Mental Health Disorders among Thai Farmers: Occupational and Non-Occupational Stressors.

This cross-sectional study aimed to identify occupational and non-occupational factors that impact levels of stress, depression, and anxiety among farmers located in the northern part of Thailand, including the potential psychological impacts of pesticide use. The participants (N=270) were interviewed with a survey adopted and modified from peer-reviewed articles and questionnaires. The survey consists of four parts, including demographic information and pesticide exposure; perceived farm stressors employing Farm Stressor Survey (FSS); mental health disorder utilizing Srithanya Stress Scale (ST5), Nine-Questions Depression- Rating Scale (9Q), and Depression Anxiety Stress Scale 21 (DASS21); in addition to COVID-related stress utilizing COVID Stress Scale (CSS). The participants were categorized into two groups i.e., Spray and No Spray based on their self-reported occupational use of pesticide spraying within the past year. No significant associations were observed between occupational pesticide exposures and mental health disorder scores. Being female, having a second job besides a farmer, having applied pesticides for greater than 20 years, and having a higher farm stressor perception showed a significant positive association with self-reported mental health disorders; while having a good agricultural practice and PPE use showed a significant negative association with those outcomes. This pilot study scrutinized expanded sources of stress in farm work and provided information for the development of more effective mental disorder intervention programs for Thai farmers.

Deployment to Military Bases With Open Burn Pits and Respiratory and Cardiovascular Disease.

Importance: Many veterans who served in Afghanistan and Iraq during Operations Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) were deployed to military bases with open burn pits and exposed to their emissions, with limited understanding of the long-term health consequences. Objective: To determine the association between deployment to military bases where open burn pits were used for waste disposal and the subsequent risk of developing respiratory and cardiovascular diseases. Design, Setting, and Participants: This retrospective observational cohort study used Veterans Health Administration medical records and declassified deployment records from the Department of Defense to assess Army and Air Force veterans who were deployed between 2001 and 2011 and subsequently received health care from the Veterans Health Administration, with follow-up through December 2020. Data were analyzed from January 2023 through February 2024. Exposure: Duration of deployment to military bases with open burn pits. Main Outcomes and Measures: Diagnosis of asthma, chronic obstructive pulmonary disease, interstitial lung disease, hypertension, myocardial infarction, congestive heart failure, ischemic stroke, and hemorrhagic stroke. Results: The study population included 459 381 OEF and OIF veterans (mean [SD] age, 31.6 [8.7] years; 399 754 [87.0%] male). Median (IQR) follow-up from end of deployment was 10.9 (9.4-12.7) years. For every 100 days of deployment to bases with burn pits, veterans experienced increased adjusted odds for asthma (adjusted odds ratio [aOR], 1.01; 95% CI, 1.01-1.02), chronic obstructive pulmonary disease (aOR, 1.04; 95% CI, 1.02-1.07), hypertension (aOR, 1.02; 95% CI, 1.02-1.03), and ischemic stroke (aOR, 1.06; 95% CI, 0.97-1.14). Odds of interstitial lung disease, myocardial infarction, congestive heart failure, or hemorrhagic stroke were not increased. Results based on tertiles of duration of burn pit exposures were consistent with those from the continuous exposure measures. Conclusions and Relevance: In this cohort study, prolonged deployment to military bases with open burn pits was associated with increased risk of developing asthma, COPD, and hypertension. The results also point to a possible increased risk in ischemic stroke. The novel ability to use integrated data on deployment and health outcomes provides a model for additional studies of the health impact of environmental exposures during military service.

Air, Dermal, and Urinary Metabolite Levels of Backpack and Tractor Sprayers Using the Herbicide Acetochlor in Thailand.

