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PubMed1991

Environmental versus analytical variability in exposure measurements.

Measurements of 8-hr time-weighted average (TWA) exposures are subject to environmental variability and collection and analytical error. Environmental variability can be represented by the geometric standard deviation (GSD) of the lognormally distributed 8-hr TWAs; analytical variability can be represented by the coefficient of variation (CV) of the normally distributed collection and analytical errors. A mathematical expression is derived for the variance of the measured 8-hr TWAs as a function of the GSD of the true daily average exposures and the total CV of the industrial hygiene method used in monitoring. For typical values of the GSD and CV, environmental variability is far more important than analytical variability in determining the variance of the measured 8-hr TWAs. A resulting policy implication is that the Occupational Safety and Health Administration inappropriately focuses on analytical variability when determining compliance with its permissible exposure limits.

Bias↗

PubMedDate not supplied

Task-based assessment of occupational vibration and noise exposures in forestry workers.

Forty-two noise exposures and 164 whole-body (WBV) and hand-arm (HAV) vibration exposures were collected from 43 forestry workers in six trades employed by two forestry companies. Data were collected on 10 days over 8 weeks during various felling, logging, and log handling operations. Up to 5 volunteers were monitored for noise and vibration daily using datalogging noise dosimeters, which provided daily time-weighted averages (TWAs) and 1-min averages; and a precision sound level meter equipped to measure human vibration, which provided triaxial HAV and WBV event-weighted averages (AEQS). Workers completed a short questionnaire throughout the workday detailing the timing and number of tasks performed and equipment used. Substantial overexposures to noise and vibration were seen; for example, 60% of Occupational Safety and Health Administration (OSHA) TWAs and 83% of National Institute for Occupational Safety and Health (NIOSH) noise TWAs exceeded 85 dBA, 33-53% of the axis-specific HAV AEQS exceeded the 8-hour American Conference of Governmental Industrial Hygienists' HAV threshold limit value, and 34% of all summary weighted WBV AEQS exceeded the Commission of the European Communities' 8-hour exposure limit. The mean for 99 WBV summary weighted AEQ was 3.53 +/- 7.12 m/sec2, whereas the mean for 65 HAV summary weighted AEQ was 5.45 +/- 5.25 m/sec2. The mean OSHA TWA was 86.1 +/- 6.2 dBA, whereas the mean NIOSH TWA was 90.2 +/- 5.1 dBA. The task and tool with the highest exposure levels were unbelling chokers on landings and chain saws (noise), log processing and frontend loaders (WBV), and notching stumps and chain saws (HAV). An internal validation substudy indicated excellent agreement between worker-reported and researcher-documented tasks and tools.

Adult↗

PubMedDate not supplied

Hepatotoxicity associated with overexposure to 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123).

1,1-Dichloro-2,2,2-trifluoroethane (HCFC-123) was evaluated as a substitute for trichlorofluoromethane (CFC-11), and it appeared that a permissible exposure limit of 50 ppm was justified. When HCFC-123 was introduced as a precision cleaning agent in a controlled operation, marked elevations in serum alanine transaminase and serum aspartase transaminase were noted in exposed workers. Sampling taken during start-up documented personal samples from 24-480 ppm (375 and 21 min, respectively) and area samples of 18-180 ppm (375 and 21 min, respectively). Personal and area samples collected after the liver abnormalities were identified ranged from 5-12 ppm. Exposure data were not available for the period when the abnormalities are suspected to have developed. Two models were developed to estimate exposure during the unmonitored period: (1) the entire plant as a homogenous box and (2) evaporation into smaller work zones. Modeling using the entire building estimated 8-hour time-weighted average (TWA) exposures of 10-35 ppm. Modeled estimates of work area and air exchange rates indicated that degreaser exposed workers could have experienced peak levels of 280-2,100 ppm (8-hour TWAs 252-1,630 ppm). Modeling of the work environment, estimated to be one-third of the volume of the entire open building, indicated peak exposures of 28-210 ppm (8-hour TWAs 25-163 ppm). These ranges estimate the minimum and maximum exposure levels. The best estimates, using 12 air changes per day, suggest peak levels around the degreaser of 635-2,100 ppm (8-hour TWA 499-1,630 ppm) and 63-207 ppm (8-hour TWAs 50-163 ppm) in the work area. These are the first estimates of exposure level associated with these hepatotoxic effects; all are significantly higher than personal and area samples collected for HCFC-123 after the liver abnormalities were identified.

