NIOSHTIC-2 Publications Search

A characterization of occupational exposures to crumb rubber modified asphalt and conventional (nonrubber containing) asphalt during road paving.

Burr-G; Miller-A
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :85
Between 1994 and 1997, seven health hazard evaluations were completed as part of an interagency agreement between the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Department of Transportation, Federal Highway Administration (FHWA). These surveys, performed in Michigan, Florida, Indiana, Arizona, northern and southern California, and Massachusetts to evaluate occupational exposures among asphalt paving workers, had the following objectives: (1) characterize occupational exposures to crumb rubber modified (CRM) asphalt and conventional (nonrubber containing) asphalt during road paving; (2) develop and field test new sampling and analytical methods; and (3) identify potential health effects associated with CRM asphalt and conventional asphalt exposures. This paper summarizes the occupational exposures measured during these surveys. At each site, full-shift personal breathing zone (PBZ) samples were collected on the paving crew (typically 6 to 10 workers) for total particulate, benzene soluble particulate, polycyclic aromatic compounds, and sulfur-containing compounds (induding benzothiazole, a sulfur-containing compound present in rubber tires). Benzothiazole was of interest since it may be useful as a surrogate indicator for other CRM asphalt fume exposures. Area samples were also collected over the screed auger and at background locations. Job tasks included paver, screed, and roller operators; rakers; and laborers; and all study participants were evaluated over 4 days (2 days with each type of asphalt paving). Samples were also collected for volatile organic compounds (VOCs), carbon monoxide (CO), hydrogen sulfide (H2S), sulfur dioxide (SO2), and ozone (O3). All PBZ air concentrations of asphalt fume were below the current NIOSH recommended exposure limit (REL) of 5 mg/m3 (measured as total particulate). The average exposures for paver, screed auger, and roller operators, although varying between sites and iob tasks, were generally higher during the CRM asphalt paving than during conventional asphalt paving, a trend that was also observed with the area air samples. Benzothiazole, as expected, was generally detected only during CRM asphalt paving. Concentrations of toluene, xylene, methyl isobutyl ketone, and benzene (analyzed because they were the most significant peaks in a qualitative scan of the asphalt fume) were typically less than 1 ppm, and total hydrocarbons, reported as Stoddard solvent, were well below the NIOSH REL of 350 mg/m3. Area concentrations of CO ranging up to 1000 ppm were measured where gasoline-powered equipment (such as vibrating tampers or portable generators) was in use, suggesting that some workers could be exposed to CO concentrations in excess of the NIOSH ceiling limit of 200 ppm. Concentrations of HS and SO2 were not detected, and O3 was present at background concentrations.
Construction-industry; Construction-workers; Construction-materials; Construction; Road-construction; Road-surfacing; Rubber-processing-equipment; Equipment-operators; Asphalt-cements; Asphalt-fumes; Asphalt-concretes; Employee-exposure; Sampling; Breathing-zone; Benzenes; Polycyclic-aromatic-hydrocarbons; Sulfur-compounds; Organic-compounds; Volatiles; Air-sampling; Exposure-assessment; Exposure-levels; Exposure-limits; Poison-gases
71-43-2; 95-16-9; 630-08-0; 7783-06-4; 7446-09-5; 10028-15-6; 108-88-3; 1330-20-7; 108-10-1; 8052-41-3
Publication Date
Document Type
Fiscal Year
NIOSH Division
Source Name
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division