The purpose of this work by the Construction Occupational Health Program (COHP) is to improve air contaminant exposure assessment and to target interventions to reduce the silica exposures of heavy and highway construction workers. Exposure to silica is widespread in construction, as silica is a basic component of rock and sand, two common construction materials. Worker exposures result from chipping, grinding drilling, and sweeping of silica-containing materials like concrete and masonry products. Prolonged or intense exposures to respirable silica may cause silicosis, and recently, silica was designated a group I human carcinogen by IARC.
While grouping of workers by union or job performed usually provides a relatively effective method to estimate air concentration, COHP full-shift personal air sampling results indicate wide within union and job variation. For example, high variation in respirable silica exposures were found among laborers (geometric mean (GM)=26 ug/m3, geometric standard deviation (GSD)=5.9). Concrete finish (GM=61 ug/m3 GSD=5.9), and concrete demolition (GM=29 ug/m3 GSD=5.9) activities were also variable. Exposure modeling indicates differences can be attributed to the tool or machine, environmental conditions, and enclosure. Other factors are characterized by Time Varying Exposure Analysis (TVEA), a COHP developed method that helps account for exposure variability. TVEA indicates some important exposure determinants to be distance from source, time at dust-producing tasks, time in enclosure and number of sources.
This study demonstrates that construction silica exposures vary widely and that a comprehensive consideration of environmental and workplace exposure determinants is necessary for developing effective exposure controls.
Learning Objectives: At the conclusion of the session, the participant in this session will be able to: 1. Recognize that high exposure variability exists in construction. 2. List important factors affecting personal exposures to silica in construction. 3. Recognize the importance of a comprehensive approach to exposure assessment in the construction environment
Keywords: Occupational Exposure, Data Collection
Presenting author's disclosure statement:
Organization/institution whose products or services will be discussed: None
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.
The 128th Annual Meeting of APHA