputation method for lifetime exposure assessment in air pollution epidemiologic studies

BackgroundEnvironmental epidemiology, when focused on the life course of exposure to a specific pollutant, requires historical exposure estimates that are difficult to obtain for the full time period due to gaps in the historical record, especially in earlier years. We show that these gaps can be filled by applying multiple imputation methods to a formal risk equation that incorporates lifetime exposure. We also address challenges that arise, including choice of imputation method, potential bias in regression coefficients, and uncertainty in age-at-exposure sensitivities.MethodsDuring time periods when parameters needed in the risk equation are missing for an individual, the parameters are filled by an imputation model using group level information or interpolation. A random component is added to match the variance found in the estimates for study subjects not needing imputation. The process is repeated to obtain multiple data sets, whose regressions against health data can be combined statistically to develop confidence limits using Rubin’s rules to account for the uncertainty introduced by the imputations. To test for possible recall bias between cases and controls, which can occur when historical residence location is obtained by interview, and which can lead to misclassification of imputed exposure by disease status, we introduce an “incompleteness index,” equal to the percentage of dose imputed (PDI) for a subject. “Effective doses” can be computed using different functional dependencies of relative risk on age of exposure, allowing intercomparison of different risk models. To illustrate our approach, we quantify lifetime exposure (dose) from traffic air pollution in an established case–control study on Long Island, New York, where considerable in-migration occurred over a period of many decades.ResultsThe major result is the described approach to imputation. The illustrative example revealed potential recall bias, suggesting that regressions against health data should be done as a function of PDI to check for consistency of results. The 1% of study subjects who lived for long durations near heavily trafficked intersections, had very high cumulative exposures. Thus, imputation methods must be designed to reproduce non-standard distributions.ConclusionsOur approach meets a number of methodological challenges to extending historical exposure reconstruction over a lifetime and shows promise for environmental epidemiology. Application to assessment of breast cancer risks will be reported in a subsequent manuscript.

Re: The Diesel Exhaust in Miners Study: A Nested Case–Control Study of Lung Cancer and Diesel Exhaust and a Cohort Mortality Study With Emphasis on Lung Cancer

When the Diesel Exhaust in Miners Study (DEMS) was initiated in the early 1990s, one key goal was to develop quantitative estimates of historical exposure to diesel exhaust (DE). It was recognized that the epidemiological results would only be as robust as the exposure assessment upon which they are based. Respirable elemental carbon (REC), a surrogate of diesel exhaust particulates, was selected as the primary exposure variable, yet in very recent years investigators turned to an alternative exposure assessment methodology that relied instead on carbon monoxide (CO) measurements. Assumptions were also made regarding engine horsepower and mine ventilation to “back

Sensitization and chronic beryllium disease at a primary manufacturing facility, part 2: validation of historical exposures

The aim of this study was to evaluate the validity of a job exposure matrix (JEM) constructed for the period 1994-1999. Historical exposure estimates (HEE) for the JEM were constructed for all job and year combinations by applying temporal factors reflecting annual change in area air measurements (1994-1998) to the personal baseline exposure estimates (BEE) collected in 1999. The JEM was generated for an epidemiologic study to examine quantitative exposure-response relationships with sensitization and chronic beryllium disease. The validity of the BEE and HEE was evaluated by comparing them with a validation dataset of independently collected personal beryllium exposure measurements from 1999 and 1994-1998, respectively. Agreement between the JEM and validation data was assessed using relative bias and concordance correlation coefficients (CCC). The BEE and HEE overestimated the measured exposures in their respective validation datasets by 8% and 6%, respectively. The CCC reflecting the deviation of the fitted line from the concordance line, showed good agreement for both BEE (CCC=0.80) and HEE (CCC=0.72). Proportional difference did not change with exposure levels or by process area and year. Overall, the agreement between the JEM and validation estimates (from combined HEE and BEE) was high (CCC=0.77). This study demonstrated that the reconstructed beryllium exposures at a manufacturing facility were reliable and can be used in epidemiologic studies.