Chemical and Drug Induced Liver Injury↗

PubMed2026

Quantitative trait loci mapping of gene expression and chromatin accessibility in primary fibroblasts reveals shared allelic effects between Latin American and European ancestries.

BACKGROUND: Quantitative Trait Locus (QTL) analysis of molecular data has identified genetic variants associated with traits such as gene expression, and colocalization of these functional QTL with GWAS risk loci has offered insights into the genetic basis of human disease. We employed gene expression (RNA-seq) and chromatin accessibility (ATAC-seq) obtained from human primary fibroblasts to investigate quantitative trait loci (QTLs) in cohorts ascertained for bipolar disorder of European (n = 150) and Latin American (n = 96) ancestries. RESULTS: Leveraging data from three countries of origin (The Netherlands, Colombia, Costa Rica) within our cohort, we characterized differences among individuals at the SNP, gene, and accessible-chromatin levels to compute ancestry-specific expression (e)QTLs and chromatin-accessibility (ca)QTLs. Across ancestries, we observed R2 ≥ 0.93 for eQTL effect sizes and R2 ≥ 0.95 for caQTLs, indicating a high degree of concordance. Integrating chromatin data with expression and genotype information enabled precise fine-mapping of eQTLs, yielding 203 genes with high-confidence (posterior probability > 90%) candidate regulatory pathways. In downstream analyses, transcriptome-wide (TWAS) and chromatin-wide (CWAS) association studies with brain- and skin-related GWAS identified 36 TWAS-significant genes and 77 CWAS-significant open chromatin regions. CONCLUSIONS: These findings underscore the shared genetic regulatory mechanisms across European and Latin American ancestries, while demonstrating that ancestry-specific reference panels enhance the accuracy of TWAS and CWAS in diverse populations. More broadly, this study highlights the value of paired multi-omic datasets from diverse cohorts for interpreting disease-associated genetic variation.

Humans↗

PubMed2026

A minimal three-arm oral regimen for healthspan: mechanistic alignment with transcriptomic signals from a large parental-lifespan GWAS.

A large genome-wide association study of parental lifespan was reported in 2019. A later transcriptome-wide association study (TWAS) based on those summary statistics identified a set of transcriptional programs associated with longer genetically predicted survival, including increased brain NAD + salvage, especially NMNAT2, reduced glucose-stimulated insulin secretion, a shift toward synaptic pruning with less broad plasticity, and a glial pattern characterized by relatively greater microglial and lower astrocytic signatures, with only weak pan-tissue senescence signals. Building on those directional findings, this short communication proposes a minimal three-arm oral regimen with unequal evidentiary weight: first, the Cheung Glutamatergic Regimen, consisting of low-dose dextromethorphan potentiated by a CYP2D6 inhibitor together with piracetam and L-glutamine, as an exploratory adjunct aimed at preserving residual functional connectivity; second, daily nicotinamide mononucleotide and N-acetylcysteine with pulsed senolytics for NAD + salvage and senescence modulation; and third, GLP-1 receptor agonism for metabolic reprogramming. The NAD+/senescence arm is the primary mechanistic anchor, GLP-1 receptor agonism provides secondary metabolic support, and the glutamatergic arm is exploratory. Each arm targets a separate node within the pruning-plasticity-metabolic triad. The regimen is fully oral, uses conservative dosing, and draws on prior therapeutic or human-exposure data, although the proposed combination has no established safety profile. Although direct combination data are lacking and the foundational TWAS remains a preprint, the components show plausible but uneven mechanistic alignment with the TWAS signals and may justify carefully designed, safety-focused pilot evaluation.

GLP-1↗

PubMed2026

FM-GPT: Bayesian fine mapping for phenome-wide transcriptome-wide association studies.

