Do the National Institute for Occupational Safety and Health recommendations for working in the heat prevent excessive hyperthermia and body mass loss in unacclimatized males?

The National Institute for Occupational Safety and Health recommendations for work in the heat suggest workers consume 237 mL of water every 15-20 min and allow for continuous work at heavy intensities in hot environments up to 34 °C and 30% relative humidity. The goal was to determine whether the National Institute for Occupational Safety and Health recommendations prevented core temperature from exceeding 38.0 °C and greater than 2% body mass loss during heavy-intensity work in the heat. Eight males consumed 237 mL of water every 20 min during 2 hr of continuous heavy-intensity walking (6.4 kph, 1% grade) in a 34 °C/30% relative humidity environment, in accordance with the National Institute for Occupational Safety and Health recommendations. Projected core temperature and percent body mass loss were calculated for 4 and 8 hr of continuous work. Core temperature rose from baseline (36.8 ± 0.3 °C) to completion of 2 hr of work (38.1 ± 0.6 °C, p < 0.01), with two participants reaching the 38.0 °C threshold. Projected core temperatures remained elevated from baseline (p < 0.01), did not change from 2 to 4 hr (38.1 ± 0.7 °C, p > 0.99) and 4 to 8 hr (38.1 ± 0.8 °C, p > 0.99), respectively, and one participant exceeded 38.0 °C at 4 to 8 hr. There was no change in body mass loss over time (p > 0.99). During 2 hr of continuous heavy-intensity work in the heat, 75% of participants did not reach 38 °C core temperature and 88% did not reach 2% body mass loss when working to National Institute for Occupational Safety and Health recommendations.

Intermediary Perspectives on Total Worker Health in Small Businesses.

The future of work will include not only more small business employment, but also a need for greater consideration of more holistic approaches to addressing worker well-being. Previous research has suggested smaller firms need external assistance to add new or improve existing workplace health and safety activities. A Total Worker Health® (TWH) approach is potentially appealing to small employers as it is intended to identify and support comprehensive practices and policies that take into account the work environment (both physical and organizational) while also addressing the personal health risks of individuals, thus being more effective in preventing disease and promoting health and safety than each approach taken separately. NIOSH researchers applied the NIOSH Small Business Intervention Diffusion Model to conduct parallel community-based TWH activities in two geographically distinct communities in a large metropolitan area. Data were collected from intermediary organizations that work with or serve small businesses about their perceptions of the TWH approach as a potential service for them to offer small firms. Intermediary organizations engaged in implementation of TWH approaches with small businesses in the respective geographic areas for approximately one year. Results indicated intermediary organizations find value in providing TWH assistance to small employers, but several challenges for intermediaries implementing TWH among small employers remain.

Evaluation of total inward leakage for NIOSH-approved elastomeric half-facepiece, full-facepiece, and powered air-purifying respirators using sodium chloride and corn oil aerosols.

Recently, total inward leakage (TIL) for filtering facepiece and elastomeric half-mask respirators (EHRs) was measured according to the International Organization for Standardization (ISO) test method standard 16900-1:2014 that showed larger TIL for corn oil aerosol than for NaCl aerosol. Comparison of TIL measured for different aerosols for higher protection level respirators is lacking. The objective of this study was to determine TIL for EHRs, full-facepiece respirators, and loose-fitting and tight-fitting powered air-purifying respirators (PAPRs) using NaCl and corn oil aerosols to compare. TIL was measured for two models each of EHRs, full-facepiece respirators, and loose-fitting and tight-fitting PAPRs. After fit testing with a PortaCount (TSI, St. Paul, MN) using the Occupational Safety and Health Administration (OSHA) protocol, eight subjects were tested in the NaCl aerosol chamber first and then in the corn oil aerosol chamber, while another eight subjects tested in the reverse order. Subjects were randomly assigned to one of the two groups. TIL was measured as a ratio of mass-based aerosol concentrations inside the mask to the test chamber while the subjects performed ISO 16900-1-defined exercises using continuous sampling methods. The concentration of corn oil aerosol was measured with one light scattering photometer, alternately, and NaCl aerosol was measured using two flame photometers. Results showed the geometric mean TIL for EHR was significantly (p < 0.05) larger for corn oil aerosol than for NaCl aerosol. EHR models equipped with P100 filters showed relatively smaller TIL values than the same models with N95 filters showing that TIL was inversely related to filter efficiency. Interestingly, TIL was significantly (p < 0.05) larger for NaCl aerosol than for corn oil aerosol for PAPRs, but not for full-facepiece respirators. TIL was inversely related to fit factors of respirator types. Overall, filter efficiency and faceseal leakage determine TIL. The relative trends in TIL for the two aerosols' test methods differ between respirator types indicating that generalization of TIL for respirator types may not be appropriate when using different test agents.