Sensitization and chronic beryllium disease at a primary manufacturing facility, part 1: historical exposure reconstruction

Previous epidemiologic studies of beryllium sensitization (BeS) and chronic beryllium disease (CBD) have reported inconsistent exposure-response relationships, likely due to exposure misclassification. The objective of this study was to develop historical estimates of size-selective personal exposure to beryllium for an epidemiologic study. In 1999, a cross-sectional survey of workers hired after 1 January 1994 was conducted at a beryllium production facility. Personal exposure data from two air sampling surveys conducted in 1999 were used to obtain total, respirable, and submicron particle baseline exposure estimates (BEE) for a job-exposure matrix (JEM). General area air samples collected from 1994-1999 were used to estimate annual changes in exposures (temporal factors) for 24 different process areas. Historical exposure estimates (HEE) were calculated by applying the temporal factors to the BEE. Workers were assigned HEE based on their work history, and their historical exposure profile was summarized as cumulative, average, or highest-ever job exposure. Changes in exposure over a 6-year period were observed in 10 of the 24 process areas with an overall mean decline of 18% per year. The overall total exposure for study participants over their work tenure ranged from: 0.001-34.44 μg/m(3)-year, 0.01-16.26 μg/m(3), and 0.01-17.54 μg /m(3) for cumulative, average, and highest-ever job, respectively. For respirable exposures, the ranges were: 0.001-15.54 μg/m(3)-year, 0.01-3.56 μg/m(3), 0.01-5.54 μg /m(3) for cumulative, average, and highest-ever job, respectively. Using this JEM, exposure-response relationships for BeS and CBD can be explored over a range of exposure metrics such as total, respirable, and submicron beryllium mass concentrations, including summary measures such as cumulative, average, or highest exposures, with the ultimate objective of elucidating a quantitative exposure-response relationship.

Estimation of particulate mass and manganese exposure levels among welders.

Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures in absence of individual measurement data.

Development of historical exposure estimates of cosmic radiation and circadian rhythm disruption for cohort studies of Pan Am flight attendants

The National Institute for Occupational Safety and Health is conducting cohort studies of flight crew employed by the former Pan American World Airways company (Pan Am) as part of an effort to examine flight crew workplace exposures and health effects. Flight crew are exposed to elevated levels of cosmic radiation and to disruption of circadian rhythm when flying across multiple time zones. Methods exist to calculate cosmic radiation effective doses on individual flights; however, only work histories which provided an employee's domicile (home base) history rather than a record of every flight flown were available. We developed a method for estimating individual cumulative domicile-based cosmic radiation effective doses and two metrics for circadian rhythm disruption for each flight attendant: cumulative times zones crossed and cumulative travel time during the standard sleep interval. The domicile-exposure matrix developed was used to calculate exposure estimates for a cohort mortality study of former Pan Am flight attendants.

Morbidity in former sawmill workers exposed to pentachlorophenol (PCP): A cross‐sectional study in New Zealand

From 1950 to 1990 pentachlorophenol (PCP) was used widely in the New Zealand sawmill industry, and persistent claims of long-term health effects have been made. We surveyed surviving members of a cohort enumerated to study mortality in sawmill workers employed from 1970 to 1990. Estimates of historical exposure were based on job titles held, using the results of a PCP biomonitoring survey conducted in the 1980s. The survey involved interviews and clinical examinations, with interviewers and examiners blinded to exposure status. Of the 293 participants 177 had not been exposed, and of the 116 exposed all but 10% had low or short-term PCP exposure. Nevertheless, a number of significant associations between PCP exposure and the prevalence of various symptoms were observed including associations between: (i) exposure levels and self-reported tuberculosis, pleurisy or pneumonia (P < 0.01) and a deficit in cranial nerve function (P = 0.04); (ii) duration of employment and thyroid disorders (P = 0.04), and neuropsychological symptoms including often going back to check things (P = 0.04), low libido (P = 0.02) and heart palpitations (P = 0.02), and a strong dose-response trend for frequent mood changes without cause (P < 0.01); and (iii) cumulative exposure and frequent mood changes without cause (P = 0.02), low libido (P = 0.04), and in the overall number of neuropsychological symptoms reported (P = 0.03). PCP exposure was associated with a number of physical and neuropsychological health effects that persisted long after exposure had ceased.