Transcriptome-wide association studies (TWAS) integrate genome wide association studies with expression quantitative trait locus reference panels to identify genes associated with traits of interest. However, linkage disequilibrium and correlated gene expression can induce spurious TWAS signals, motivating fine mapping methods to prioritize putatively causal genes within associated loci. The rapid growth of large-scale phenomic resources (e.g. electronic health records (EHRs)) has shifted genetic studies from single-trait analyses to phenome-wide investigations that jointly evaluate many closely related phenotypes. We introduce FM-GPT (Fine-mapping of causal Genes for Phenome-wide Transcriptome-wide association studies), a novel Bayesian fine mapping method for prioritizing causal genes across multiple correlated phenotypes with potentially mixed outcome types (e.g., binary, count or continuous) in phenome-wide TWAS. FM-GPT performs gene-guided dimension reduction of the phenotypes and reveals pleiotropic or phenotype-specific effects of the identified genes. In simulations, FM-GPT identified true causal genes more accurately than other fine mapping methods while controlling false positives. We applied FM-GPT to two applications using data from UK Biobank: a brain-wide genetic analysis of MRI data derived regional cortical thickness measures and a phenome-wide genetic analysis of clinical phenotypes derived from EHR data. FM-GPT greatly narrowed down the set size of putatively causal genes and identified: 1. genes with pleiotropic effects on regional cortical thickness across the cerebral cortex, including five genes BCAS3, LRRC37A, NOS2P3, ARL17B and UBB on chromosome 17 regulating neuronal morphology and cortical organization; and 2. genes that influence multiple medical conditions across the circulatory, metabolic, digestive, respiratory and genitourinary systems, revealing two major axes of variation among these conditions that point to a potential trade-off in gene regulation between immune and metabolic functions. These results highlight FM-GPT's power to disentangle complex gene-phenotype relationships in large-scale phenome-wide studies, uncovering shared biological mechanisms across diverse human traits and advancing translational and comorbidity research.

Bayesian fine mapping↗

PubMed2026

Genetic evidence links hypertension to accelerated brain aging.

Hypertension affects one-third of adults and is a major comorbidity of neurocognitive disorders. The causal relationship, shared genetic architecture, and upstream mechanisms linking hypertension to brain aging remain unclear. Hypertension GWAS datasets from MVP and FinnGen R12 were meta-analyzed as the exposure, and a European-ancestry brain age gap (BAG) GWAS derived from the UK Biobank and LIFE-Adult cohorts was used as the outcome. MR and GSMR assessed causality. LDSC, HDL, and S-LDSC estimated genetic correlation. Four TWAS methods (MAGMA, FUSION, JTI-PrediXcan, FOCUS) mapped associations to genes, followed by SMR for causal validation and PoPS for prioritization. GSMAP with spatial transcriptomics characterized regional and cell-type enrichment. Hypertension and brain aging were genetically correlated, and MR and GSMR analyses suggested a causal effect of hypertension on increased brain age gap. TWAS identified 15 shared Hypertension-BAG genes, 10 supported by SMR. PoPS prioritized TRIM47 as the core gene. Shared signals were enriched in meninges, fiber tracts, cortical layer 1, and CA1 stratum lacunosum/radiatum, with cell-type enrichment in meninges, smooth muscle cells, oligodendrocytes, and astrocyte subtypes. Hypertension is genetically correlated with, and shows evidence of a causal effect on, accelerated brain aging. TRIM47 is a core gene bridging hypertension and BAG. GSMAP-based spatial enrichment provides a hypothesis-generating framework for understanding vascular, meningeal, and myelin-related pathways linking hypertension to increased brain age gap.

Humans↗

PubMed2025

Multi-ancestry genome-wide and transcriptome-wide association analyses identified new risk loci and genes for inflammatory bowel disease.

