American Conference Of Governmental Industrial Hygienists Research Articles

Biomonitoring for workplace exposure to copper and its compounds is currently not interpretable

This paper sets out to explore the requirements needed to recommend a useable and reliable biomonitoring system for occupational exposure to copper and its inorganic compounds. Whilst workplace environmental monitoring of copper is used to measure ambient air concentrations for comparison against occupational exposure limits, biological monitoring could provide complementary information about the internal dose of workers, taking into account intra-individual variability and exposure from all routes. For biomonitoring to be of reliable use for copper, a biomarker and the analytical ability to measure it with sufficient sensitivity must be identified and this is discussed in a range of matrices. In addition, there needs to be a clear understanding of the dose-response relationship of the biomarker with any health-effect (clinical or sub-clinical) or, between the level of external exposure (by any route) and the level of the copper biomarker in the biological matrix being sampled, together with a knowledge of the half-life in the body to determine accurate sampling times. For many biologically non-essential metals the requirements for reliable biomarkers can be met, however, for ‘essential’ metals such as copper that are under homeostatic control, the relationship between exposure (short- or long-term) and the level of any copper biomarker in the blood or urine is complex, which may limit the use and interpretation of measured levels. There are a number of types of biomarker guidance values currently in use which are discussed in this paper, but no values have yet been determined for copper (or its inorganic compounds) due to the complexity of its essential nature; the US The American Conference of Governmental Industrial Hygienists (ACGIH) has however indicated that it is considering the development of a biological exposure index for copper and its compounds. In light of this, we present a review of the reliability of current copper biomarkers and their potential use in the occupational context to evaluate whether there is value in carrying out human biomonitoring for copper exposure. Based on the available evidence we have concluded that the reliable use of biomonitoring of occupational exposure to copper and its application in risk assessment is not possible at the present time.

Comparison and analysis research on occupational exposure limits of coal dust between China and foreign countries

Objective: To study and compare the occupational exposure limits (OELs) of coal dust between China and foreign countries, understand the OEL of coal dust in China, and provide data and basis for revising the OEL of coal dust in China. Methods: In August 2023, by searching the official websites of limits setting institutions in relevant countries and regions at home and abroad, collecting and sorting out the OELs of coal dust issued by 10 limit setting institutions in 6 countries and the background information of the formulation, and conducting specific analysis on the classification, limit level and formulation principles of coal dust OEL in each country/institution. Results: In China and Japan, the total dust and respirable dust of coal dust OEL were established respectively, while in other countries, only the time-weighted average concentration (TWA) of respirable coal dust exposure was established. The TWA prescribed by China's Notional Health Commission, the United States Occupational Safety and Health Administration (OSHA) , the United States Mining Safety and Health Administration (MSHA) and the Australian Safety Work Bureau when the SiO(2) content was less than 5% were 5, 2.4, 2 and 3 mg/m(3) respectively. China GBZ 2.1-2019 sets the limit of 2.5 mg/m(3) for respirable coal dust with SiO(2) content less than 10%. The TWA set by the American Conference of Government Industrial Hygienists (ACGIH) and the South African Department of Mines and Energy (DME) for anthracite coal were 0.4 and 0.8 mg/m(3), respectively, and bituminous coal or lignite were 0.9 and 1.8 mg/m(3), respectively. The respirable coal dust TWA set by the National Institute for Occupational Safety and Health (NIOSH) in the United States was 1 mg/m(3), and the TWA set by the New Zealand Work Safety Authority was 3 mg/m(3). Conclusion: At present, the OEL of coal dust in China is at a relatively loose level, and it is suggested to further explore the possibility of revising coal dust OEL.

The ACGIH TLV for lifting: Estimated TLVs for torso asymmetry beyond 30 degrees.

