A temporal evaluation of respirable crystalline silica exposure for construction tasks.

Personal air monitoring using a TSI SidePak AM520 personal aerosol monitor was performed on a northern Colorado construction site during five tasks from the OSHA Table 1: Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica to estimate silica dust concentrations in real time. Photometric measurements were modified using a gravimetric correction factor and a % respirable crystalline silica adjustment. Each task was sampled once; sample time ranged from 14 min to 40 min, with a mean sample time of 27 min. The mean silica dust concentration estimates (µg/m3) (standard deviation [SD]) for the five tasks computed from the TSI SidePak AM520 respirable dust measurements were core drilling 12 µg/m3 [2.46], grinding 918 µg/m3 [1134.08], cutting with a walk-behind saw 36 µg/m3 [79.67], jackhammering 27 µg/m3 [23.24], and dowel drilling 66 µg/m3 [77.65]. Silica exposure estimates from real-time monitoring can be used to identify exposures that may be related to inadequate controls or worker behaviors that contribute to peak exposures. Respirable crystalline silica exposure estimates presented here are likely not generalizable to other construction sites or tasks.

The Evaluation of Worker Exposure to Airborne Silica Dust During Five OSHA Table I Construction Tasks.

Fifty-one (51) personal silica air samples were collected over 13 days on 19 construction employees while they performed five different construction tasks found in the Occupational Safety and Health Administration's (OSHA) respirable crystalline silica standard for construction, Table 1, which specifies engineering, work practice, and respiratory protection controls that employers can use in lieu of exposure monitoring to adhere to the standard. The average construction task time was 127 min (range: 18-240 min) with a mean respirable silica concentration of 85 µg m-3 (standard deviation [SD] = 176.2) for all 51 measured exposures. At least one OSHA-specified silica dust control measure was used during all 51 samples collected. The mean silica concentrations for the five tasks were: core drilling 11.2 µg m-3 (SD = 5.31 µg m-3), cutting with a walk-behind saw 126 µg m-3 (SD = 115 µg m-3), dowel drilling 99.9 µg m-3 (SD = 58.7 µg m-3), grinding 172 µg m-3 (SD = 145 µg m-3), and jackhammering 23.2 µg m-3 (SD = 5.19 µg m-3). Twenty four of 51 (47.1%) workers were exposed above the OSHA Action Level (AL) of 25 µg m-3 and 15 of 51 (29.4%) were exposed above the OSHA Permissible Exposure Limit (PEL) of 50 µg m-3 when exposures were extrapolated to an 8-h shift. When silica exposures were extrapolated to 4 h, 15 of 51 (29.4%) of workers sampled were exposed over the OSHA AL and 8 of 51 (15.7%) were exposed over the OSHA PEL. A total of 15 area airborne respirable crystalline silica samples were collected on days where the personal task-based silica samples were taken, with an average sampling time of 187 min. Of the 15 area respirable crystalline silica samples, only four were greater than the laboratory reporting limit of 5 µg m-3. The four area silica samples with reportable concentrations revealed background silica concentrations of 23 µg m-3, 5 µg m-3, 40 µg m-3, and 100 µg m-3. Odds ratios were used to analyze the apparent association between dichotomous background construction site exposures to respirable crystalline silica (detectable or not detectable), and personal exposure category (over or not over the OSHA AL and PEL) when exposure times were extrapolated to 8 h. The associations were strongly positive and significant between detectable background exposures and personal overexposures for workers conducting the five Table 1 tasks with engineering controls in place. The results of this study suggest that exposure to hazardous levels of respirable crystalline silica may be present even when OSHA-specified engineering controls are implemented. The current study findings also suggest that background construction site silica concentrations may potentially cause task-based overexposures, even when the OSHA Table 1 control methods have been put in place.

The associations between occupational health and safety management system programming level and prior injury and illness rates in the U.S. dairy industry.

U.S. dairy workers suffer occupational injuries and illnesses at rates higher than the national average. Occupational health and safety management systems (OHSMS) have been proposed as a way to reduce injuries and illnesses for businesses of all types and sizes. The Occupational Safety and Health Administration (OSHA) On-Site Consultation Service provides assistance establishing an OHSMS to U.S. businesses. As part of this service, the consultants determine the level of OHSMS programming using the Safety and Health Program Assessment Worksheet (Revised OSHA Form 33). A total of 167 dairy industry records were obtained from OSHA. Forty-five of those records had both injury rate and OHSMS data. Using these records, a Spearman Rank-Order correlation was used to determine the strength and significance of the associations between prior injury rates and OSHA measured OHSMS programming level for dairy operations. Additional analyses were conducted to examine potential relationships between workforce size, injury rates, and OHSMS programming levels. There was a negative correlation between OHSMS programming level and injury rates, both for the overall OHSMS and by OHSMS component. Management Leadership was the OHSMS component most strongly associated with lower injury and illness rates. OHSMS interventions, as part of a comprehensive risk management approach for the U.S. dairy industry, may be warranted to help reduce the unacceptable number of injury and illnesses in the U.S. dairy industry. Further research is needed to determine if similar relationships between OHSMS programming and injury rates occur in other industries.