Acetochlor is a chloroacetanilide selective pre-emergent herbicide used for controlling grass and broadleaf weeds in crops. This study compared the acetochlor exposures of backpack and tractor sprayers and assessed whether dermal or air exposures were more important contributors to the overall body burden as measured by urinary metabolites. Sixty sugarcane farmers in Nakhonsawan province, Thailand participated in the study, and breathing zone air and dermal patch samples were collected during spraying. Urine samples were collected before spraying, at the end of the spraying task, and on the day after spraying. For backpack and tractor sprayers, there was no significant difference in their breathing zone air concentrations, total body dermal samples, or urinary 2-methy-6-methyaniline (EMA) concentrations on the day after spraying. In addition, although most backpack and tractor sprayers wore long pants and long sleeve shirts, they were still exposed to acetochlor, as evidenced by a significant increase in the urinary EMA from before spraying (GM = 11.5 µg/g creatinine) to after spraying (GM = 88.5 µg/g creatinine) to the next day (GM = 111.0 µg/g creatinine). Breathing zone air samples were significantly correlated with those of total body dermal patch samples and with urinary EMA concentrations after spraying. This suggests that both air and dermal exposure contribute to urinary EMA levels.

Burn Pit Exposure Assessment to Support a Cohort Study of US Veterans of the Wars in Iraq and Afghanistan.

OBJECTIVE: For a cohort study of veterans' health conditions, we conducted an exposure assessment for 109 bases in Iraq and Afghanistan and 17 outside transit site bases. METHODS: The Department of Defense records were used to determine burn pit usage and waste disposal methods for each base in each year during the period of 2001 to 2014. RESULTS: In the final cohort of 475,326 veterans, who had more than 80% of their deployment time characterized by our exposure matrix, only 14.5% were found to have no burn pit exposure. The 2009 Department of Defense regulations on burn pits did produce changes in waste segregation, as well as adding incineration and local disposal of waste. CONCLUSION: Most Iraq and Afghanistan veterans were stationed on bases that had burn pits, although the contents disposed of in the burn pits changed over time.

Disruption of the Diurnal Cortisol Hormone Pattern by Pesticide Use in a Longitudinal Study of Farmers in Thailand.

Alteration of the hypothalamic-pituitary-adrenal (HPA) axis hormones has been associated with a range of chronic metabolic and cardiovascular health conditions. This study evaluated whether type of farming (organic versus conventional) or the number of self-reported days of spraying pesticides in the past 8 months was associated with diurnal cortisol levels. Salivary cortisol levels were measured four times a day (waking, 30 min after waking, 6 h after waking and bedtime) longitudinally, 8 months apart during three rounds of data collection. Pesticide using (conventional) and organic farmers were recruited to participate. Pesticide use in the previous 8 months was determined as the number of spray days for each type of pesticide used (herbicide, insecticide, fungicide) from self-reported questionnaires. Estimates of cortisol levels at four time points, the cortisol awakening response (CAR), and the diurnal cortisol slope (DCS) were estimated with a longitudinal mixed model that accounted for the non-linearity of cortisol levels across the day. Conventional farmers had significantly lower cortisol levels at waking than organic farmers (3.39 versus 3.86 ng ml-1), 30 min after waking (5.87 versus 6.96 ng ml-1), 6 h after waking (1.62 versus 1.88 ng ml-1), and lower diurnal cortisol slope (-2.26 versus -2.51 ng ml-1). Farmers who frequently applied herbicides (90th percentile of the number of spray days in the past 8 months) had significantly lower waking, 30 min after waking, 6 h after waking, bedtime and diurnal cortisol slopes compared with those with no spray days of herbicide in the past 8 months (organic and some of the conventional farmers). Those who frequently applied insecticides in the past 8 months had significantly lower bedtime levels and diurnal cortisol slopes, compared with those with no spray days of insecticide in the past 8 months. There were no significant differences in cortisol hormones between those who frequently applied fungicides and those who did not spray fungicides. Repeated pesticide use appears to be disrupting the HPA axis and depressing the normal diurnal cortisol rhythm among conventional Thai farmers.

Hearing Loss in Agricultural Workers Exposed to Pesticides and Noise.