To advance genetic understanding of inflammatory bowel disease (IBD), we conducted genome-wide association meta-analyses of 63,415 IBD cases of European and East Asian descendants and identified 90 previously unknown risk loci. Integrating multi-ancestry transcriptome-wide association studies (TWAS), cell type-specific TWAS, alternative splicing (AS-WAS), and alternative polyadenylation (APA-WAS) analyses using RNA-seq data from normal colon tissues of 707 European and 364 East Asian individuals, we uncovered 506 high-confidence IBD risk genes, including 384 not previously reported. These genes converge on immune regulation, microbial interaction, and other pathways central to IBD pathogenesis, with over half showing transcriptional dysregulation supported by single-cell and spatial omics analyses. Notably, 46 risk genes are targeted by 225 drugs that have been approved or in Phase II/III trials, including sulfasalazine already used in IBD therapy. Our study findings deepen the understanding of IBD genetics and support the development of precision medicine for its prevention and treatment.

GWAS↗

PubMed2026

Integrative cross-tissue transcriptome-wide association and metabolomic analysis reveals novel genetic risk loci for aortic aneurysm.

BACKGROUND: Aortic aneurysm (AA) is a life-threatening cardiovascular condition with a strong genetic component, however, its molecular mechanisms remain poorly understood. Although genome-wide association studies (GWAS) have identified numerous risk loci, most prior studies have investigated genetic and metabolic factors separately, leaving the causal pathways from genetic variants to disease largely unexplored. METHODS: We established an integrative framework combining cross-tissue transcriptome-wide association studies (TWAS) with metabolomic mediation analysis. First, we integrated GWAS data from FinnGen R12 with multi-tissue expression quantitative trait loci (eQTL) data from Genotype-Tissue Expression Project (GTEx) V8, then performed cross-tissue TWAS using the Unified Test for MOlecular SignaTures (UTMOST) and single-tissue validation with the Functional Summary-based Imputation (FUSION) to prioritize susceptibility genes. Second, we applied Mendelian randomization (MR), colocalization, and Fine-mapping Of CaUsal gene Sets (FOCUS) to assess causality and identify high-confidence genes. Third, we performed metabolite mediation analysis to uncover metabolic pathways linking genetic variants to disease risk. Finally, we validated key findings in mouse models of thoracic aortic aneurysm (TAA) and abdominal aortic aneurysm (AAA) using Quantitative Real-Time Reverse Transcription Polymerase Chain Reaction (RT-qPCR) and Western blotting. RESULTS: We identified multiple novel susceptibility genes for AA and its subtypes. Key genes included ADH family members (ADH1A, ADH1B, ADH4, ADH6) and ZNF827, which showed cross-subtype associations with strong colocalization evidence in vascular tissues. Metabolite mediation analysis revealed significant pathways involving N-acetylphenylalanine and methionine sulfoxide. Functional enrichment revealed distinct biological mechanisms: AA and AAA were primarily associated with metabolic pathways, whereas TAA-related genes were enriched in developmental and contractile processes. PheWAS indicated no significant off-target associations. Critically, experimental validation in mouse models confirmed significant upregulation of ZNF827 in TAA and ADH6 in AAA at both mRNA and protein levels, corroborating the genetic predictions. CONCLUSION: This integrated cross-omics analysis identifies novel genetic loci and, crucially, uncovers specific nutrient-related metabolic pathways that mediate genetic risk. These findings provide a mechanistic basis for future nutritional and metabolic intervention studies in AA and its subtypes.

MAGMA↗

PubMed1998

The impact of initial job assignment on formaldehyde exposure among African-American and white formaldehyde industry workers.

We compared initial job assignments of African-American and white employees at eight worksites that used formaldehyde between 1940 and 1979. Unexposed workers were excluded. Median, ambient air formaldehyde, 8-hour, time-weighted average (TWA8) exposure estimates were determined for each worksite. Job assignments with TWAs above the worksite's median TWA8 were called high formaldehyde exposed (HFE). Job assignments with TWAs less than or equal to the worksite's median TWA8 for the same period were called lower formaldehyde exposed (LFE). Two worksites assigned black workers to HFE jobs in significantly higher proportions than white workers in some decades. One worksite assigned white workers in significantly higher proportions than black workers to HFE jobs in some decades. One worksite assigned racial groups in nearly equal proportions from 1940 to 1969. The remaining sites showed insignificant assignment disproportions (alpha = 0.05; Chi-square < or = 3.841, 1 degree of freedom) for any period. No major trend was apparent across all plants and decades.