The American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) for Lifting is a manual material handling (MMH) assessment method to identify weight limits that nearly all workers may be exposed to without developing work-related low back disorders (LBD). However, this assessment method only applies to lifting with the torso within 30° asymmetry of the sagittal plane. Estimate TLV weight limits while lifting with torso asymmetry greater than 30° beyond the sagittal plane. Lifting tasks were performed from various horizontal and vertical locations, at torso asymmetry angles of 0°, 15°, 30°, 45°, 60°, 75° and 90°, using ACGIH identified TLVs. Validated MMH assessment methods (NIOSH Lifting Equation, Ohio State University LBD Risk Model) were utilized to estimate TLVs at torso asymmetries greater than 30°. The current ACGIH TLVs resulted in low- to moderate-risk risk levels for torso asymmetries from 0° to 30°, and the risk incrementally increased as torso asymmetry increased to 90°. With the intention to keep the risk levels to that found at 30° torso asymmetry, lower TLV weight limits in the vertical and horizontal zones investigated were estimated for torso asymmetries from 45° to 90°. The resulting adjusted TLVs were consistent with weight limits identified for similar lifting conditions from other assessment methods that account for torso asymmetry. This research found current ACGIH-defined TLVs possess less than high-risk for LBD, and provided guidance to practitioners for reduced TLVs when torso asymmetry is greater than 30° from the sagittal plane.

Hazards associated with blue light emitted during gas metal arc welding of mild steel using various shielding gases and currents.

Blue light emitted during arc welding is known to potentially cause photoretinopathy. To help prevent retinal injury, it is important to identify the hazards associated with various welding conditions. The present work conducted experiments involving gas metal arc welding of mild steel under various conditions, and measured the spectral radiance of the arcs. The effective radiance values, as used by the American Conference of Governmental Industrial Hygienists (ACGIH) to quantify exposure level of blue light, were subsequently calculated from the data. The resulting values were in the range of 5.0-118 W/cm2/sr, corresponding to hazardous levels according to ACGIH guidelines. The effective radiance was increased at higher welding currents and when pulsed currents were used rather than steady currents. The blue light hazard was also affected by the type of shielding gas employed. These data confirm that it is very hazardous to stare at arcs during gas metal arc welding of mild steel. As such, appropriate eye protection is necessary during arc welding, and directly staring at the arc should be avoided.

Gasoline Generators and their Effects on Air Quality of Some Selected Business Centers in Tertiary Institutions in Rivers State

This study considered gasoline generators and their effects on air quality of some selected business centers in tertiary institutions in Rivers State. Air quality monitor was positioned 1.5m above the floor to determine the concentration levels of CO, CO2 and O2. The measurements were done on a daily for a period of three weeks. At FCE (T), Omoku, the mean concentration values of CO for Business and Institution’s generators were 109.2ppm and 62.3ppm; CO2 283.6ppm and 27.4ppm and O2 185.8% and 192.1% respectively. At IAUE, Port-Harcourt, CO for Business and Institution’s generators had mean concentration values of 144.7ppm and 89.6ppm; CO2 210.9 ppm and 188.8ppm, and for O2, 225.4% and 239.2% respectively. Similarly, for RSU, Port-Harcourt, the mean concentration of CO for Business and Institution’s generators were 144.8ppm and 84.5ppm; CO2 171.1ppm and 124.ppm; and for O2, 196.8% and 164.3%. respectively. CEAP, Port-Harcourt, CO had mean concentration values of 215.3ppm and light 92.2ppm, CO2 226.2ppm and 109.2ppm, whileO2 mean concentration values of 120.1% and 198.2% respectively. The concentration levels of CO, CO2 for business generators were much higher compared to when Institutions’ generators were used. The mean values of CO concentrations for the selected institutions for the period under study were higher than OSHA permissible exposure limit (PEL) of 50ppm (55mg/m3), NIOSH recommended exposure limit (REL) of 35ppm (40 mg/m3) and ACGIH threshold limit value (TLV) of 25ppm (28.6mg/m3), while that of CO2 concentration levels were less than OSHA’s established permissible limit of 5000ppm, and American Conference of Governmental Industrial Hygienists(ACGIH) threshold limit value (TLV) of 25ppm. It was also observed that as the concentrations of CO and CO2 increase, the O2 levels also decrease. It is therefore, very important to state that tertiary institutions’ managements in Nigeria should consider the provision of regular power supply on

Carcinogenic and non-carcinogenic risk of exposure to metal fume in different types of welding processes.