Agricultural workers who have concurrent exposure to pesticides and noise are at increased risk of hearing loss. We recruited 163 Thai conventional and 172 organic farmers to answer our questionnaires about personal demographics, agricultural activities, and pesticide and agricultural machinery use. This information was used to calculate the years of conventional (pesticide use) farming and the years of agricultural noise exposure, and to estimate semiquantitative metrics for pesticide exposure (cumulative intensity score-years) and cumulative noise exposure (dB(A)-years) for each conventional farmer. All participants underwent pure tone audiometric testing. The mean hearing threshold in the low-frequency band (0.5-2 kHz) and high-frequency band (3-6 kHz) were used for analysis. Years involved in conventional farming and years using agricultural machinery were associated with an increase in the average hearing threshold for the high-frequency band after controlling for age, ever exposed to industrial noise and cigarette smoking. The highest category of cumulative insecticide exposure (score-years), cumulative organophosphates exposure (score-years) and cumulative noise exposure (dB(A)-years) were also associated with an increased high-frequency band hearing threshold among conventional farmers. Results from the full cohort and the subcohort of conventional farmers support each other and the hypothesis that pesticide and noise have an additive effect on hearing, since no model interactions were significant.

Characterization of Occupational Exposures to Respirable Silica and Dust in Demolition, Crushing, and Chipping Activities.

Objectives: Exposures to respirable crystalline silica (RCS) and respirable dust (RD) were investigated during demolition, crushing, and chipping at several Massachusetts construction sites. Methods: Personal breathing zone samples (n = 51) were collected on operating engineers working at demolition and crushing sites, laborers performing miscellaneous tasks at demolition sites, crushing machine tenders at crushing sites, and chipping workers at substructure bridge repair sites. Area samples (n = 33) were collected at the perimeter of demolition and crushing sites to assess potential bystanders' exposures. Exposures 'with' and 'without' the use of dust suppression methods were compared when possible. RD samples were analyzed for crystalline silica content with Fourier Transform Infrared Spectrophotometry (FT-IR) according to the National Institute for Occupational Safety and Health (NIOSH) Method 7602. Statistical analyses of the exposure data were performed in SAS version 9.4. Results: Chipping workers had the highest exposure levels [the geometric mean (GM) time-weighted average (TWA) for RCS was 527 µg/m3 and the GM for RD was 4750 µg/m3]. The next highest exposures were among crushing machine tenders (RCS GM of 93.3 µg/m3 and RD GM of 737.6 µg/m3), while laborers and operating engineers had the lowest exposures (RCS GM of 17.0 and 6.2 µg/m3, respectively). Personal 8-h TWA RCS exposures were higher than the new OSHA permissible exposure limit (PEL) of 50 µg/m3 for 80% of samples collected on chipping workers (n = 31) and 50% of samples collected on crushing machine tenders (n = 8). Operating engineers (n = 9) and laborers (n = 3) had RCS exposures lower than OSHA PEL. The highest concentrations measured would have exceeded the PEL within 15 min chipping and within 2 h of crushing with no further exposure. Chipping workers' RCS exposures were higher than OSHA PEL even when they were adjusted to account for the assigned protection factor of the half-face N95 cartridge respirators used during chipping. Exposures of crushing tenders were reduced to levels under the OSHA PEL when a water spraying system in crushing machines was utilized, but not when a water cannon machine was used. Area samples at demolition and crushing sites indicate overall lower exposures than the PEL, however, bystander workers at crushing sites could be exposed to higher levels compared to demolition sites. Real-time dust monitoring during demolition indicate very high short-term peak exposures. Conclusions: Controlling or reducing crystalline silica exposures to levels under the new OSHA PEL of 50 µg/m3 remains challenging for chipping workers and crushing machine tenders. Even with the use of dust suppression controls, respiratory protection may be required for various tasks.

Retrospective Assessment of Occupational Exposures for the GENEVA Study of ALS among Military Veterans.