Black or African American↗

PubMed2001

Alternative magnetic field exposure metrics: relationship to TWA, appliance use, and demographic characteristics of children in a leukemia survival study.

The ongoing Childhood Leukemia Survival Study is examining the possible association between magnetic field exposure and survival of children with newly diagnosed acute lymphocytic leukemia (ALL). We report the results of the first year 24 h personal magnetic field monitoring for 356 US and Canadian children by time weighted average TWA and alternative exposure metrics. The mean TWA of 0.12 microT was similar to earlier personal exposure studies involving children. A high correlation was found between 24 h TWA and alternative metrics: 12 h day TWA, 12 night TWA, geometric mean, 95th percentile value, percentage time over 0.2 and 0.3 microT, and an estimate of field stability (Constant Field Metric). Two measures of field intermittency, rate of change metric (RCM) and standardized rate of change metric (RCMS), were not highly correlated with TWA. The strongest predictor of TWA was location of residence, with highest TWAs associated with urban areas. Residence in an apartment, lower paternal educational level, and residential mobility were also associated with higher TWAs. There were no significant differences in the appliance use patterns of children with higher TWA values. Children with the highest field intermittency (high RCM) were more likely to sit within 3 feet of a video game attached to the TV. Our results suggest that 24 h TWA is a representative metric for certain patterns of exposure, but is not highly correlated with two metrics that estimate field intermittency.

Adolescent↗

PubMed2000

Occupational exposure to nitrous oxide and desflurane during ear-nose-throat-surgery.

PURPOSE: To determine occupational exposure of the anesthesiologist and surgeon to nitrous oxide and desflurane during general anesthesia for ear-nose-throat (ENT) surgery in children and adults. METHODS: An observational clinical trial was performed in ten children (C) and ten adults (A). Tracheas were intubated, in adults, with cuffed tubes and in children with uncuffed tubes. The operating room was equipped with modern air conditioning and waste anesthetic gas scavengers. Gas samples were obtained during the operative procedure every 90 sec from the breathing zone of subjects. Time-weighted averages (TWA) over the time of exposure were calculated for nitrous oxide and desflurane. RESULTS: Nitrous oxide TWAs for anesthesiologists were 0.41 +/- 0.23 ppm (A) and 1.20 +/- 0.32 ppm (C, P < 0.0001), and 2.24 +/- 1.93 ppm (A) and 5.30 +/- 0.60 ppm (C, P = 0.0001) for the surgeon who worked close to the patient's airway and thus had higher exposure (P < 0.05 [A], P < 0.0001 [C]). With regard to desflurane, the anesthesiologists' TWAs were 0.02 +/- 0.03 ppm for both adults and children. The surgeon was exposed to 0.21 +/- 0.24 ppm desflurane (A) and 0.30 +/- 0.14 ppm (C, P: n.s.). Although the surgeon's exposure was greater (P < 0.05 [A], P < 0.0001 [C]), the threshold limits of 25 ppm for nitrous oxide and 2 ppm for desflurane recommended by the National Institute of Occupational Safety and Health were not exceeded. CONCLUSIONS: Under modern air conditioning, occupational exposure to inhalational anesthetics is low, and inhalational anesthesia is safe from the standpoint of modern workplace laws and health-care regulations.

Adult↗

PubMed2004

Fate and effects of the insecticide-miticide chlorfenapyr in outdoor aquatic microcosms.

