Hazardous exposures and engineering controls in the landscaping services industry.

Landscapers are exposed to noise, carbon monoxide (CO), respirable dust, and respirable crystalline silica (RCS) generated from the tools they use. Although engineering controls are available to reduce these exposures, no previous study has evaluated chronic exposures to landscapers in different work settings and compared exposures from landscaping tools with and without engineering controls. This field study of workers in the landscaping services industry documented the occupational exposures of 80 participants at 11 varied worksites to noise, CO, respirable dust, and RCS using personal breathing zone sampling. Results were analyzed using SAS/STAT 14.1. Analysis of variance was used for normally distributed data; otherwise, nonparametric methods were used. Most workers were overexposed to noise, with 94 of the 119 8-hr time-weighted average (TWA) noise exposures at or above the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL) of 85 dBA. There were no statistically significant differences among different locations or occupations. No 8-hr TWA exposures to CO above the NIOSH REL were measured. Overexposures to RCS were measured at all locations where hardscaping (installing or maintaining non-living aspects of the landscape) was taking place. This is the first known field study of this type to include hardscapers. The use of engineering controls such as dust capture or wet methods would reduce RCS exposures, but respiratory protection may still be needed. Task-based analysis of noise and CO exposure revealed that the loudest landscaping tools used in this study were hardscaping table saws, gas chainsaws, gas leaf blowers, chipper/shredders, gas string trimmers, and fuel mowers. Workers were exposed to significantly more noise and CO when using fuel-powered versions compared to battery-powered versions of leaf blowers, string trimmers, and chainsaws.