OBJECTIVE: This paper describes the retrospective exposure assessment conducted to assess occupational exposures for the Genes and Environmental Exposures in Veterans (GENEVA) study, a case-control study investigating the joint contribution of genetics and environmental exposures to the risk of amyotrophic lateral sclerosis (ALS) among military veterans. METHODS: Occupational histories for 1597 study participants collected as part of the GENEVA study were the basis for this retrospective exposure assessment. The data set included 15528 jobs held from 1924 to 2010, representing 4539 unique industry and occupation (I&O) combinations. Three industrial hygiene experts were recruited to independently rate occupational exposures to specific agents previously associated with an increased risk of ALS. Utilizing information on industry, job title, tasks performed, and materials used for each job held, raters assigned exposures associated with each I&O for the 'current time' defined as the period after 1995 (post-1995). The exposure assessment targeted agents identified as potential occupational risk factors for ALS. Experts rated semi-quantitatively exposure intensity in five exposure categories (0-4) for Group A agents (lead, formaldehyde, hydrocarbon solvents, and chlorinated solvents) and qualitatively as yes/no (1/0) exposed for Group B agents (mercury, selenium, arsenic, polychlorinated biphenyls, electromagnetic field, pesticides, and viral agents). Confidence scores (0-3) were reported for every I&O rated based on raters' experience with that industry and/or job. Each I&O was assigned an average exposure score of the raters and an alternative exposure rating was developed for each I&O by excluding low confidence (<2) scores before averaging. Exposure reconstruction for jobs held pre-1995 was done by comparing exposure data extracted from the OSHA Chemical Exposure and Health Database (CEHD) during pre-1995 and post-1995. For agents with limited exposure data in the CEHD, pre-1995 exposures were determined based on raters' judgment. RESULTS: The proportion of I&O combinations determined to be 'exposed' ranged from 0.1 to 26% across different agents, with the highest values corresponding to hydrocarbon solvents and the lowest to selenium. Industries with the highest proportion of exposed records include manufacturing, utilities, healthcare, and military with non-combat jobs. Analyses for raters' reliability showed the best agreement between the raters when rating exposure to viral agents (kappa = 0.67), hydrocarbon solvents (kappa = 0.53), and lead (kappa = 0.50). The proportion of 'exposed' I&O combinations increased for hydrocarbon solvents, chlorinated solvents, and pesticides when exposure ratings were adjusted by raters' confidence. Compared to post-1995, exposures in the earlier period (pre-1995) were deemed higher or the same for most of the agents and lower for formaldehyde and electromagnetic field exposures. CONCLUSIONS: Our results indicate that using raters' confidence assessment in determining exposure scores increases both the proportion of I&O combinations regarded as exposed and the intensity scores, suggesting raters tend to be conservative in their assessment when they lack detailed knowledge of an industry or job.

Exposures to nanoparticles and fibers during injection molding and recycling of carbon nanotube reinforced polycarbonate composites.

In this study, the characteristics of airborne particles generated during injection molding and grinding processes of carbon nanotube reinforced polycarbonate composites (CNT-PC) were investigated. Particle number concentration, size distribution, and morphology of particles emitted from the processes were determined using real-time particle sizers and transmission electron microscopy. The air samples near the operator's breathing zone were collected on filters and analyzed using scanning electron microscope for particle morphology and respirable fiber count. Processing and grinding during recycling of CNT-PC released airborne nanoparticles (NPs) with a geometric mean (GM) particle concentration from 4.7 × 103 to 1.7 × 106 particles/cm3. The ratios of the GM particle concentration measured during the injection molding process with exhaust ventilation relative to background were up to 1.3 (loading), 1.9 (melting), and 1.4 (molding), and 101.4 for grinding process without exhaust ventilation, suggesting substantial NP exposures during these processes. The estimated mass concentration was in the range of 1.6-95.2 µg/m3. Diverse particle morphologies, including NPs, NP agglomerates, particles with embedded or protruding CNTs and fibers, were observed. No free CNTs were found during any of the investigated processes. The breathing zone respirable fiber concentration during the grinding process ranged from non-detectable to 0.13 fiber/cm3. No evidence was found that the emissions were affected by the number of recycling cycles. Institution of exposure controls is recommended during these processes to limit exposures to airborne NPs and CNT-containing fibers.

