Hydrocarbons (HCs) found in fuels and solvents are ubiquitous in the environment, yet we know little about their effects on the endocrine system. The objective of this study was to assess the potential reproductive endocrine effects of low-dose HCs encountered by female U.S. Air Force personnel with fuel (primarily JP-8 jet fuel) and solvent exposures (n = 63). We estimated the internal dose of HCs in fuels and solvents by measuring their levels in exhaled breath, including the sum of aliphatic HCs (C6H14-C16H34) and the sum of aromatic HCs (benzene, ethylbenzene, toluene, and m,p,o-xylenes). Adverse outcome measures included urinary endocrine markers that have been associated with nonconceptive (vs. conceptive) menstrual cycles in ovulatory women: lower preovulatory luteinizing hormone (LH) and mid-luteal phase pregnanediol 3-glucuronide (Pd3G) and estrone 3-glucuronide, and higher follicle phase Pd3G. We also obtained reproductive and exposure information from baseline questionnaires and daily diaries. Toluene was the most frequently found analyte in the breath, with values up to 52.0 ppb, and benzene breath levels were up to 97.5 ppb. Regression analysis revealed that preovulatory LH levels were significantly lower (p = 0.007) among women whose total aliphatic HC levels were above the median. The relationship between elevated aliphatic HC exposure and lowered preovulatory LH levels in the present study suggests that compounds in fuels and some solvents may act as reproductive endocrine disruptors. Confirmation of these findings is needed, not only to determine if fuel and solvent exposure may impact other LH-dependent physiologic functions but also to examine effects of fuels and solvents on conception.

Video exposure assessments were conducted in a comparative anatomy laboratory using formaldehyde-preserved sharks and cats. Work in the facility using time-integrated samplers indicated personal and area concentrations generally below the current OSHA permissible exposure limit. However, complaints about room air quality were frequent and routine. Using a photoionization detector with an integral data logger, total ionizables present were sampled as a surrogate for formaldehyde. After synchronizing time tracks from the datalogger concentrations with simultaneously created videotapes of laboratory tasks, composite video exposure overlays were generated. Use of this video exposure method revealed very short-lived, excessively high peak exposure events, whereas conventional time-weighted averages indicated the majority (30/32) of personal exposures were below the OSHA limit of 0.75 ppm. These legally acceptable exposure levels were associated with self-reported symptoms of burning nose and eyes and eye irritation. Thus, transient peak formaldehyde concentrations not detected by longer term averaging studies could be responsible for the health effects reported. The video exposure monitoring method demonstrated that close dissection work, opening peritoneal cavities, and specimen selection activities were most likely the causes of elevated student exposures. Teaching assistants' exposures were the highest, exceeding OSHA limits on several occasions. The utility of the video monitoring method for conducting enhanced, critical task exposure assessments is discussed.

Mercuric chloride has been used for control of insect and fungal infestations in herbarium collections for over two centuries. One of the lasting effects of this use is the long­term evolution of elemental mercury vapor from treated specimens. The vapor can contaminate untreated specimens sharing the same closed environment and can pose a human health hazard. By modifying the technique for use of a commercially available mercury indicating powder (Mallinckrodt Baker, Inc., J. T. Baker Mercury Indicator) it is possible to create an inexpensive and fairly rapid test for mercury vapor in herbarium cabinets. The indicator is mixed with deionized water and applied to glass microscope slides. One or more slides are placed inside a cabinet and any color change in the indicator is compared to unexposed controls. In the authors’ experiments, the indicator results were compared against readings taken using a Jerome 431­X Mercury Vapor Analyzer and a Lumex RA­915+ Multifunctional Mercury Analyzer and were found to be broadly related to the concentration of mercury vapor present in each cabinet. The method can be used to check for mercury contamination in incoming shipments of specimens and to identify cabinets that currently contain or formerly contained contaminated specimens. Practical safety guidelines have been developed for accessing cabinets that give a positive test for the vapor and for handling contaminated specimens.

At a machining center used to produce transaxle and transmission parts, aerosol instrumentation was used to quantitatively evaluate size-dependent mist generation of a synthetic metalworking fluid (MWF) consisting primarily of water and triethanolamine (TEA). This information was used to select an air cleaner for controlling the mist. During most machining operations, the MWF was flooded over the part. These machining operations were performed in a nearly complete enclosure that was exhausted to an air cleaner consisting of three sections: a fall-out chamber, a trifilter section to capture metal chips and mist, and a 1.13 m3/sec (2400 ft3/min) blower. The partnering company requested that National Institute for Occupational Safety and Health (NIOSH) researchers perform an evaluation of the effectiveness of a commercially available air cleaner. After NIOSH researchers characterized mist generation at the machining centers and found that performance of a test air cleaner appeared to be suitable, the company installed more than 25 air cleaners on different machining centers in this plant and enclosed the corresponding fluid filtration unit. The facility also has implemented a maintenance program for the air cleaners that involves regularly scheduled filter changes; performance is ensured by monitoring static pressure. A NIOSH-conducted air sampling evaluation showed that area TEA concentrations were reduced from a geometric mean of 0.25 to 0.03 mg/m3. Personal total particulate concentrations were reduced from a geometric mean of 0.22 to 0.06 mg/m3. These results show the effectiveness of this combination of enclosure, ventilation, and filtration to greatly reduce the exposure to MWF mist generated in modern machining centers.

Effective, economical control of metalworking fluid mists at the source is important, because exposure to these mists may cause adverse health effects. This study investigated performance changes over time for industrial collectors that removed metalworking fluid mist in the laboratory and in a transmission plant. Aerosizers were used to measure the efficiency of each stage in several multistage collectors as a function of mist droplet diameter, for up to one year of continuous operation. Metal-mesh, first-stage filters operated at low pressure drops and were effective at removing droplets larger than 3 to 5 microns in diameter. Some second-stage filters worked better than others. Both "65 percent" and "95 percent" cartridge filters failed after only a few weeks; their efficiencies decreased substantially over that time. Pocket filters and cylindrical cartridges used as second-stage filters also decreased in efficiency for submicron droplets. Whereas filters for solid particles load continuously to form a dust cake that increases efficiency, mist filters form no cake and load only to the point where collection equals drainage. As a mist filter loads, the interstitial gas velocity increases, so that efficiency decreases for small droplets that collect by diffusion. Although a third-stage 95 percent DOP filter showed important decreases in efficiency over time for submicron droplets, third-stage HEPA filters operated with efficiencies that consistently approaches 100 percent for droplets of all sizes, even after one year of operation. These results suggest that the performance of second-stage filters can be improved if they can be made to drain collected liquid more effectively. For high efficiency, mist collectors should use a HEPA filter as a final stage.