Benzene exposure in the shoemaking industry in China, a literature survey, 1978–2004

This article presents a summary of benzene exposure levels in the shoemaking industry in China reported in the Chinese medical literature between 1978 and 2004. A comprehensive search identified 182 papers reporting such exposure data. These papers could be classified into two categories: benzene poisoning case reports and industrial hygiene surveys. From each paper, the following information was abstracted whenever available: location and year of occurrence, occupation and/or task involved, benzene content in adhesives/solvents, work environment, working conditions, working hours, diagnosis, and air monitoring data of benzene. A total of 333 benzene measurements (88 averages, 116 minimums, 129 maximums) in the shoemaking industry were reported in the 182 papers identified. The data were analyzed in terms of geographical location, time period, type of ownership (state, township, or foreign), type of report (benzene poisoning reports vs. industrial hygiene surveys), and job title (work activity) or process. The reported data covered a wide range; some measurements were in excess of 4500 mg/m 3. Thirty-five percent of the reported benzene concentrations were below 40 mg/m 3, which was the national occupational exposure limit (OEL) for benzene between 1979 and 2001. The remaining 65% measurements, which exceeded the national OEL in effect at the time, and were distributed as follows: 40–100 mg/m 3, 11%; 100–300 mg/m 3, 21%; 300–500 mg/m 3, 13%; and 500+ mg/m 3, 20%. However, only 24% of the reported measurements after 2002 were below 6 mg/m 3, i.e., Permissible Concentration-Time Weighted Average (PC-TWA) and 10 mg/m 3, i.e., Permissible Concentration-Short Term Exposure Limit (PC-STEL), the newly amended benzene OELs in effect after May 2002. The data demonstrated that the majority of the facilities in the shoemaking industry reported in the literature were not in compliance of the OEL for benzene in effect at the time. Overall, the data show a clear downward trend of benzene exposure levels over the years, particularly after the introduction of the new lower OEL in 2002. Even though substantially lower when compared to levels in the past, current benzene exposure measurements from the literature review suggest that many facilities in the shoemaking industry in China have benzene concentrations that are still above the new OEL. The reported data, stratified by job, year and survey reason, can be used as part of the information and analysis for developing a job-exposure matrix in retrospective exposure assessment and thus may be part of the information used in developing historical exposure estimates in epidemiologic studies of shoe workers.