Characterization of Potential Exposures to Nanoparticles and Fibers during Manufacturing and Recycling of Carbon Nanotube Reinforced Polypropylene Composites.

Carbon nanotube (CNT) polymer composites are widely used as raw materials in multiple industries because of their excellent properties. This expansion, however, is accompanied by realistic concerns over potential release of CNTs and associated nanoparticles during the manufacturing, recycling, use, and disposal of CNT composite products. Such data continue to be limited, especially with regards to post-processing of CNT-enabled products, recycling and handling of nanowaste, and end-of-life disposal. This study investigated for the first time airborne nanoparticle and fibers exposures during injection molding and recycling of CNT polypropylene composites (CNT-PP) relative to that of PP. Exposure characterization focused on source emissions during loading, melting, molding, grinding, and recycling of scrap material over 20 cycles and included real-time characterization of total particle number concentration and size distribution, nanoparticle and fiber morphology, and fiber concentrations near the operator. Total airborne nanoparticle concentration emitted during loading, melting, molding, and grinding of CNT-PP had geometric mean ranging from 1.2 × 10(3) to 4.3 × 10(5) particles cm(-3), with the highest exposures being up to 2.9 and 300.7 times above the background for injection molding and grinding, respectively. Most of these emissions were similar to PP synthesis. Melting and molding of CNT-PP and PP produced exclusively nanoparticles. Grinding of CNT-PP but not PP generated larger particles with encapsulated CNTs, particles with CNT extrusions, and respirable fiber (up to 0.2 fibers cm(-3)). No free CNTs were found in any of the processes. The number of recycling runs had no significant impact on exposures. Further research into the chemical composition of the emitted nanoparticles is warranted. In the meanwhile, exposure controls should be instituted during processing and recycling of CNT-PP.

Evaluation of leakage from fume hoods using tracer gas, tracer nanoparticles and nanopowder handling test methodologies.

The most commonly reported control used to minimize workplace exposures to nanomaterials is the chemical fume hood. Studies have shown, however, that significant releases of nanoparticles can occur when materials are handled inside fume hoods. This study evaluated the performance of a new commercially available nano fume hood using three different test protocols. Tracer gas, tracer nanoparticle, and nanopowder handling protocols were used to evaluate the hood. A static test procedure using tracer gas (sulfur hexafluoride) and nanoparticles as well as an active test using an operator handling nanoalumina were conducted. A commercially available particle generator was used to produce sodium chloride tracer nanoparticles. Containment effectiveness was evaluated by sampling both in the breathing zone (BZ) of a mannequin and operator as well as across the hood opening. These containment tests were conducted across a range of hood face velocities (60, 80, and 100 ft/min) and with the room ventilation system turned off and on. For the tracer gas and tracer nanoparticle tests, leakage was much more prominent on the left side of the hood (closest to the room supply air diffuser) although some leakage was noted on the right side and in the BZ sample locations. During the tracer gas and tracer nanoparticle tests, leakage was primarily noted when the room air conditioner was on for both the low and medium hood exhaust airflows. When the room air conditioner was turned off, the static tracer gas tests showed good containment across most test conditions. The tracer gas and nanoparticle test results were well correlated showing hood leakage under the same conditions and at the same sample locations. The impact of a room air conditioner was demonstrated with containment being adversely impacted during the use of room air ventilation. The tracer nanoparticle approach is a simple method requiring minimal setup and instrumentation. However, the method requires the reduction in background concentrations to allow for increased sensitivity.

