Eric J. Esswein

The utility of biological monitoring for manganese in ferroalloy smelter workers in South Africa.

Five hundred and nine workers at a manganese (Mn) smelting works comprising eight production facilities and 67 external controls were studied cross-sectionally. Exposure measures from personal sampling included inhalable dust, cumulative exposure indices (CEI) and average intensity (INT = CEI/years exposed) calculated for the current job at the smelter and also across all jobs held by subjects. Biological exposure was measured by Mn in the blood (MnB) and urine (MnU) and biological effect was measured by serum prolactin. Average lifetime exposure intensity across all jobs ranged from near 0 (0.06 microg/m3) for unexposed external referents to 5 mg/m3. Atmospheric exposures and MnB and MnU distributions were consistent with published data for both unexposed and smelter workers. Associations between biological exposures and groups defined by atmospheric exposures in the current job were substantial for MnB, less so for MnU and absent for serum prolactin. Random sampling of MnB measurements representative of a group of workers with more than 1-2 years of service in the same job and notionally homogenous exposure conditions could serve as a cross-sectional predictor of atmospheric Mn exposure in the current job, as well as for surveillance of Mn exposure trends over time. Correlations at the individual level were only modest for MnB (33% of the variance in log atmospheric Mn intensity in the current job was explained by log MnB), much worse for MnU (only 7%). However, a receiver operating characteristic (ROC) analysis was performed which showed that it is possible to use a MnB cut-off of 10 microg/l (the 95th percentile in the unexposed) to good effect as a screening tool to discriminate between individual exposures exceeding and falling below a relatively strict atmospheric Mn exposure threshold at the ACGIH threshold limit value (TLV) of 0.2 mg/m3. MnU has no utility as a measure of biological exposure nor does serum prolactin as a measure of biological effect.

Evaluation of Some Potential Chemical Exposure Risks During Flowback Operations in Unconventional Oil and Gas Extraction: Preliminary Results

Approximately 562,000 workers were employed in the U.S. oil and gas extraction industry in 2012; nearly half of those workers were employed by well servicing companies, which include companies that conduct hydraulic fracturing and flowback operations.(1) To understand possible risks for chemical exposures in modern oil and gas extraction operations, the National Institute for Occupational Safety and Health (NIOSH) initiated the Field Effort to Assess Chemical Exposures in Oil and Gas Workers.(2) Initial research identified exposure risks for respirable crystalline silica during hydraulic fracturing as an occupational health hazard.(3–5) This report describes industrial hygiene sampling during flowback operations at six unconventional oil and gas extraction sites in Colorado and Wyoming during spring and summer 2013. The results are considered preliminary; additional exposure assessments are needed to better understand the range of possible exposures, risk factors, and controls during flowback operations.

Exposures and health effects: An evaluation of workers at a sodium azide production plant

Sodium azide is the principal gas-generating agent used to inflate automobile supplemental restraint systems, more commonly called airbags. Although sodium azide is known to affect the cardiovascular system by causing peripheral vasodilation, there is no published literature describing occupational exposures to sodium azide in the rapidly growing automobile airbag industry. In 1994-1995, the National Institute for Occupational Safety and Health (NIOSH) conducted a cross-sectional study of health complaints reported by sodium azide production workers at the only continuous sodium azide production facility in the United States. The NIOSH evaluation consisted of a plant industrial hygiene survey, a symptom questionnaire, ambulatory blood pressure monitoring, and blood azide analysis. Personal breathing zone air monitoring revealed exposures to sodium azide and hydrazoic acid (a reactant product) at levels greater than the NIOSH Recommended Exposure Limits (RELs). In some cases, exposures exceeded the REL despite the use of air-supplied respirators. The questionnaire revealed that most workers reported headache (10 of 11 [91%]), episodes of low blood pressure (9 of 11 [82%]), and palpitations (8 of 11 [73%]) occurring in the production areas within the 6 months preceding the study. Mild headache (4 of 11 [36%]) was the only symptom reported during our 24-hr medical survey. Ambulatory blood pressure monitoring revealed one asymptomatic employee with a drop in blood pressure (defined as a drop in systolic [at least 20 mm Hg] and diastolic [at least 10 mm Hg] blood pressure) during a period of exposure to sodium azide at a level five times the NIOSH REL. Improvements in plant engineering controls, increased attention to employee hygiene practices, and a more comprehensive respiratory protection program were recommendations made by NIOSH to reduce exposures at the plant. All facilities handling sodium azide should be aware of the potential toxicity of sodium azide and hydrazoic acid.