The international agency for cancer research (IARC) has classified welding fumes as definitive carcinogens. The aim of the present study was to assess health risk due to exposure to welding fumes in different welding types. In this study, exposure to fumes of iron (Fe), chromium (Cr), and nickel (Ni) in the breathing zone air of 31 welder engaged in arc, argon and CO2 welding was assessed. Carcinogenic and non-carcinogenic risk assessments due to exposure to fumes were performed using the method proposed by the Environmental Protection Agency (EPA) by Monte Carlo simulation. The results showed that in the CO2 welding, concentration of Ni, Cr, and Fe was lower than the 8-h Time-Weighted Average Threshold Limit Value (TWA-TLV), recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). In argon welding, Cr and Fe concentrations were higher than the TWA-TLV. In arc welding, concentrations of Ni and Fe were more than the TWA-TLV. In addition, the risk of non-carcinogenicity due to exposure to Ni and Fe in all three types of welding was more than standard level (HQ>1). The results indicated that the welders are at health risk due to exposure to metal fumes. Preventive exposure control measures such as local ventilation need to be implemented in welding workplaces.

Metal-organic frameworks derived inverse/normal bimetallic spinel oxides toward the selective VOCs and H2S sensing

As the typical toxic and hazardous gases, volatile organic compounds (VOCs) and hydrogen sulfide (H2S) pose a threat to the environment and human health. The demand for real-time detection of VOCs and H2S gases is growing in many application to protect human health and air quality. Therefore, it is essential to develop advance sensing materials for the construction of effective and reliable gas sensors. Herein, bimetallic spinel ferrites with different metal ions (MFe2O4, M = Co, Ni, Cu and Zn) were designed by using metal-organic frameworks as templates. The evaluation of cation substitution on crystal structures (inverse/normal spinel structure) and electrical properties (n/p type and band gap) is systematically discussed. The results indicate that p-type NiFe2O4 and n-type CuFe2O4 nanocubes with inverse spinel structure exhibit high response and great selectivity towards acetone (C3H6O) and H2S, respectively. Moreover, the two sensors also display the detection limits as low as 1 ppm (C3H6O) and 0.5 ppm (H2S), which are far below the threshold values of 750 ppm to acetone and 10 ppm to H2S for 8 h exposure set by American Conference of Governmental Industrial Hygienists (ACGIH). The finding provides new possibilities for the design of high-performance chemical sensors, which display tremendous potential for practical applications.

A Twenty-Year Retrospective Analysis of Risk Assessment of Biomechanical Overload of the Upper Limbs in Multiple Occupational Settings: Comparison of Different Ergonomic Methods.

Several methods with which to assess the risk of biomechanical overload of the upper limb are described in the literature. We retrospectively analysed the results of the risk assessment of the biomechanical overload of the upper limb in multiple settings by comparing the application of the Washington State Standard, the threshold limit values (TLV) proposed by the American Conference of Governmental Industrial Hygienists (ACGIH), based on hand-activity levels (HAL) and normalised peak force (PF), the Occupational Repetitive Actions (OCRA) checklist, the Rapid Upper-Limb Assessment (RULA), and the Strain Index and Outil de Repérage et d'Evaluation des Gestes of INRS (Institut National de Recherche et de Sécurité). Overall, 771 workstations were analysed for a total of 2509 risk assessments. The absence of risk demonstrated for the Washington CZCL, used as the screening method, was in good agreement with the other methods, with the sole exception of the OCRA CL, which showed at-risk conditions in a higher percentage of workstations. Differences in the assessment of the frequency of actions were observed among the methods, while their assessments of strength appeared to be more uniform. However, the greatest discrepancies were observed in the assessment of posture. The use of multiple assessment methods ensures a more adequate analysis of biomechanical risk, allowing researchers to investigate the factors and segments in which different methods show different specificities.