Retrospective assessment of exposure to chemicals for a microelectronics and business machine manufacturing facility.

A retrospective exposure assessment was performed for use in a health outcomes study of a facility manufacturing circuit boards, business machines, and other equipment during the years 1969-2002. A matrix was developed identifying chemical use by department-year based on company-provided information. Use of six chemical agents (fiberglass, lead, methylene chloride, methyl chloroform, perchloroethylene, and trichloroethylene) and six chemical classes (acid-base, aromatic hydrocarbons, chlorinated hydrocarbons, other hydrocarbons, chlorofluorocarbons, and metals), and general (including unspecified) chemicals was identified. The matrix also contained an assignment for each department-year categorizing the potential for use of chemicals as negligible, intermittent/incidental, or routine. These department-based exposure matrix data were combined with work history data to provide duration of potential chemical use for workers. Negligible, intermittent/incidental or routine extent-of-chemical-use categories comprised 42.6%, 39.4%, and 17.9%, respectively, of total person-years of employment. Cumulative exposure scores were also developed, representing a relative measure of the cumulative extent of potential exposure to the six chemical agents, six chemical classes, and general (including unspecified) chemicals. Additionally, the study period was divided into manufacturing eras showing trends in chemical use, and showing that process use of trichloroethylene and methylene chloride ended in the mid-1980s and the mid-1990s, respectively. This approach may be useful in other assessments addressing a variety of chemicals, and with data constraints common to retrospective chemical exposure studies.

Respiratory effects among rubberwood furniture factory workers in Thailand.

Respiratory symptoms and pulmonary function were examined among 89 rubberwood furniture factory workers. Acute and chronic irritant symptoms were assessed, lung function was measured both pre- and post-shift and personal inhalable dust exposure determined. The only symptoms with a significant increase among high dust level-exposed workers (>1 mg/m(3)) were those related to nasal irritation. High dust level-exposed workers had a significant cross-shift decrease in forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) compared with low dust level-exposed workers and increases in inhalable dust concentration levels (mg/m(3)) were significantly associated with decreases in the peak expiratory flow (PEF) across the work shift. For percent predicted pulmonary function levels, a significant decrement in PEF was found for high versus low rubberwood dust level-exposed workers, after controlling for confounders. These findings suggest the need for an occupational standard for rubberwood dust in Thailand.

Retrospective exposure assessment of perfluorooctanoic acid serum concentrations at a fluoropolymer manufacturing plant.

Perfluorooctanoic acid (PFOA) is a suspect human carcinogen, causes neonatal loss, liver enlargement, and a variety of tumors in rodents, and has been associated with increased cholesterol levels in humans. Mortality analyses of worker cohorts have not been conclusive or consistent. As part of a series of epidemiologic studies of workers in a West Virginia plant that manufactures fluoropolymers, estimates of serum PFOA for the worker cohort were developed for the period of 1950-2004. An existing database of 2125 worker biomarker measurements of serum PFOA was used to model retrospective exposures. Historical PFOA serum levels for eight job category/job group combinations were modeled using linear mixed models to account for repeated measures, along with exposure determinants such as cumulative years worked in potentially exposed jobs, the amount of C8 used or emitted by the plant over time, as well as a four-knot restricted cubic spline function to reflect the influence of process changes over calendar time on exposure. The modeled biomarker levels matched well with measured levels, including those collected independently as part of a community study of PFOA levels (Spearman correlations of 0.8 for internal data comparisons and 0.6 for external data comparisons). These annualized PFOA serum estimates will be used in a series of morbidity and mortality studies of this worker cohort.

World Trade Center disaster: assessment of responder occupations, work locations, and job tasks.