Environmental and Occupational Health Response to SARS, Taiwan, 2003

Environmental and Occupational Health Industrial hygiene emergency response to SARS in Taiwan.

Handwipe Method for Removing Lead from Skin

Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) developed a handwipe removal method for lead (Pb) after field studies showed that workers in lead-acid battery plants had significant risks for dermal-oral lead exposures, despite their attempts to remove the lead by washing with soap and water. Hand washing with soap and water remains the standard recommendation for workers (as well as the public) to clean skin known or believed to be contaminated with toxic metals, such as lead. Despite longstanding recommendations for workers to “wash hands with soap and water,” no efficacy studies show this to be a completely effective removal method for lead. Removal of toxic metals such as lead from skin constitutes a decontamination procedure; it is not, in fact, a hand-washing step. NIOSH scientists conceived and developed a highly effective (nearly 100 %) method for removal of lead from skin. A systems approach was devised incorporating four components deemed necessary for effective metal removal: Surfaction, pH control, chelation, and mechanical effects. The handwipe removal method evolved from a previous NIOSH invention, the handwipe disclosing method for the presence of lead, in the interests of providing complementary techniques for dermal lead detection and decontamination. The method is a patented, award-winning, commercialized technology that has significant potential to prevent occupational and public exposures to lead.

Use of Direct Reading Surface Sampling Methods for Site Characterization and Remediation of Methamphetamine Contaminated Properties

Residual methamphetamine contamination in Clandestine laboratories represents a hazard to emergency response personnel, remediation workers and the general public. To address this threat, two rapid, sensitive surface sampling techniques to assess the location and level of methamphetamine contamination were developed. Both methods employ established industrial hygiene surface sampling materials (wipes and swabs) but differ in their sensitivity and detection technology. One method, based on colorimetric disclosure, detects and confirms a collected sample or visible residues. The second method uses a lateral flow immunochemical assay (LFIA) for semi-quantitative detection of trace contamination. The National Institute for Occupational Safety and Health (NIOSH) partnered with public health agencies to develop applications of the methods for assessment of methamphetamine contamination of suspected properties. These applications focused on safe strategies for site assessment, hazard characterization, and remediation effectiveness. To conduct the field studies, NIOSH researchers and their partners visited more than a dozen suspected laboratories including mobile labs, abandoned properties, occupied residences, and motel rooms. NIOSH found greater than 95% agreement between positive identification of the presence of methamphetamine by LFIA and laboratory-based, liquid chromatography mass spectroscopy (LC–MS) methods. Test results were used to develop site assessments and make personal protective equipment recommendations. Results were also used to conduct process-based decontamination of properties and to make health-based decisions on remediation, re-occupancy of residences, as well as determine the degree of contamination of personal property in an inactive clandestine laboratory. By partnering with stakeholders, NIOSH was able to achieve two primary goals: (1) to develop a level of awareness in health department sanitarians, law enforcement personnel and other first responders that methamphetamine surface contamination was a potentially significant route of exposure; (2) to validate our methods in the field and to develop protocols for proper use and interpretation of the results.

The development and testing of a prototype mini-baghouse to control the release of respirable crystalline silica from sand movers.

ABSTRACT Inhalation of respirable crystalline silica (RCS) is a significant risk to worker health during well completions operations (which include hydraulic fracturing) at conventional and unconventional oil and gas extraction sites. RCS is generated by pneumatic transfer of quartz-containing sand during hydraulic fracturing operations. National Institute for Occupational Safety and Health (NIOSH) researchers identified concentrations of RCS at hydraulic fracturing sites that exceed 10 times the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) and up to 50 times the NIOSH Recommended Exposure Limit (REL). NIOSH research identified at least seven point sources of dust release at contemporary oil and gas extraction sites where RCS aerosols were generated.  NIOSH researchers recommend the use of engineering controls wherever they can be implemented to limit the RCS released. A control developed to address one of the largest sources of RCS aerosol generation is the NIOSH mini-baghouse assembly, mounted on the thief hatches on top of the sand mover. This article details the results of a trial of the NIOSH mini-baghouse at a sand mine in Arkansas from November 18–21, 2013.  During the trial, area air samples were collected at 12 locations on and around a sand mover with and without the mini-baghouse control installed. Analytical results for respirable dust and RCS indicate the use of the mini-baghouse effectively reduced both respirable dust and RCS downwind of the thief hatches. Reduction of airborne respirable dust ranged from 85–98%; reductions in airborne RCS ranged from 79–99%. A bulk sample of dust collected by the baghouse assembly showed the likely presence of freshly fractured quartz, a particularly hazardous form of RCS.  Planned future design enhancements will increase the performance and durability of the mini-baghouse, including an improved bag clamp mechanism and upgraded filter fabric with a modified air-to-cloth ratio. Future trials are planned to determine additional respirable dust and RCS concentration reductions achieved through these design changes.