Effects of Residential Environmental Screening and Perception Surveys on Superfund Environmental Health Risk Perceptions.

Residents at one of the nation's largest and longest-operating Superfund sites (Butte, Montana) have expressed environmental health risk perceptions that often diverge from those of EPA and other official stakeholders responsible for the investigation and remediation of site contamination aimed at protecting human health and the environment. A random sample of Butte residents participated in a study of how home-based environmental screening influences environmental health perceptions. Participants completed surveys measuring environmental health perceptions before and after a home site screening of soil and drinking water for lead and arsenic conducted by the research team. Local air monitoring for the same contaminants was also completed during the study period. The home-based screening intervention improved the alignment of subjective participant environmental health perceptions with objective environmental screening measures. Key features of the process that helped achieve this effect included (1) co-locating the collection of participant perceptions and individualized screening measurements; (2) sharing environmental screening results in a clear and unbiased manner; and (3) conducting this work independent of agencies and organizations with direct responsibility for Superfund-related cleanup activities. Empowering residents of a Superfund community with knowledge of the specific kinds and levels of environmental contamination in their home environment may help overcome the gap between agency conclusions regarding environmental health risk and the perceptions of community members.

Are hard hats a risk factor for WRMSD in the cervical-thoracic region?

OBJECTIVES: To investigate the effect of wearing hard hats on the lower cervical and upper thoracic region using surface electromyography (sEMG) and possible link to work-related musculoskeletal disorder (WRMSD). METHODS: Twenty study subjects wore sEMG sensors placed on the upper trapezius muscle on their dominant side to assess muscle activity while wearing different hard hats. Study subjects were asked to don six different hard hats and assume varied neck postures. A repeated-measures design was used to analyze the results for difference and similarities in muscle activity. RESULTS: There was a small, significant effect of wearing a hard hat on muscle loading in the upper trapezius (p = 0.038). Post-hoc analyses revealed the only statistically significant difference was between wearing no hard hat at all and wearing head protection (without accessories) in the flexed posture (p = 0.006). CONCLUSION: The results demonstrated that there was little difference in lower cervical and upper thoracic muscle activity while donning hard hat and assuming various neck postures. Wearing a sample of commonly used hard hats in this study does not appear to substantially increase muscle activity that would cause fatigue in the lower cervical and upper thoracic region among young, healthy volunteer subjects.

Control of wildfire-sourced PM2.5 in an office setting using a commercially available portable air cleaner.

A steady increase in wildfire event severity and season length has led to greater potential for exposure to fine particulate matter associated with wildfire smoke. Research has found fine particulate matter to be correlated with a myriad of health ailments and thus effective strategies for controlling exposures are needed. In this study, a correction factor associated with wildfire-sourced fine particulate matter was established for a TSI SidePak AM520 by conducting sampling with a co-located MetOne BAM 1020. Portable air cleaner efficacy was assessed by simultaneously measuring PM2.5 mass concentrations in two identical offices with the inclusion of a portable air cleaner in one. The relationship between indoor and outdoor PM2.5 mass concentrations was assessed by comparing concentrations recorded in an office to those recorded at the nearest National Ambient Air Quality Standards monitoring station. Results revealed that a portable air cleaner reduced indoor fine particulate matter within an office by 73% and 92% during working and non-working hours, respectively, and that a strong significant correlation (ρ = .91, p = 0.00) existed between indoor and outdoor fine particulate matter mass concentration measurements. A direct relationship between indoor and outdoor PM2.5 mass concentrations was observed during this study, suggesting that elevated fine particulate matter concentrations due to wildfire smoke could be a concern in the indoor work environment; however the current study determined that the use of a portable air cleaner can substantially decrease fine particulate matter concentrations even in an active office setting.

Environmental health perceptions in a superfund community.