BACKGROUND: To date there have been no comprehensive reports of the work performedby 9/11 World Trade Center responders. METHODS: 18,969 responders enrolled in the WTC Medical Monitoring and Treatment Program were used to describe workers' pre-9/11 occupations, WTC work activities and locations from September 11, 2001 to June 2002. RESULTS: The most common pre-9/11 occupation was protective services (47%); other common occupations included construction, telecommunications, transportation, and support services workers. 14% served as volunteers. Almost one-half began work on 9/11 and >80% reported working on or adjacent to the ''pile'' at Ground Zero. Initially,the most common activity was search and rescue but subsequently, the activities of most responders related to their pre-9/11 occupations. Other major activities included security; personnel support; buildings and grounds cleaning; and telecommunications repair. CONCLUSIONS: The spatial, temporal, occupational, and task-related taxonomy reported here will aid the development of a job-exposure matrix, assist in assessment of disease risk, and improve planning and training for responders in future urban disasters.

Understanding workplace processes and factors that influence exposures to engineered nanomaterials.

There is a critical need to understand the factors that influence engineered nanomaterial (ENM) exposures in the workplace. Such an understanding would aid in: identifying and prioritizing control measures; targeting future exposure measurements; and predicting worker exposures for work scenarios. This information could also be used in epidemiological studies. We propose a multitiered model in which information on exposure factors can be obtained at the macrolevel (examining differences in exposures between different ENM sectors or product types); the midlevel (examining differences in exposures between workplaces within the same ENM sector or product type); and the microlevel (examining differences in exposure between tasks or between ENM types during the same task). Further, within the microlevel, potential exposure factors are defined by a source-receptor model. We recommend that auxiliary data be collected systematically, along with exposure measurements, to enable analysis of exposure factors as well as the pooling of data across studies.

Agreement between task-based estimates of the full-shift noise exposure and the full-shift noise dosimetry.

Noise assessments have been conducted using full-shift dosimetry and short-term task-based measurements. Advantages of the task-based method include the opportunity to directly identify high-noise exposure tasks and to target control measures, as well as obtain estimates of task-based full-shift exposures; however, there is little empirical evidence comparing the two methods. National Institute for Occupational Safety and Health assessed noise exposures at three industrial facilities using dosimetry and task-based methods with the objective of comparing the two strategies and assessing the degree of agreement and causes of disagreement. Eight indices of task-based full-shift exposures were created from task-based sampling using three methods to assess time-at-task (direct observation by industrial hygienist, end-of-shift worker estimates and supervisor estimates) and three methods to assign noise levels to tasks [direct measurement, arithmetic mean (AM) and geometric mean (GM)]. We assessed aspects of agreement (precision, bias and absolute agreement) using Bland-Altman plots and concordance correlation coefficient (CCC). Overall, the task-based methods worked fairly well, with mean biases less than +/-2.8 dBA and precision ranges of 3.3-4.4 dBA. By all measures, task-based full-shift estimates based on supervisor assessment of time-at-task agreed most poorly with the dosimetry data. The task-based full-shift estimates based on worker estimates of time-at-task generally agreed as well as those based on direct observation. For task noise level, task-based full-shift estimates based on directly measured task agreed the best with dosimetry data, while agreement for task-based indices based on task AM or GM was variable. Overall, the task-based full-shift estimates based on direct observation task and direct measured task noise level achieved the best agreement with the dosimetry data (CCC 0.84) with 95% of their differences being within 7.4 dBA and 56% of the differences <3 dBA. For this index, a high degree of accuracy was observed (accuracy coefficient = 0.96) with major cause of disagreement arising from a lack of precision (precision coefficient = 0.88). When the measurements were classified by job characteristics, significant improvements in the degree of agreement were observed in the low job mobility, low job complexity and low job variability categories. Our data suggest that a high degree of absolute agreement can be achieved between the task-based and dosimetry-based estimates of full-shift exposures. The task-based approach that uses worker reports combined with task AM or GM levels is similar to the more time-intensive direct observation method to estimate full-shift exposures.

Skin and surface lead contamination, hygiene programs, and work practices of bridge surface preparation and painting contractors.

