MDI concentrations during application of spray-on truck bed-liners.
Almaguer D; Streicher R; Burroughs G; Ernst M; Kovein R; Shulman S
American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 2004 May; :74
A study was conducted to evaluate potential worker exposures to 4,4'-diphenylmethane diisocyante (MDI) during the application of spray-on truck bed-liners. The Washington State Department of Labor and Industry recently observed MDI exposures in this industry and expressed concerns to NIOSH about excessive occupational asthma claims. The spray-on bed-liner industry is rapidly growing and dominated by small business entities. It has been estimated there are approximately 3000 bed-liner shops in the U.S. The process is analogous to undercoating and involves the application of an aerosolized two-part polyurethane or polyurea coating to the surface and walls of pick-up truck beds to provide a protective non-skid coating. Part A is a polymeric diisocyanate with varying percentages of MDI monomer, MDI prepolymer, and polymeric MDI. Part B is a polyol resin that reacts with the diisocyanate. The two components are pumped to a spray gun mixing chamber and sprayed at sufficient velocity to cause atomization. MDI samples were collected at six spray-on bed-liner facilities to determine MDI concentrations within the spray booths and adjacent areas. Samples were collected at a flow rate of 1 liter per minute (lpm) according to NIOSH Method #5525. The sampling train consisted of an impinger containing a solution of 1-(9-anthracenylmethyl)piperazine (MAP) reagent in butyl benzoate followed by a 37-mm two-piece filter cassette containing a glass fiber filter impregnated with solid MAP. Preliminary results indicate that MDI concentrations within the facilities ranged from non-detectable to 5.2 mg/m3, some exceeding the OSHA ceiling limit of 0.2 mg/m3. Applicators wore supplied-air respirators. These results show that ventilation must be improved before allowing relaxation of personal protective equipment requirements.
Occupational-exposure; Trucking; Bronchial-asthma; Aerosols; Spraying-equipment; Sampling; Personal-protective-equipment; Ventilation; Control-technology; Engineering-controls; Exhaust-ventilation; Exposure-levels; Polymers; Work-practices; Workplace-studies; Respiratory-protection; Urethanes; Coatings
Research Tools and Approaches: Control Technology and Personal Protective Equipment
American Industrial Hygiene Conference and Exposition, May 8-13, 2004, Atlanta, Georgia