A disconnect between community perceptions and officially documented Superfund remedial actions and health outcomes may hinder the essential community engagement at Superfund sites. This study evaluates the extent of one such potential disconnect in Butte, Montana, which is part of the largest U.S. Superfund site in the U.S. Since the 1860s, when mining began in Butte, mine waste disposal practices in Butte and surrounding areas have left behind massive deposits that have contaminated the area's soil, sediment, groundwater and surface water with arsenic and heavy metals. Over the last four decades, a substantial amount of remediation work has been completed along with requisite community engagement and health studies at this Superfund site. The potential disconnect was evaluated using a new survey instrument that covered: (a) general environmental health perceptions, (b) mine-waste specific environmental health perceptions, (c) effectiveness of community engagement, (d) knowledge of health outcomes, and (e) demographics. The survey results demonstrated a disconnect in many instances where objective remedial improvements may not have resulted in improved environmental health perceptions in the community. The disconnect was most pronounced in the case of drinking water protection from mine waste and knowledge of health outcomes (cancer incidence rates and children's blood levels). The use of similar environmental health perception measurements may aid responsible agencies in monitoring for and addressing environmental health perception disconnects through better community engagement for the benefit of the impacted communities.

A comparison of respirable crystalline silica concentration measurements using a direct-on-filter Fourier transform infrared (FT-IR) transmission method vs. a traditional laboratory X-ray diffraction method.

Evaluation and control of respirable crystalline silica (RCS) exposures are critical components of an effective mine industrial hygiene program. To provide more timely exposure data in the field, an end-of-shift Fourier transform infrared (FT-IR) spectrometry method has been developed for evaluation of direct-on-filter RCS. The present study aimed to apply this FT-IR method using field samples collected in three Northwestern U.S. metal/nonmetal mines and compare the results to traditional laboratory X-ray diffraction analysis (XRD). Seventy-five dust samples were analyzed using both methods. Samples for each mine were split in half by random assignment, with half used to create a calibration factor for the FT-IR analysis and half used to apply the calibration. Nonparametric correlational and two-sample comparative tests were used to assess the strength of association and the level of agreement between the two methods. Strong, positive correlations were observed between FT-IR and XRD RCS concentrations, with Spearman rank correlation coefficients ranging between 0.84 and 0.97. The mean RCS concentrations determined through FT-IR analysis were lower than through XRD analysis, with mean differences ranging from -4 to -133 ug/m3 and mean percent errors ranging from 12% to 28%. There was a statistically significant improvement in the level of agreement between log FT-IR and log XRD RCS concentrations following calibration at two of the three mines, with mean differences of -0.03 (p = 0.002) and -0.02 (p = 0.044) in the log scale. The reduction in mean difference following calibration at the other mine was not statistically significant (mean log scale difference = -0.05, p = 0.215), but the differences between FT-IR and XRD were not significantly different without calibration (mean log scale difference = -0.07, p = 0.534). The results indicate that mine-specific calibration factors can improve the level of agreement between RCS concentrations determined via a field-based, end-of-shift FT-IR method in metal/non-metal mines as compared to traditional XRD analysis.

Noise characterization of oil and gas operations.

In cooperation with The Colorado Oil and Gas Conservation Commission, researchers at Colorado State University performed area noise monitoring at 23 oil and gas sites throughout Northern Colorado. The goals of this study were to: (1) measure and compare the noise levels for the different phases of oil and gas development sites; (2) evaluate the effectiveness of noise barriers; and (3) determine if noise levels exceeded the Colorado Oil and Gas Conservation Commission noise limits. The four phases of oil and gas development include drilling, hydraulic fracturing, completion and production. Noise measurements were collected using the A- and C-weighted sound scales. Octave band analysis was also performed to characterize the frequency spectra of the noise measurements. Noise measurements were collected using noise dosimeters and a hand-held sound-level meter at specified distances from the development sites in each cardinal direction. At 350 ft (107 m), drilling, hydraulic fracturing, and completion sites without noise barriers exceeded the maximum permissible noise levels for residential and commercial zones (55 dBA and 60 dBA, respectively). In addition, drilling and hydraulic fracturing sites with noise barriers exceeded the maximum permissible noise level for residential zones (55 dBA). However, during drilling, hydraulic fracturing, and completion operations, oil producers are allowed an exception to the noise permissible limits in that they only must comply with the industrial noise limit (80 dBA). It is stated in Rule 604.c.(2)A. that: "Operations involving pipeline or gas facility installation or maintenance, the use of a drilling rig, completion rig, workover rig, or stimulation is subject to the maximum permissible noise levels for industrial zones (80dBA)." [8] Production sites were within the Colorado Oil and Gas Conservation Commission permissible noise level criteria for all zones. At 350 ft (107 m) from the noise source, all drilling, hydraulic fracturing, and completion sites exceeded 65 dBC. Current noise wall mitigation strategies reduced noise levels in both the A- and C-weighted scale measurements. However, this reduction in noise was not sufficient to reduce the noise below the residential permissible noise level (55 dBA).

Comparing Occupational Health and Safety Management System Programming with Injury Rates in Poultry Production.