Alterations to biomarkers related to long-term exposure to diesel exhaust at concentrations below occupational exposure limits in the European Union and the USA

BackgroundWe previously found that occupational exposure to diesel engine exhaust (DEE) was associated with alterations to 19 biomarkers that potentially reflect the mechanisms of carcinogenesis. Whether DEE is associated with...

Chromium toxicity among leather industry workers in Kolkata-A pilot Study

Introduction: Chromium (Cr) exposure is known to cause various health issues such as cancer, dermatitis, respiratory problems, etc. The recent exposure of Cr can be determined by analysis of Cr either in blood/urine/plasma, Cr (III) ions cannot permeate through cell membranes of red blood cells (RBC) because their ionic radii are bigger as compared to Cr (VI), and hence Cr in RBC is an indicator for exposure to Cr (VI) ions. The purpose of this study was to investigate chromium exposure, hygienic habits and the occurrence of dermatological problems with leather industry workers in Kolkata. Methods: A total of 68 leather industry workers with minimum work exposure of five years and aged between 18-60 years were recruited for this study. The study protocol included a questionnaire and analysis of Cr in blood and urine samples by GF-AAS. Results: All values were under the Biological Exposure Index (BEI) of 25µg /L at the end of the shift of a five-day work week recommended by the American Conference of Governmental Industrial Hygienists (AcGIH). 15.2% of subjects suffered from dermatological problems at least once in the last year during work in the leather industry. Conclusion: It was found that leather industry workers were not using personal protective equipment and it must be promoted to them for occupational health and safety.

Assessment of safety control measures for centralized Chlorine gas system

As a glove manufacturing plant, the chemical is one of the most highly used materials. Some chemicals impact human health, environmental aspects, and physical hazards such as highly flammable gas. Chlorine gas is one of them. Besides the accidental release of chlorine gas incidents, ill-health issues are another aspect that should be taken care of. This study aims to determine the current chlorine concentration at a centralized chlorine gas manifold system in a rubber glove manufacturing plant and evaluate the existing safety control measures. A concept of safety by design, inherently safety, and the fail-safe system was considered during the study. The results show that the chlorine concentration level during drum replacement by the crew is at an average of 1.154 ppm and the standard deviation at 0.3478. The highest concentration was at 1.8 ppm. The wet scrubber assessment was done using the Industrial Ventilation and visual assessments and measurements within the system, including capture velocity, face velocity, and duct velocity or transport velocity. Other assessed parameters are total pressure, static pressure, and velocity pressure. The assessment found that the duct performance for all parameters complies with a minimum requirement of the American Conference of Governmental Industrial Hygienists (ACGIH) guidelines.

Research on the relationship between the centerline velocity, aspect ratio and exhaust airflow rate for a slot and a rectangular capture hood in an local exhaust ventilation system.

When using a local exhaust hood to remove harmful substances from the production process, the exhaust airflow rate must be calculated according to the capturing velocity specified by the relevant regulations. The Numano and American Conference of Governmental Industrial Hygienists (ACGIH) equations are used in Japan and the US, respectively, for estimating the exhaust airflow rate of slot hoods. However, these equations differ from each other, and when using these equations to calculate the exhaust airflow rate of the capture hood, whether using Japan's equation or ACGIH, the hood type (slot or rectangular hood) should be distinguished at first. Therefore, this study performs experiments and a computational fluid dynamics (CFD) simulation to investigate the relationship between the centerline velocity and the aspect ratio for five types of capture hoods. The results showed good agreement between simulated and experimental centerline velocities when the distance from the hood face. A dimensionless velocity was introduced and a significant difference in the relationship between the centerline velocity and the distance from the hood face with different aspect ratios was found. A unified equation was obtained that can express the relationship between exhaust airflow rate and centerline velocity regardless of the aspect ratio of the hood face of the free-standing capture hood.