Method for analyzing left-censored bioassay data in large cohort studies.

In retrospective epidemiological studies of large cohorts of workers exposed to radioactive materials, it is often necessary to analyze large numbers of bioassay data sets containing censored values, or values recorded as less than a detection limit. Censored bioassay data create problems for all bioassay analysis methods, including analytical techniques based on least-squares regression to estimate intakes. A method is presented here that uses a simple empirically-derived equation for imputing replacement values for urine uranium concentration results reported as zero or less than a detection limit, that produces minimal bias in intakes estimated using least-square regression methods with the assumption of lognormally distributed measurement errors.

Occupational exposures and chronic obstructive pulmonary disease (COPD): comparison of a COPD-specific job exposure matrix and expert-evaluated occupational exposures.

OBJECTIVES: To compare the occupational exposure levels assigned by our National Institute for Occupational Safety and Health chronic obstructive pulmonary disease-specific job exposure matrix (NIOSH COPD JEM) and by expert evaluation of detailed occupational information for various jobs held by members of an integrated health plan in the Northwest USA. METHODS: We analysed data from a prior study examining COPD and occupational exposures. Jobs were assigned exposure levels using 2 methods: (1) the COPD JEM and (2) expert evaluation. Agreement (Cohen's κ coefficients), sensitivity and specificity were calculated to compare exposure levels assigned by the 2 methods for 8 exposure categories. RESULTS: κ indicated slight to moderate agreement (0.19-0.51) between the 2 methods and was highest for organic dust and overall exposure. Sensitivity of the matrix ranged from 33.9% to 68.5% and was highest for sensitisers, diesel exhaust and overall exposure. Specificity ranged from 74.7% to 97.1% and was highest for fumes, organic dust and mineral dust. CONCLUSIONS: This COPD JEM was compared with exposures assigned by experts and offers a generalisable approach to assigning occupational exposure.

The Perils of Integrating Wellness and Safety and Health and the Possibility of a Worker-Oriented Alternative.

Integration of workplace wellness with safety and health has gained momentum on the initiative of the state allied with a segment of large employers and some health and safety professionals. Integration has a dual potential: to fundamentally reshape occupational health in ways that profoundly benefit workers, or to serve neoliberal corporate goals. A focus on the workplace and the ways work and health interact broaden the definition of a work-related injury or illness and emphasize and challenge the employer decisions that create hazards and determine risk. However, the implementation of integration is taking place in a context of corporate dominance and the aggressive pursuit of a neoliberal agenda. Consequently, in practice, integration efforts have emphasized individual worker responsibility for health and fail to actually integrate wellness with safety and health in a meaningful way. Can an alternative be envisioned and pursued that realizes the promise of integration for workers?

Development of an advanced respirator fit-test headform.

