Health hazard evaluation report: HETA-2003-0246-3013, Joint Pacific Marine Safety Code Committee, San Francisco, California.
On April 30, 2003, the National Institute for Occupational Safety and Health (NIOSH) received a request from the Joint Pacific Marine Safety Code Committee (JPMSCC) in San Francisco, California, to conduct a health hazard evaluation (HHE). The JPMSCC comprises members from the International Longshore and Warehouse Union (ILWU) and the Pacific Maritime Association (PMA). They were concerned about worker exposure to equipment-generated diesel exhaust during move/load/unload operations at marine terminals along the Pacific Coast. This report summarizes the evaluations at terminals in Long Beach and Oakland, California and Tacoma, Washington. NIOSH collected full-shift personal breathing zone (PBZ) and ambient area air samples for diesel exhaust (using elemental carbon [Ce] as a surrogate for exposure) and carbon monoxide (CO). Additionally, ambient airborne particulate matter concentrations and meteorological conditions were monitored. Voluntary confidential medical interviews with a physician were also conducted. Results from 168 air samples for Ce collected across 15 job titles ranged from 1.0 micrograms per cubic meter of air (µg/m3) to 42 µg/m3, and only six (4%) exceeded the California Department of Health Services, Hazard Evaluation System and Information Service (HESIS) recommended exposure limit of 20 µg/m3. When the data for PBZ samples were pooled and a mean exposure value calculated for each job title across all terminals, none of the job titles or ambient area air samples collected for Ce exceeded the HESIS exposure limit. However, the mean exposure for the Side Picker job title at Oakland did exceed the HESIS limit. While none of the 60 PBZ time-weighted average CO exposures exceeded occupational exposure criteria, some peak exposures did momentarily exceed the NIOSH ceiling limit of 200 parts per million (ppm). Results for the airborne particulate matter measurements indicate that some tasks, such as electric arc welding, street cleaning operations, and working near idling diesel engines increase particle concentrations above background levels. Interviewed workers reported symptoms consistent with exposure to diesel exhaust. Tasks such as working near idling diesel engines and installing/testing generator sets are associated with higher levels of diesel exhaust exposure and reported symptoms. NIOSH investigators conclude that a potential health hazard existed at the time of these surveys for workers in certain job titles. CO peak exposures occasionally exceeded the NIOSH REL of 200 ppm (Shop Men, Transtainer Mechanic, Side Picker). These peaks, however, mostly occurred during lunch and/or breaks and could be related to exposure to cigarette smoke. Symptoms reported by workers were consistent with exposure to diesel exhaust and tasks performed by workers in specific job titles (Shop Men working on running diesel engines) put them at risk of overexposure. Most diesel exhaust exposures, however, did not exceed the HESIS recommended exposure limit of 20 µg/m3. The exhaust system on Side Picker equipment should be directed away from the cab to reduce operator exposure to diesel exhaust, and Side Picker operators should keep the cab windows closed. If diesel engines are to be operated in the repair shop, exhaust ventilation should be improved to prevent the buildup of diesel exhaust within the shop. Shop Men should avoid exhaust pipes when working on running diesel engines, and use a flexible hose attached to the engine's exhaust pipe, routing the hose outdoors.