Survey report: control technology evaluation for controlling worker exposure to asphalt fumes from roofing kettles: kettle operated using low fuming asphalt at Toledo Correctional Institute, Toledo, Ohio, report no. CT-231-11b.
A survey was conducted on September 28 and November 5-8, 1999, at the Toledo Correctional Institute in Toledo, Ohio, where a new 3-ply roof with a coal-tar and gravel cap was being applied to a new correctional institute under construction. The engineering control used during this evaluation was low fuming asphalt. Other existing engineering controls for this industry will be evaluated during subsequent surveys. A final report will summarize the engineering controls evaluated from all of the surveys. In order to develop useful and practical recommendations, the ability of the engineering control measure to reduce worker exposure to air contaminants must be documented and evaluated. Where practical, this was accomplished by evaluating workers' exposure to asphalt fume particulate and PACs both with and without low fuming asphalt. Personal breathing zone and area air samples were collected and analyzed for total particulate (TP), benzene soluble fraction (BSF) of the total particulate using NIOSH Manual of Analytical Methods (NMAM) Method 5042, and NMAM Method 5800 for PACS. The temperature of the hot asphalt was recorded periodically with an electronic thermocouple and compared to the temperature gauge permanently mounted on the kettle. The results from this survey strongly suggest that both worker and area air exposures to TP, BSF, and total PAC were reduced when using low fuming asphalt when compared to conventional asphalt. Reductions were seen for TP, BSF, and total PAC for personal breathing zone samples for the kettle operator and for area air samples collected around the kettle and were for the most part statistically significant at 95% confidence. This was also true when the exposure data was standardized by the amount of asphalt used each day, when the data was adjusted to NTP, and when the data was adjusted to NTP and standardized. The results also show that the reduction is even greater for organic compounds (both BSF and PAC results) when compared to TP results. Reductions seen for TP, BSF, and total PAC for personal breathing zone samples for the roof-level workers were statistically significant at 95% confidence, but that was not the case for the reductions for the standardized exposure, NTP exposure, or NTP standardized exposure to TP and BSF. This would seem to indicate that the amount of asphalt used on a given day affects the degree of exposure for the roof-level workers. The major limitation of this study is the fact that only two days of sampling were conducted when conventional asphalt was used and two days of sampling were conducted when low fuming asphalt was used. Additional studies are needed to verify the trends seen here.