Effective methods to reduce work-related injuries and illnesses in animal production agriculture are sorely needed. One approach that may be helpful for agriculture producers is the adoption of occupational health and safety management systems. In this replication study, the authors compared the injury rates on 32 poultry growing operations with the level of occupational health and safety management system programming at each farm. Overall correlations between injury rates and programming level were determined, as were correlations between individual management system subcomponents to ascertain which parts might be the most useful for poultry producers. It was found that, in general, higher levels of occupational health and safety management system programming were associated with lower rates of workplace injuries and illnesses, and that Management Leadership was the system subcomponent with the strongest correlation. The strength and significance of the observed associations were greater on poultry farms with more complete management system assessments. These findings are similar to those from a previous study of the dairy production industry, suggesting that occupational health and safety management systems may hold promise as a comprehensive way for producers to improve occupational health and safety performance. Further research is needed to determine the effectiveness of such systems to reduce farm work injuries and illnesses. These results are timely given the increasing focus on occupational safety and health management systems.

Client Perceptions of Occupational Health and Safety Management System Assistance Provided by OSHA On-Site Consultation: Results of a Survey of Colorado Small Business Consultation Clients.

The Occupational Safety and Health Administration (OSHA) On-Site Consultation Service provides assistance establishing occupational health and safety management systems (OHSMS) to small businesses. The Safety and Health Program Assessment Worksheet (Revised OSHA Form 33) is the instrument used by consultants to assess an organization's OHSMS and provide feedback on how to improve a system. A survey was developed to determine the usefulness of the Revised OSHA Form 33 from the perspective of Colorado OSHA consultation clients. One hundred and seven clients who had received consultation services within a six-year period responded to the survey. The vast majority of respondents indicated that the Revised OSHA Form 33 accurately reflected their OHSMS and that information provided on the Revised OSHA Form 33 was helpful for improving their systems. Specific outcomes reported by the respondents included increased safety awareness, reduced injuries, and improved morale. The results indicate that the OHSMS assistance provided by OSHA consultation is beneficial for clients and that the Revised OSHA Form 33 can be an effective tool for assessing and communicating OHSMS results to business management. Detailed comments and suggestions provided on the Revised OSHA Form 33 are helpful for clients to improve their OHSMS.

Developing effective worker health and safety training materials: hazard awareness, identification, recognition, and control for the salon industry.

OBJECTIVE: In addition to formaldehyde, workers in salons can be exposed to other chemical irritants, sensitizers, carcinogens, reproductive hazards, infectious agents, ergonomic, and other physical hazards. Worker health and safety training is challenging because of current product labeling practices and the myriad of hazards portending risk for a wide variety of health effects. METHODS: Through a Susan B. Harwood Targeted Topic Training grant from the Occupational Safety and Health Administration and assistance from salon development and training partners, we developed, delivered, and validated a health and safety training program using an iterative five-pronged approach. RESULTS: The training was well received and resulted in knowledge gain, improved workplace safety practices, and increased communication about health and safety. CONCLUSIONS: These training materials are available for download from the Occupational Safety and Health Administration's Susan B. Harwood Training Grant Program Web site.

Occupational exposures to noise resulting from the workplace use of personal media players at a manufacturing facility.

This study examined the contribution of noise exposures from personal media player (PMP) use in the workplace to overall employee noise exposures at a Colorado manufacturing facility. A total of 24 workers' PMP and background noise exposures were measured. Twelve PMP users worked in high-background-noise exposure (HBNE) areas, and 12 worked in low-background-noise exposure (LBNE) areas. The self-selected PMP listening level of each worker was measured using an ear simulator, and the background noise of each employee workstation was measured using a sound level meter. Workers' self-reported PMP duration of use, PMP listening exposure levels, and background noise levels were used to estimate the daily occupational noise exposures. Measured background noise levels averaged 81 dBA for HBNE workers and 59 dBA for LBNE workers. Measured, free-field equivalent listening exposure levels were significantly greater for HBNE workers (85 dBA) compared with LBNE workers (75 dBA) (p = 0.0006). Estimated mean daily noise exposures for both groups were below the ACGIH threshold limit value for noise of 85 dBA8-hr time weighted average (TWA), specifically 84 dBA TWA for HBNE workers and 72 dBA TWA for LBNE workers. Three of 12 (25%) HBNE workers had estimated exposures greater than 85 dBA TWA when only background noise was considered, yet when PMP use was also considered, 6 of 12 (50%) had estimated exposures greater than 85 dBA TWA, suggesting that PMP use doubled the number of overexposed workers. None of the LBNE workers had estimated exposures greater than 85 dBA TWA. The contribution of PMP use to overall noise exposures was substantially less among HBNE workers than LBNE workers due to the disproportionate selection of noise-attenuating headsets among HBNE workers compared with LBNE workers. It is recommended that the facility management either restrict workplace PMP use among HBNE workers or require output-limiting technology to prevent occupational noise-induced hearing loss.