Potential harm to the skin from unfiltered krypton chloride ‘far-ultraviolet-C’ lamps, even below an occupational exposure limit

Ultraviolet-C (UVC) radiation can effectively inactivate pathogens on surfaces and in the air. Due to the potential for harm to skin and eyes, human exposure to UVC should be limited within the guideline exposure limits produced by the International Commission on Non-Ionising Radiation Protection (ICNIRP) or the American Conference of Governmental Industrial Hygienists (ACGIHs). Both organisations state an effective spectrally weighted limit of 3 mJ cm−2, although the spectral weighting factors of the two organisations diverged following a revision of the ACGIH guidelines in 2022. Using existing published human exposure data, the effective spectrally weighted radiant exposure was calculated for both unfiltered and filtered (to reduce UV emissions above 230 nm) krypton chloride (KrCl*) excimer lamps. The effective radiant exposure of the filtered KrCl* lamp was greater than 3 mJ cm−2 when applying ICNIRP or either of the revised ACGIH spectral weightings. This indicates that both guidelines are appropriately conservative for this specific lamp. However, the effective radiant exposure of the unfiltered KrCl* lamp was as low as 1 mJ cm−2 with the revised ACGIH weighting function that can be applied to the skin if the eyes are protected. Erythema has therefore been directly observed in a clinical study at an exposure within the revised ACGIH guideline limits. Extrapolating this information means that a mild sunburn could be induced in Fitzpatrick skin types I and II if that particular ACGIH weighting function were applied and an individual received an effective exposure of 3 mJ cm−2. Whilst it is improbable that such an effect would be seen in current deployment of KrCl* lamp technology, it does highlight the need for further research into skin sensitivity and irradiance–time reciprocity for UVC wavelengths.

Engineered Stone Fabrication Work Releases Volatile Organic Compounds Classified as Lung Irritants.

Engineered stones are often characterized for their crystalline silica content. Their organic composition, particularly that of the emissions generated during fabrication work using hand-held power tools, is relatively unexplored. We forensically screened the emissions from dry-cutting 12 engineered stone products in a test chamber for their organic composition by pyrolysis-gas chromatography-mass spectrometry (GC-MS) plus selected traditional capture and analysis techniques. Phthalic anhydride, which has a Respiratory Sensitization (RSEN) Notation by the American Conference of Governmental Industrial Hygienists (ACGIH), was the most common and abundant compound, at 26-85% of the total organic composition of engineered stone emissions. Benzaldehyde and styrene were also present in all twelve samples. During active cutting, the predominant volatile organic compound (VOC) emitted was styrene, with phthalic anhydride, benzene, ethylbenzene, and toluene also detected. These results have important health implications as styrene and phthalic anhydride are irritants to the respiratory tract. This study suggests a risk of concurrent exposure to high levels of respirable crystalline silica and organic lung irritants during engineered stone fabrication work.

Derivation of maximum permissive switching time for automatic welding filter based on retinal thermal and blue light exposure limits

Automatic welding filters are intended to protect the eyes of the welder from optical radiation generated by the welding process. Safety standards for automatic welding filters (AWFs) have been developed worldwide. However, switching time requirements have not been studied considering the exposure limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) or the American Conference of Governmental Industrial Hygienists (ACGIH). The aim of this study is to derive the maximum permissive switching time based on ICNIRP guidelines for exposure to intense optical radiation. The single and cumulative exposures associated with retinal thermal and blue light hazards were assessed in the welding environment. The results show that the maximum switching time is inversely proportional to the exponential function of the shade number difference. The proposed maximum switching time, 1/2 to 1/10 smaller than the current ISO, is derived from the effective blue light radiance limits. In addition, an evaluation of the periodic short circuit welding indicates that AWFs do not transmit hazardous levels of radiation in the dark state.

Evaluation of hand-arm vibration(HAV) exposure levels among grounds maintenance workers: An observational human exposure measurement study.

Evaluation of hand-arm vibration(HAV) exposure levels among grounds maintenance workers: An observational human exposure measurement study.