Improved respirator test headforms are needed to measure the fit of N95 filtering facepiece respirators (FFRs) for protection studies against viable airborne particles. A Static (i.e., non-moving, non-speaking) Advanced Headform (StAH) was developed for evaluating the fit of N95 FFRs. The StAH was developed based on the anthropometric dimensions of a digital headform reported by the National Institute for Occupational Safety and Health (NIOSH) and has a silicone polymer skin with defined local tissue thicknesses. Quantitative fit factor evaluations were performed on seven N95 FFR models of various sizes and designs. Donnings were performed with and without a pre-test leak checking method. For each method, four replicate FFR samples of each of the seven models were tested with two donnings per replicate, resulting in a total of 56 tests per donning method. Each fit factor evaluation was comprised of three 86-sec exercises: "Normal Breathing" (NB, 11.2 liters per min (lpm)), "Deep Breathing" (DB, 20.4 lpm), then NB again. A fit factor for each exercise and an overall test fit factor were obtained. Analysis of variance methods were used to identify statistical differences among fit factors (analyzed as logarithms) for different FFR models, exercises, and testing methods. For each FFR model and for each testing method, the NB and DB fit factor data were not significantly different (P > 0.05). Significant differences were seen in the overall exercise fit factor data for the two donning methods among all FFR models (pooled data) and in the overall exercise fit factor data for the two testing methods within certain models. Utilization of the leak checking method improved the rate of obtaining overall exercise fit factors ≥100. The FFR models, which are expected to achieve overall fit factors ≥ 100 on human subjects, achieved overall exercise fit factors ≥ 100 on the StAH. Further research is needed to evaluate the correlation of FFRs fitted on the StAH to FFRs fitted on people. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a file providing detailed information on the advanced head form design and fabrication process.].

Using the associative imagery technique in qualitative health research: the experiences of homecare workers and consumers.

The associative imagery technique is a qualitative tool with which researchers use carefully selected photographs or images to trigger participants' responses to explain difficult behavioral and social concepts. In this article, we describe the development and implementation of the associative imagery method in focus groups to understand the complex relationships between homecare workers and their clients as part of a larger health and safety intervention project conducted by the National Institute for Occupational Safety and Health. A total of 116 homecare workers and clients were recruited for the study. We found that participants used images mainly in two ways. First, the images served to remind participants of specific persons, events, and/or objects. Second, the images facilitated recollections and reflections that allowed participants to metaphorically describe their experiences, feelings, and emotions. Both usages of imagery generated comments that answered the research question in a more relevant, descriptive, and vivid way.

Performance of high flow rate samplers for respirable particle collection.

The American Conference of Governmental Industrial hygienists (ACGIH) lowered the threshold limit value (TLV) for respirable crystalline silica (RCS) exposure from 0.05 to 0.025 mg m(-3) in 2006. For a working environment with an airborne dust concentration near this lowered TLV, the sample collected with current standard respirable aerosol samplers might not provide enough RCS for quantitative analysis. Adopting high flow rate sampling devices for respirable dust containing silica may provide a sufficient amount of RCS to be above the limit of quantification even for samples collected for less than full shift. The performances of three high flow rate respirable samplers (CIP10-R, GK2.69, and FSP10) have been evaluated in this study. Eleven different sizes of monodisperse aerosols of ammonium fluorescein were generated with a vibrating orifice aerosol generator in a calm air chamber in order to determine the sampling efficiency of each sampler. Aluminum oxide particles generated by a fluidized bed aerosol generator were used to test (i) the uniformity of a modified calm air chamber, (ii) the effect of loading on the sampling efficiency, and (iii) the performance of dust collection compared to lower flow rate cyclones in common use in the USA (10-mm nylon and Higgins-Dewell cyclones). The coefficient of variation for eight simultaneous samples in the modified calm air chamber ranged from 1.9 to 6.1% for triplicate measures of three different aerosols. The 50% cutoff size ((50)d(ae)) of the high flow rate samplers operated at the flow rates recommended by manufacturers were determined as 4.7, 4.1, and 4.8 microm for CIP10-R, GK2.69, and FSP10, respectively. The mass concentration ratio of the high flow rate samplers to the low flow rate cyclones decreased with decreasing mass median aerodynamic diameter (MMAD) and high flow rate samplers collected more dust than low flow rate samplers by a range of 2-11 times based on gravimetric analysis. Dust loading inside the high flow rate samplers does not appear to affect the particle separation in either FSP10 or GK2.69. The high flow rate samplers overestimated compared to the International Standards Organization/Comité Européen de Normalisation/ACGIH respirable convention [up to 40% at large MMAD (27.5 microm)] and could provide overestimated exposure data with the current flow rates. However, both cyclones appeared to be able to provide relatively unbiased assessments of RCS when their flow rates were adjusted.