Beryllium Exposure Data: Rosenman et al. Respond

We thank Kolanz for his careful reading of our article (Rosenman et al. 2005). An erratum correcting the problem he noted appears on page A214. How do these corrected numbers change our results? More chronic beryllium disease (CBD) and sensitization occurred with exposure below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 2 μg/m3 (OSHA 2005) than we previously reported, but no CBD or sensitization was found below the Department of Energy (DOE) guidelines of 0.2 μg/m3 (DOE 1999) or the even more protective level proposed by the American Conference of Governmental Industrial Hygienists (ACGIH 2005) of 0.02 μg/m3. There was an insufficient number of individuals—only three, and they were all normal—to assess the safety of the DOE guidelines or proposed ACGIH level. Our previously reported findings regarding chemical and physical form—that sensitized individuals compared with individuals with CBD had higher exposure to beryllium in a soluble form and to fumes of beryllium (Rosenman et al. 2005)—remain unchanged. However, the mean peak exposure for the sensitized group in our Table 8, the mean nonsoluble exposure for the sensitized group in Table 9, and the mean dust exposure for the sensitized group and mean fume exposure for the CBD group in Table 10 were no longer significantly different, whereas the peak fume exposure for the CBD group was now significantly different in Table 10. Having acknowledged and corrected the error pointed out by Kolanz, we take strong exception to his statement that “the study cannot sustain conclusions about the degree of risk associated with lower levels of exposure,” by which he means less than the OSHA PEL of 2 μg/m3 (OSHA 2005). One of Kolanz’s criticisms of our article (Rosenman et al. 2005) is that the daily weighted average (DWA) represented the daily exposure based on data averaged over 3 months. Breslin and Harris (1958) conducted a time study, which was updated as activities and location changed for each job title. During a 3-month period, three or more samples were collected and standardized to represent the general area where each person worked, and in some cases the breathing zone during work activities. The arithmetic average of the samples for each location/type was then calculated and weighted by time (Breslin and Harris 1958). Use of these summed weighted values, divided by the shift duration, is consistent with the American Industrial Hygiene Association (AIHA) exposure assessment guidance (Mulhausen and Damiano 1998) cited by Kolanz. We agree with Kolanz’s comment about the use of the flame spectroscopy method of chemical analysis and its general limit of detection of 0.1 μg/m3. In the job exposure matrix and task exposure matrix developed to support this project (Chen 2001), no exposure estimate was < 0.1 μg/m3, so this issue would have no effect on our results. Kolanz also takes exception with our estimates of mean exposures, stating that these values were derived by triple averaging. We derived the mean exposures as follows: for a given worker in a given job in a given year, we multiplied the number of days worked in that year for that worker by our best estimated DWA for that job in that year. We then summed those values over all jobs for that worker to derive that worker’s cumulative exposure. Next we divided that worker’s cumulative exposure by the total number of days worked in his/her job history to derive that worker’s mean exposure. Thus, there is only one averaging on each worker and a subsequent averaging for the population. We used multiple metrics (cumulative, average, peak job, and peak task for total exposure; exposure by chemical form; and exposure by physical form) to characterize not only the central tendencies of the exposures but also their extreme excursions. We stand by our statement that The inclusion of genetic data combined with exposure data may better define which individuals in this cohort are at a particularly high risk of development of CBD and/or sensitization and may account for the absence of typical exposure–response seen with other environmental or occupational toxins. It is also important to note that both peak exposure and the different chemical and physical forms may be important factors in the risk of development of CBD but are not part of the current OSHA standard (OSHA 2005). Finally, Kolanz states that “Rosenman et al. (2005) made no recommendations regarding how to protect beryllium workers.” Clearly, however, our call to lower the allowable standard is a recommendation we put forth to protect beryllium workers. Despite the limitations of deriving historical exposure estimates, our corrected data continue to point to the inadequacy of the current OSHA standard to protect workers from developing chronic beryllium disease.

Exposure Assessment for a Study of Workers Exposed to Acrylonitrile. II. A Computerized Exposure Assessment Program

Abstract The validity of exposure assessment in retrospective epidemiologic studies has often been questioned, in part because systematic methods have not been developed to estimate historical exposure levels when insufficient monitoring results are available. In addition, documentation as to how the exposure estimates are derived is often lacking. A previously published report described a data management system, called Job Exposure Profiles, that organized and maintained job-related information available on each job in a mortality study of workers exposed to acrylonitrile. This database, and a second one containing almost 19,000 acrylonitrile monitoring results with accompanying documentation (job, department, date, type of sample, etc.), were linked to a computerized, interactive exposure assessment program (EAP) to allow the user to develop historical exposure estimates. The EAP is the subject of this report. In this program, monitoring results were sorted into various subfiles based on their quantity ...

Estimation of Cumulative Exposures to Naphtha at an Automobile Fuel-Injector Manufacturing Plant

As part of an epidemiologic study of neuropsychological and renal effects of occupational exposure to organic solvents, estimates of cumulative exposure to naphtha were derived for workers at an automobile fuel-injector manufacturing plant. The approach to exposure estimation was relatively unusual in three respects: (1) a marked association between indoor naphtha air concentration and outdoor temperature was modeled and applied to detailed historical temperature data to calculate cumulative exposure estimates; (2) the large number of investigator-generated air samples allowed the use of analyses of variance to compare alternative job-grouping schemes; and (3) the young age of the plant and few process changes allowed for historical exposure estimates with a high degree of confidence. The derived estimates of cumulative exposure appear to offer a firm basis for epidemiologic analyses of exposure-health outcome relationships.