Measurement of area and personal breathing zone concentrations of diesel particulate matter (DPM) during oil and gas extraction operations, including hydraulic fracturing

ABSTRACT Diesel engines serve many purposes in modern oil and gas extraction activities. Diesel particulate matter (DPM) emitted from diesel engines is a complex aerosol that may cause adverse health effects depending on exposure dose and duration. This study reports on personal breathing zone (PBZ) and area measurements for DPM (expressed as elemental carbon) during oil and gas extraction operations including drilling, completions (which includes hydraulic fracturing), and servicing work. Researchers at the National Institute for Occupational Safety and Health (NIOSH) collected 104 full-shift air samples (49 PBZ and 55 area) in Colorado, North Dakota, Texas, and New Mexico during a four-year period from 2008–2012. The arithmetic mean (AM) of the full shift TWA PBZ samples was 10 µg/m3; measurements ranged from 0.1–52 µg/m3. The geometric mean (GM) for the PBZ samples was 7 µg/m3. The AM of the TWA area measurements was 17 µg/m3 and ranged from 0.1–68 µg/m3. The GM for the area measurements was 9.5 µg/m3. Differences between the GMs of the PBZ samples and area samples were not statistically different (P > 0.05). Neither the Occupational Safety and Health Administration (OSHA), NIOSH, nor the American Conference of Governmental Industrial Hygienists (ACGIH) have established occupational exposure limits (OEL) for DPM. However, the State of California, Department of Health Services lists a time-weighted average (TWA) OEL for DPM as elemental carbon (EC) exposure of 20 µg/m3. Five of 49 (10.2%) PBZ TWA measurements exceeded the 20 µg/m3 EC criterion. These measurements were collected on Sandmover and Transfer Belt (T-belt) Operators, Blender and Chemical Truck Operators, and Water Transfer Operators during hydraulic fracturing operations. Recommendations to minimize DPM exposures include elimination (locating diesel-driven pumps away from well sites), substitution, (use of alternative fuels), engineering controls using advanced emission control technologies, administrative controls (configuration of well sites), hazard communication, and worker training.

Evaluation of a Handwipe Disclosing Method for Lead

A qualitative chemical screening method for lead in wipe samples was evaluated for its utility in detecting the presence of lead in collected dust; preliminary evaluation of the performance of the method is reported here. In evaluating the method on pure lead compounds, the observed intensity of the characteristic color change due to the presence of lead was generally consistent with the relative solubilities of the tested compounds. Some pure (non-lead) metal compounds (e.g., those of Ag, Ba, Bi, Ca, Cd, Hg, and Sr) were found to give false positive results. Several representative lead-containing reference materials were also tested, and the qualitative test results differed for different materials. For materials collected on wipes, the method was found to be effective for detecting lead in several sample matrices commonly found in occupational settings. The technique was also applied on-site on dermal samples collected at field locations.

Workplace Simulations: An Alternative to On-Site Industrial Hygiene Sampling

Abstract Numerous hazardous agents are present in the workplaces of the construction industries. Conducting an on-site industrial hygiene survey in some phases of these industries can be difficult, if not impossible. An example is the evaluation of hazards arising in the cutting of epoxy-coated steel reinforcing rod (coated rod) in the structural steel erection industry (SIC 1791). When necessary, coated rod is cut using either a gasoline-powered cut-off saw or an oxy-acetylene cutting torch. Using either method generates smoke and dust that may be hazardous in their own right or that may contain hazardous materials such as combustion products of the epoxy resin coating. Typically, cutting coated rod is an unscheduled event that may have to be done quickly, as this phase of construction usually involves pouring large volumes of fresh (wet) concrete. It is not practical to anticipate such an event and to have industrial hygiene personnel and equipment standing by on-site to perform necessary industrial hyg...