Effects of risk-focused and recommendation-focused mental imagery on occupational risk communication.

This study examined the impact of mental imagery instructions in a National Institute for Occupational Safety and Health (NIOSH) safety document conveying risk and safety information to farmers. A sample of 314 farmers recruited from a large Southeastern state fair was randomly assigned to conditions in a 2 x 2 design. Participants received a NIOSH safety document about skid steer loader safety in which 2 types of mental imagery instructions were manipulated: (a) risk-focused (imagery vs. control) and (b) recommendation-focused (imagery vs. control). Results indicate that risk-focused imagery influenced perceptions of susceptibility to workplace accidents, whereas recommendation-focused imagery influenced attitudes toward engaging in safety behaviors, intentions to share safety information with others, and perceptions of the safety message. Further analyses indicated that ease of imagery partially mediated the relationship between the imagery manipulations and these outcomes. Other potential mechanisms for these effects are discussed.

The rise and fall of occupational medicine in the United States.

Thirty years ago, occupational medicine was one of the smallest of all the medical specialties, ignored by most physicians and medical schools. Occupational physicians were more likely to have entered the field through career transition than by residency training. In 1970, governmental agencies sought to transform occupational medicine into a major clinical specialty. Influential groups projected a need for large numbers of physicians in the field. Residency training was expanded, as were other teaching programs. However, industry and its workers' compensation insurance partners were not widely included in these plans. For that reason, among others, many physicians entering the field met with disappointment. About half the corporate positions for occupational physicians have disappeared in the last decade. Private practice opportunities turned out to be much more limited than planners had anticipated. Attempts to bring occupational medicine into the curriculum of the medical schools failed. Many of the residency programs that had been created are now closing. The proposal that occupational medicine create a joint specialty with environmental medicine is not widely accepted by the rest of medicine. Because so few physicians obtain board certification, it appears that the specialty of occupational medicine is returning to its former obscurity.

[Musculoskeletal disorders caused by repetitive trauma of the upper limbs: a paradigm of the development of occupational diseases and industrial medicine]. / I "disturbi" muscolo scheletrici da traumi ripetuti agli arti superiori: paradigma della evoluzione delle patologie da lavoro e della Medicina del Lavoro.

The work related musculoskeletal disorders (WMSDs) are a wide range of inflammatory and degenerative disease and disorders that result in pain and functional impairment. All available definitions for WMSDS are non consistent and require in each individual case and in each group study careful identification of symptoms, signs and findings. WMSDs, as a mutifactorial work related disease, are associated to physical and psychosocial factors at work and other individual, sociocultural factors. They are therefore good paradigm for the changing occupational risks and illness and for the new methods that the occupational medicine and the preventive disciplines have to set up. The research and standardization needs appear to be more evident for framing pathogenesis, biological response and pathology of WMSDs and mainly for risk factors assessment, since suitable analytical methods are still not available. The agreement of valid standardised methods (guide lines) for the evaluation of working conditions and assessment of risk factors is required, taking due regard to the multidisciplinary approach both in biological and medical areas and in poly technical ones. Finally attention would be paid to the strategy for prevention, implementing ergonomic programmes, health surveillance, adequate training to work, aimed to primary prevention of WMSDs.