Job Stress among Workers Exposed to Extremely Low Frequency Electric and Magnetic Fields in a Combined Cycle Power Plant

Introduction: Exposure to the low frequency electric and magnetic fields (ELF-EMF) is very common in workers occupied in the combined cycle power plant during work shifts The present study aimed to measure ELF-EMF flux density among shift and non-shift workers, determine job stress among workers and office workers, and identify major factors associated with job stress in the studied groups.
 Materials and Methods: In this cross-sectional study, the exposed group was divided into 75 shift workers and 75 non-shift workers. Seventy-five office workers were selected as the reference group. The participants’ exposure to ELF-EMF was measured by the EMF-828 device. In addition, Osipow Occupational Stress Questionnaire was used to assess the participants’ stress levels.
 Results: Maximum levels of ELF-EMF among shift workers, non-shift workers, and office workers were 28.67 μT, 23.43 μT, and 0.06 μT, respectively. Although the explosion rate to ELF-EMF was higher in the shift and non-shift workers than the office one's, this rate in both of them were lower than the recommended limit as suggested by the American Conference of Governmental Industrial Hygienists (ACGIH). The highest stress score was related to shift workers exposed to ELF-EMF, in which 42.7% of them experienced moderate to high levels of job stress. Multivariate linear regression analysis showed a significant association between shift work and exposure to ELF-EMF with increased stress.
 Conclusion: The findings suggested that exposure to ELF-EMF, even at low intensities, is associated with increased stress. Moreover, Shift work is another risk factor for stress.

Implementation of Chemical Health, Safety, and Environmental Risk Assessment in Laboratories: A Case-Series Study.

IntroductionCharacterizing risks associated with laboratory activities in universities may improve health, safety, and environmental management and reduce work-related diseases and accidents. This study aimed to develop and implement a chemical risk assessment method to determine and prioritize more hazardous chemicals in the academic laboratories.MethodsA case-series study was conducted at five academic laboratories and research facilities of an Iranian medical sciences university in 2021. A risk assessment was developed and implemented in three phases to identify, evaluate, and classify potential risks and hazards. The approach provided an innovative tool for evaluating and prioritizing risks in chemical laboratories. Hazards were classified on a five-level scale. The technique reviewed both quantitative and qualitative data and pieces of evidence using Laboratory Safety Guidance (OSHA), Occupational Hazard Datasheet (ILO), the standards of the American Conference of Governmental Industrial Hygienists (ACGIH), International Agency for Research on Cancer (IARC), and National Fire Protection Agency (NFPA) codes.ResultsOverall, the frequency of risks rated from “moderate” to “very high” levels was determined for the health hazards (9.3%), environmental hazards (35.2%), and safety hazards (20.4%). Hydrochloric acid had a high consumption rate in laboratory operations and received the highest risk levels in terms of potential hazards to employees' health and the environment. Nitric acid, Sulfuric acid, Formaldehyde, and Sodium hydroxide were assessed as potential health hazards. Moreover, Ethanol and Sulfuric acid were recognized as safety hazards. We observed adequate security provisions and procedures in academic laboratory operations. However, the lack of awareness concerning health, safety, environmental chemical hazards, and inappropriate sewage disposal systems contributed to the increasing levels of laboratory risk.ConclusionsChemicals used in laboratory activities generate workplace and environmental hazards that must be assessed, managed, and risk mitigated. Developing a method of rating health, safety, and environmental risks related to laboratory chemicals may assist in defining and understanding potential hazards. Our assessment suggested the need for improving the risk perception of individuals involved in handling chemicals to prevent exposure from workplace duties and environmental pollution hazards.

Occupational Exposure to Metal Fumes Among Iranian Welders: Systematic Review and Simulation-Based Health Risk Assessment.