The concentrations of chlorfenapyr in water and sediment in a lentic pond following early and late applications in a Florida crop treatment program were predicted using PRZM and EXAMS modeling and incorporating 30 years of actual rainfall data. An outdoor microcosm study was also conducted to determine the fate of chlorfenapyr and its effects on zooplankton, macroinvertebrates, phytoplankton, and fish in a freshwater system under exposure conditions representing simulated surface runoff and/or spray drift. The microcosm design used a regression model with five treatments (i.e., 300 microg/L spray, 30 microg/L spray, 15 microg/L spray and 30 microg/L runoff, 1.2 microg/L spray and 2.5 microg/L runoff, 30 microg/L runoff) plus a control. Chlorfenapyr was applied as an aqueous suspension concentrate (36% a.i.) to six microcosm tanks (30.9 m3). The no-observed-effect-concentration (NOEC) for zooplankton was the water concentration produced from the combination 1.2 microg/L spray and 2.5 microg/L runoff treatment. The NOEC for bluegill sunfish was the water concentration produced from the 30 microg/L runoff, which was significantly higher than the exposure concentrations from the lowest combination treatment. Chlorfenapyr was more toxic via spray to the water than via an exposure simulating surface runoff. The 96-h time weighted average concentrations (TWAs) from the lowest joint treatment and the 30 microg/L runoff treatment in the microcosm study were similar to model-predicted water 96-h TWA concentrations from early and late applications. The toxicity data from laboratory and microcosm studies along with water exposure data indicate low hazard to zooplankton species in the water column. Although chlorfenapyr remained in sediment, TWAs concentrations from the microcosm study along with model-predicted concentrations indicate low hazard to benthic invertebrate species based on acute toxicity to amphipods in the laboratory. Results from this assessment indicate that with appropriate measures to mitigate spray drift to shallow water bodies, applications of chlorfenapyr do not present a hazard to aquatic organisms during labeled uses.

Animals↗

PubMed2026

GWAS meta-analysis provides new insights into uveal melanoma risk.

OBJECTIVE: The aim of this research is to identify germline genetic variants that predispose to uveal melanoma (UM) using data from nine studies involving 5839 individuals with UM (3853 novel) and 349,863 healthy controls. METHODS: Five novel UM genome-wide association studies (GWAS) were performed and included for meta-analysis with four previously published UM GWAS. A fixed-effects inverse-variance weighted (IVW) meta-analysis was performed by combining data from these nine UM case-control cohorts. A follow-up transcriptome-wide association study (TWAS) was conducted to identify candidate target genes at UM risk loci. Genetic correlations with melanoma-related phenotypes were measured to elucidate UM's genetic architecture. RESULTS: We identify nine linkage disequilibrium (LD)-independent loci (three novel) with an IVW P value of less than 5 × 10-8. TWAS analysis indicates five potential target genes, including MOB3B, RBAK, and MTSS1, which have established links to multiple cancer types. We note a significant genetic correlation (rg = 0.31, P = 0.01) between UM and cutaneous melanoma (CM), and a non-significant but consistent correlation with naevus count (rg = 0.25, P = 0.08). CONCLUSIONS: This meta-analysis offers new insights into the genetic architecture of UM, highlights potential therapeutic targets, and explores the genetic relationship with CM and skin pigmentation.

Humans↗

PubMedDate not supplied

Evaluation of exposures to fluorocarbon 113 in a horizontal and a vertical laminar airflow clean room.

Exposures to 1,1,2-trichloro-1,2,2-trifluoroethane or fluorocarbon (FC) 113 were evaluated in a horizontal laminar airflow (HLAF) clean room and a vertical laminar airflow (VLAF) clean room. A full period consecutive samples measurement strategy was employed. Data were used to calculate 8-hour time-weighted averages (8-TWA) for major work groups and to characterize exposures associated with specific cleaning tasks. The MIRAN 1B infrared analyzer was used to estimate peak concentrations. In the HLAF clean room, 8-TWAs ranged from 193 to 439 ppm; in the VLAF clean room, 8-TWAs ranged from 110 to 935 ppm. These levels were below the current Occupational Safety and Health Administration permissible exposure limit and the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit for FC 113 of 1000 ppm. Short-term sample concentrations ranged from 104 ppm (inspection) to 1080 ppm (assembly) in the HLAF clean room and 51 ppm (packaging)-3380 ppm (flushing) in the VLAF clean room. In the VLAF clean room, several short-term concentrations measured during the flushing task--1421 ppm and 2522 ppm--were above the NIOSH short-term exposure limit (STEL) of 1250 ppm. These data suggest the possibility that the STEL may be exceeded for tasks involving direct work with liquid FC 113. Peak exposure levels may be reduced by modification of worker position in the HLAF clean room and by use of open wire tables in the VLAF clean room.

