Lead levels in new residential enamel paints in Taipei, Taiwan and comparison with those in mainland China.

Five brands of new enamel household paints from Taiwan were analyzed: two multi-nationals and three local. The median lead concentration of 2574 parts per million (ppm) dry weight was more than 30 times the current US standard of 90ppm for new paints and was more than 4 times the former standard of 600ppm. Lead levels ranged from below detection (4.5ppm) to 158,000ppm. Lead concentrations varied significantly by color of paint and paint brand but not by price per liter. Fifty-six percent of Taiwan paints had lead levels above the 90ppm US limit. One of the multi-national brands and two of the local brands had high levels of lead with the averages ranging from 12,890 to 53,640ppm. Concentrations were less than 90ppm in each of the samples from the other two brands. One of the two multi-national paint brands was imported as the house brand for its big box store in Taipei and had lead levels above 600ppm in four of five samples. Comparison of the lead concentrations of paints from Taiwan with those that we previously analyzed from mainland China revealed higher levels in Taiwan where the median level was 2574ppm compared to 46ppm in mainland China.

A field method for near real-time analysis of perchloroethylene in end-exhaled breath.

The field method for near real-time analysis of perchloroethylene (Perc) in breath is simple, fast, and reproducible for Perc breath analysis in field settings and should prove useful in industrial hygiene practice. The method allows Perc monitoring with good specificity to the sub-part per million (ppm) level within minutes of exposure. A commercially available, portable gas chromatograph with a photoionization detector was used in these analyses. Gas chromatograph settings were optimized in the laboratory for measurement of Perc in Tedlar bags. Laboratory development of the method included evaluation of the sensitivity, specificity, precision, and speed of analysis for Perc. Replicate aliquots of Perc at concentrations ranging from 0.01 to 100 ppm were used to construct a calibration curve. The mean retention time for Perc was 238 sec. The impact of potential interference by acetone, toluene, isoprene, methanol, ethanol, acetaldehyde, carbon tetrachloride, benzene, or chloroform was evaluated by mixing Perc with each compound and performing analyses. Measurements of Perc in human breath samples collected in Tedlar bags in a workplace setting were made and compared to measurements of the same samples made by an established analytical method using charcoal tubes (National Institute of Occupational Safety and Health [NIOSH] Method 1003). The accuracy, precision, and speed of the gas chromatograph method were determined. Measurements made with the new method were within a margin of +/- 8.8% (95% CI, n = 6) of measurements made according to NIOSH Method 1003 for field samples in the range of 0.9 to 6 ppm. Method precision was determined by calculating the pooled coefficient of variation for all measurements (replicates = 3) made in the field and was found to be 5.8%.

An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops.

Real-time monitoring was used to evaluate the ability of engineering control devices retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine that had a water-cooled condenser to reduce the air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls were successful at reducing the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent in the shop that had a refrigerated condenser installed on the dry-cleaning machine and 92 percent in the shop that had a carbon adsorber installed. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average (TWA) exposures were less dramatic. TWA exposures to perchloroethylene, as measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less. Differences between exposure results from real-time and conventional air sampling very likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. Although there were some difficulties and complications with installation and maintenance of the engineering controls, this study showed that retrofitting engineering controls may be a feasible option for some dry-cleaning shop owners to reduce worker exposures to perchloroethylene. By installing retrofit controls, a dry-cleaning facility can reduce exposures, in some cases dramatically, and bring operators into compliance with the Occupational Safety and Health Administration (OSHA) peak exposure limit of 300 ppm. Retrofit engineering controls are also likely to enable many dry-cleaning workers to lower their overall personal TWA exposures to perchloroethylene.

Effects of retrofit emission controls and work practices on perchloroethylene exposures in small dry-cleaning shops.

The effectiveness of commercially available interventions for reducing workers' perchloroethylene exposures in three small dry-cleaning shops was evaluated. Depending upon machine configuration, the intervention consisted of the addition of either a refrigerated condenser or a closed-loop carbon adsorber to the existing dry-cleaning machine. These relatively inexpensive (less than $5000) engineering controls were designed to reduce perchloroethylene emissions when dry-cleaning machine doors were opened for loading or unloading. Effectiveness of the interventions was judged by comparing pre- and postintervention perchloroethylene exposures using three types of measurements in each shop: (1) full-shift, personal breathing zone, air monitoring, (2) next-morning, end-exhaled worker breath concentrations of perchloroethylene, and (3) differences in the end-exhaled breath perchloroethylene concentrations before and after opening the dry-cleaning machine door. In general, measurements supported the hypothesis that machine operators' exposures to perchloroethylene can be reduced. However, work practices, especially maintenance practices, influenced exposures more than was originally anticipated. Only owners of dry-cleaning machines in good repair, with few leaks, should consider retrofitting them, and only after consultation with their machine's manufacturer. If machines are in poor condition, a new machine or alternative technology should be considered. Shop owners and employees should never circumvent safety features on dry-cleaning machines.