Developing occupational and environmental medicine curricula for primary care residents: project EPOCH-Envi. Educating Physicians in OCupational Health and the Environment.

To help primary care residency programs develop or improve residency curricula in occupational and environmental medicine, the National Institute for Occupational Safety and Health launched a train-the-trainer initiative. This project was called EPOCH-Envi (Educating Physicians in OCcupational Health and the Environment). From 1990 to 1996, 46 2-day curriculum development workshops were held. These featured (1) guidelines on how to plan, implement, and evaluate a curriculum, (2) continuing education on occupational illnesses and injuries, (3) a worksite or environmental site visit, and (4) information resources. A total of 435 faculty from 305 residency programs participated, representing 42.5% of the family practice residencies and 24.9% of the internal medicine residencies in the United States. A survey conducted among attendees (60.4% response rate) 17 months after their workshop revealed that 65.6% of respondents had added lectures on occupational and environmental topics to the residency curriculum. Other curriculum improvements were also made. Primary care physicians manage most patients with occupational and environmental health problems or concerns. Providing technical assistance specifically designed to support occupational and environmental health education in primary care residencies can have a positive impact on curriculum content.

A hybrid likelihood algorithm for risk modelling.

The risk of radiation-induced cancer is assessed through the follow-up of large cohorts, such as atomic bomb survivors or underground miners who have been occupationally exposed to radon and its decay products. The models relate to the dose, age and time dependence of the excess tumour rates, and they contain parameters that are estimated in terms of maximum likelihood computations. The computations are performed with the software package EPI-CURE, which contains the two main options of person-by person regression or of Poisson regression with grouped data. The Poisson regression is most frequently employed, but there are certain models that require an excessive number of cells when grouped data are used. One example involves computations that account explicitly for the temporal distribution of continuous exposures, as they occur with underground miners. In past work such models had to be approximated, but it is shown here that they can be treated explicitly in a suitably reformulated person-by person computation of the likelihood. The algorithm uses the familiar partitioning of the log-likelihood into two terms, L1 and L0. The first term, L1, represents the contribution of the 'events' (tumours). It needs to be evaluated in the usual way, but constitutes no computational problem. The second term, L0, represents the event-free periods of observation. It is, in its usual form, unmanageable for large cohorts. However, it can be reduced to a simple form, in which the number of computational steps is independent of cohort size. The method requires less computing time and computer memory, but more importantly it leads to more stable numerical results by obviating the need for grouping the data. The algorithm may be most relevant to radiation risk modelling, but it can facilitate the modelling of failure-time data in general.

The effects of various dental procedures and patient behaviors upon nitrous oxide scavenger effectiveness.

This prospective study of 36 children, ages 44-93 months, receiving nitrous oxide-oxygen under standardized conditions during routine dental procedures was conducted to determine what influence eight selected dental procedures and three patient behaviors had on ambient nitrous oxide (N2O) levels in the dentist's breathing zone. Half the children received nitrous oxide-oxygen via a scavenging nasal mask. An infrared spectrophotometer analyzed the ambient N2O level continuously throughout the procedure and the time-weighted average (TWA) for consecutive 15-sec intervals was recorded by a microprocessor. A video camera was used to synchronize the coded dental procedures and patient behaviors to the TWA ambient N2O levels recorded. The results demonstrated that scavenging significantly reduced the dentist's exposure to ambient N2O (P less than 0.05, nonscavenged mean = 284.7 ppm; scavenged mean = 36.6 ppm), but the mean TWA N2O concentration remained significantly higher, P less than 0.05, than the 25-ppm level recommended by the National Institute for Occupational Safety and Health (NIOSH). Supplemental oral evacuation was the only dental procedure capable of reducing ambient N2O to below NIOSH's recommendation when scavenging was employed. The administration of local anesthesia consistently created a significant increase in ambient N2O levels. Patient behaviors of talking, crying, and movement also resulted in significant increases from baseline ambient N2O levels.