There have been numerous reports of welder's worker exposure to metal fumes. Carcinogenic and non-carcinogenic (neurological, dermal, and etc.) effects are the adverse outcomes of exposure to welding fumes. In this review study, data were collected from previous studies conducted in Iran from 1900 to 2020. The risk of carcinogenicity and non-carcinogenicity due to exposure to welding metal fumes was assessed using the United States Environmental Protection Agency (USEPA) method based on the Monte Carlo simulation (MCS). Results showed mean of metal fume concentration in gas welding was in the range of 1.8248 to 1060.6 (µg/m3) and in arc welding was 54.935 to 4882.72 (µg/m3). The mean concentration of fumes in gas welding is below the recommended American Conference of Governmental Industrial Hygienists (ACGIH) standard exposure limit except for manganese, and in the arc welding, all metal fume concentrations are below the standard exposure limit except for manganese and aluminum. The results showed that the risk of carcinogenicity due to exposure to nickel, manganese in both gas and arc welding, and cadmium in gas welding was higher than standard level (hazard quotient (HQ) more than 1). Cancer risk due to exposure to nickel in both gas and arc welding was probable (1 × 10-6 < cancer risk (CR) < 1 × 10-4). Health risk assessment showed that welders are exposed to health risks. Preventive measures should be applied in welding workplaces to reduce the concentrations of metal fumes.

Exposure assessment of polycyclic aromatic hydrocarbons in refined coal tar sealant applications.

Refined coal tar sealant (RCTS) emulsions are used to seal the surface of asphalt pavement. Nine of the 22 polycyclic aromatic hydrocarbons (PAHs) evaluated in this study are classified as known, probable, or possible human carcinogens. Exposure assessment research for RCTS workers has not been published previously. The overall objective of this study was to develop a representative occupational exposure assessment of PAH exposure for RCTS workers based on worksite surveys. The specific aims were to: 1) quantify full-shift airborne occupational exposures to PAHs among RCTS workers; 2) quantify workers' dermal exposures to PAHs; 3) quantify biomarkers of PAH exposure in workers' urine; 4) identify specific job titles associated with RCTS exposure; and 5) apply these results to a biological exposure index to assess risk of potential genotoxicity from occupational exposures. A total of twenty-one RCTS workers were recruited from three companies. Personal and area air samples were collected using a modification of NIOSH Method 5515. Dermal exposure was assessed by hand and neck wipes before and after shifts. Twenty-two PAHs were quantified via gas chromatography-mass spectrometry selected ion monitoring. Internal dose was estimated by quantifying select PAH metabolites in pre- and post-shift urine samples using on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry. PAH levels in the worker breathing zones were highest for naphthalene, acenaphthene, and phenanthrene, with geometric means of 52.1, 11.4, and 9.8μg/m3, respectively. Hand wipe levels of phenanthrene, fluoranthene and pyrene were the highest among the 22 PAHs with geometric means of 7.9, 7.7, and 5.5μg/cm2, respectively. Urinary PAH biomarkers for naphthalene, fluorene, phenanthrene, and pyrene were detected in all workers and were higher for post-shift samples than those collected pre-shift. Urinary concentrations of the metabolite 1-hydroxypyrene were greater than the American Conference of Governmental Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) for this metabolite in 89 percent of post-shift samples collected on the final day of the work week or field survey. Statistically significances were found between concentrations of fluorene, naphthalene, and phenanthrene in the breathing zone of workers and their corresponding urinary PAH biomarkers. Workers were placed in two work place exposure groups: applicators and non-applicators. Applicators had higher total PAH concentrations in personal breathing zone (PBZ) air samples than non-applicators and were more likely to have post-shift hand wipe concentrations significantly higher than pre-shift concentrations. Concentrations of post-shift urinary biomarkers were higher, albeit not significantly, for applicators than non-applicators. The exposure results from RCTS worker samples cannot be explained by proximal factors such as nearby restaurants or construction. Air and skin concentration levels were substantially higher for RCTS workers than previously published levels among asphalt workers for all PAHs. PAH profiles on skin wipes were more consistent with RCTS sealant product than air samples. Last day post-shift urinary concentrations of 1-hydroxypyrene greatly exceeded the ACGIH BEI benchmark of 2.5μg/L in 25 of 26 samples, which suggests occupational exposure and risk of genotoxicity. When pyrene and benzo[a]pyrene were both detected, concentration ratios from personal exposure samples were used to calculate the adjusted BEI. Concentrations of 1-hydroxypyrene exceeded the adjusted BEIs for air, hand wipes, and neck wipes in most cases. These results indicate the need to increase safety controls and exposure mitigation for RCTS workers.