ESTIMATION OF CUMULATIVE EXPOSURES TO NAPHTHA AT AN AUTOMOBILE FUEL-INJECTOR MANUFACTURING PLANT

As part of an epidemiologic study of neuropsychological and renal effects of occupational exposure to organic solvents, estimates of cumulative exposure to naphtha were derived for workers at an automobile fuel-injector manufacturing plant. The approach to exposure estimation was relatively unusual in three respects: (1) a marked association between indoor naphtha air concentration and outdoor temperature was modeled and applied to detailed historical temperature data to calculate cumulative exposure estimates; (2) the large number of investigator-generated air samples allowed the use of analyses of variance to compare alternative job-grouping schemes; and (3) the young age of the plant and few process changes allowed for historical exposure estimates with a high degree of confidence. The derived estimates of cumulative exposure appear to offer a firm basis for epidemiologic analyses of exposure-health outcome relationships.

Formaldehyde Levels in Seven Industries

Abstract Historical exposure estimates to formaldehyde were made in a recent retrospective cohort mortality study on workers exposed to formaldehyde in ten different plants. To supplement the historical information, personal air monitoring was conducted in each of the plants using the DuPont Pro-Tek[rgrave] badge. Three full-shift samples were taken in the summer and three in the winter. Some of the levels reported are unexpectedly high, possibly resulting from off-gassing of formaldehyde from the formaldehyde-containing dust, and may not reflect actual ambient air concentrations. The geometric means of the sampling results for formaldehyde in two manufacturers of formaldehyde ranged for the two seasons from 0.03 to 1.88 ppm and from 0.49 to 0.81 ppm. In the companies manufacturing formaldehyde resins, geometric seasonal means ranged from 0.11 to 30.45 ppm. Workers in the plants producing formaldehyde molding compounds were exposed to levels which were generally higher than those in resin manufacturing (0.04–60.77 ppm). Employees in the two plants producing molded plastic parts had seasonal mean exposures from none detected to 26.49 ppm. Mean concentrations for the two different seasons in the plant manufacturing decorative laminates were generally below 0.60 ppm, with only two jobs having mean exposures to formaldehyde greater than this level. In the plant manufacturing plywood paneling, mean exposures were below 0.40 ppm for all but one job. The majority of the jobs in the two plants which manufactured photographic film had mean exposures below 0.50 ppm. Although the results cited in this study may not reflect actual air levels, they may indicate that a significant source of formaldehyde exposure may occur from resin and molding compound dust.

Mortality Among Industrial Workers Exposed to Formaldehyde

A historical cohort study evaluated the mortality experience of 26,561 workers employed in 10 formaldehyde-producing or -using facilities. Approximately 600,000 person-years of follow-up accrued as workers were followed to January 1, 1980. Estimates of historical exposure to formaldehyde by job were developed by project industrial hygienists using monitoring data available from participating plants, comments from long-term workers, and comprehensive monitoring data specifically collected for this study. Mortality from all causes combined was about as expected [standardized mortality ratio (SMR) = 96] based on mortality rates of the general U.S. population. Significantly fewer deaths occurred from infective and parasitic diseases (SMR = 51) and from accidents (SMR = 72) than expected. Cancer overall was not related to formaldehyde exposure. Workers exposed to formaldehyde had slight excesses for Hodgkin's disease and cancers of the lung and prostate gland, but these excesses were not consistently related to duration of or average, cumulative, or peak formaldehyde exposure levels. Recent animal studies found nasal cancer among rats exposed to formaldehyde, but no excess of this tumor occurred in this study. Mortality from brain cancer and leukemia among these industrial workers was not excessive in contrast to reported excesses among professional groups (e.g., anatomists, embalmers, and pathologists) with exposure to formaldehyde. Although there was a deficit for cancer of the buccal cavity and pharynx, mortality from certain subsites, i.e., the nasopharynx and oropharynx, was elevated. These subsites did not, however, show a consistently rising risk with level of exposure. These data provide little evidence that mortality from cancer is associated with formaldehyde exposure at levels experienced by workers in this study.