A 2005 regulatory review of the lead in construction standard by the Occupational Safety and Health Administration (OSHA) noted that alternative pathways of exposure can be as significant as inhalation exposure and that noncompliance with the standard pertaining to hygiene facilities and practices was the second most commonly violated section of the standard. Noncompliance with provisions of the standard and unhealthy work and hygiene practices likely increase the likelihood of take-home lead via contaminated clothing, automobiles, and skin, thus contributing to elevated blood lead levels (BLL) among construction workers and their family members. We performed a cross-sectional study of bridge painters working for small contractors in Massachusetts to investigate causes of persistent elevated BLLs and to assess lead exposures. Thirteen work sites were evaluated for a 2-week period during which surface and skin wipe samples were collected and qualitative information was obtained on personal hygiene practices, decontamination and hand wash facilities, and respiratory protection programs. Results showed lead contamination on workers' skin, respirators, personal automobiles, and the decontamination unit, indicating a significant potential for take-home lead exposure. Overall, the geometric mean (GM) skin lead levels ranged from 373 microg on workers' faces at end of shift to 814 microg on hands at break time. The overall GM lead level inside respirators was 143 microg before work and 286 microg after work. Lead contamination was also present inside workers' personal vehicles as well as on surfaces inside the clean side of the decontamination unit. Review of the respiratory protection programs, work site decontamination and hand wash facilities, and personal hygiene practices indicated that these factors had significant impact on skin and surface contamination levels and identified significant opportunities for improving work site facilities and personal practices. Elevated lead exposure and BLL can be minimized by strict adherence to the OSHA provisions for functioning decontamination and hygiene facilities and healthy personal hygiene practices.

Skin exposure to aliphatic polyisocyanates in the auto body repair and refinishing industry: III. A personal exposure algorithm.

OBJECTIVES: Isocyanate skin exposure may play an important role in sensitization and the development of isocyanate asthma, but such exposures are frequently intermittent and difficult to assess. Exposure metrics are needed to better estimate isocyanate skin exposures. The goal of this study was to develop a semiquantitative algorithm to estimate personal skin exposures in auto body shop workers using task-based skin exposure data and daily work diaries. The relationship between skin and respiratory exposure metrics was also evaluated. METHODS: The development and results of respiratory exposure metrics were previously reported. Using the task-based data obtained with a colorimetric skin exposure indicator and a daily work diary, we developed a skin exposure algorithm to estimate a skin exposure index (SEI) for each worker. This algorithm considered the type of personal protective equipment (PPE) used, the percentage of skin area covered by PPE and skin exposures without and underneath the PPE. The SEI was summed across the day (daily SEI) and survey week (weekly average SEI) for each worker, compared among the job title categories and also compared with the respiratory exposure metrics. RESULTS: A total of 893 person-days was calculated for 232 workers (49 painters, 118 technicians and 65 office workers) from 33 auto body shops. The median (10th-90th percentile, maximum) daily SEI was 0 (0-0, 1.0), 0 (0-1.9, 4.8) and 1.6 (0-3.5, 6.1) and weekly average SEI was 0 (0-0.0, 0.7), 0.3 (0-1.6, 4.2) and 1.9 (0.4-3.0, 3.6) for office workers, technicians and painters, respectively, which were significantly different (P < 0.0001). The median (10th-90th percentile, maximum) daily SEI was 0 (0-2.4, 6.1) and weekly average SEI was 0.2 (0-2.3, 4.2) for all workers. A relatively weak positive Spearman correlation was found between daily SEI and time-weighted average (TWA) respiratory exposure metrics (microg NCO m(-3)) (r = 0.380, n = 893, P < 0.0001) and between weekly SEI and TWA respiratory exposure metrics (r = 0.482, n = 232, P < 0.0001). CONCLUSIONS: The skin exposure algorithm developed in this study provides task-based personal daily and weekly average skin exposure indices that are adjusted for the use of PPE. These skin exposure indices can be used to assess isocyanate exposure-response relationships.