Air Pollutants↗

PubMedDate not supplied

An assessment of occupational noise exposures in four construction trades.

Three hundred thirty-eight noise exposure samples were collected from 133 construction workers employed in 4 construction trades: carpenters, laborers, ironworkers, and operating engineers. Four sites using a variety of construction techniques were sampled at least 12 times on a randomly chosen date over a 22-week period. Up to 10 volunteer workers were sampled for an entire work shift on each sampling day using datalogging noise dosimeters, which recorded both daily time-weighted averages (TWAs) and 1-min averages. Workers also completed a questionnaire throughout the workday detailing the tasks performed and tools used throughout the day. Regression models identified work characteristics associated with elevated exposure levels. Comparisons were made between exposures measured using the Occupational Safety and Health Administration (OSHA) exposure metric and the 1996 draft National Institute for Occupational Safety and Health/International Organization for Standardization (NIOSH/ISO) metric to examine the effects of differing exchange rates and instrument response times on construction noise exposures. The mean OSHA TWA for 338 samples was 82.8 dBA +/- 6.8 dBA, whereas the mean NIOSH/ISO TWA for 174 samples was 89.7 dBA +/- 6.0 dBA. Forty percent of OSHA TWAs exceeded 85 dBA, and 13% exceeded 90 dBA, the OSHA permissible exposure limit. The tasks and tools associated with the highest exposure levels were those involving pneumatically operated tools and heavy equipment. Trade was a poor predictor of noise exposure; construction method, stage of construction, and work tasks and tools used were found to be better exposure predictors. An internal validation substudy indicated excellent agreement between worker self-reporting and researcher observation. These data provide substantial documentation that construction workers in several key trades are frequently exposed to noise levels that have been associated with hearing loss, and demonstrate the need for targeted noise reduction efforts and comprehensive hearing conservation programs in the industry.

Humans↗

PubMed1988

Occupational noise exposure in the printing industry.

The noise exposures of 274 printing production workers in 34 establishments in the New York city area were monitored. Results showed that 43% were exposed to 8-hr time-weighted average (TWA) noise exposures of 85 dBA or greater and that 14% were exposed to 8-hr TWAs of 90 dBA or greater. Within the press department, web press workers were exposed to significantly greater mean 8-hr TWAs than sheetfed press workers. In general, a greater percentage of the workers in the bindery departments were exposed to potentially harmful noise than workers in the press departments. Results of this study indicate that many workers in the printing industry may be at risk of occupational hearing loss. Further research is needed to determine the extent of hearing impairment in this group of workers.

Environmental Exposure↗

PubMed1996

Comparison of daily noise exposures in one workplace based on noise criteria recommended by ACGIH and OSHA.

The objective of this study was to determine the impact of the new American Conference of Governmental Industrial Hygienists (ACGIHnew) noise criteria, as compared to the current U.S. Occupational Safety and Health Administration (OSHA) hearing conservation criteria, on the number of employees to be included in the hearing conservation program at one industrial facility. This study also compares the combined effects of a 3-dB versus a 5-dB exchange rate and an 80-dBA versus a 90-dBA measurement threshold on daily noise doses and equivalent 8-hr time-weighted averages (TWAs). Employee noise exposures were measured using paired Ametek MK-3 noise dosimeters, one dosimeter set to the ACGIHnew noise criteria and one to the present OSHA hearing conservation criteria. Samples were collected over 4-hr periods (half-shifts) for 50 employees in 7 job categories. Results indicate that the majority of the employees' exposures fell below an 8-hr TWAOSHA of 85 dBA. The differences between the predicted TWAACGIHnew and the TWAOSHA ranged between 0.2 and 12.6 dB for paired samples, with an average difference of 4.6 dB. Overall, these differences in employee 8-hr TWAs would project a 36% increase in the percent of the population enrolled in the hearing conservation program and a 50% increase in the percent of the population required to wear hearing protection.

Environmental Monitoring↗