Health hazard evaluation report: HETA-2005-0271-2996, Threemile Canyon Farms, Columbia River Dairy, Boardman, Oregon.
On June 14, 2005, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request for a health hazard evaluation (HHE) at Threemile Canyon Farms, Columbia River Dairy in Boardman, Oregon. The requestors reported health effects such as cough, sore throat, throat infection, burning eyes, dizziness, and headache and concerns about exposure to chemicals such as ammonia and hydrogen sulfide, and exposure to dust. During a site visit on August 9-11, 2005, we collected personal breathing zone (PBZ) and area air samples for ammonia and hydrogen sulfide using a combination of three direct reading methods. Additionally, we observed employee health practices and conducted confidential medical interviews on 56 randomly selected employees out of about 275 employees. Time-weighted average (TWA) concentrations of ammonia ranged from 2 to 8 parts per million (ppm), below the NIOSH recommended exposure limit (REL) of 35 ppm for a TWA up to 10 hours. Peak ammonia concentrations ranged from non-detectable to 9 ppm, below the NIOSH short-term exposure limit (STEL) of 35 ppm. Concentrations of hydrogen sulfide ranged from 1 to 2 ppm as a TWA. The two highest peaks, 10 ppm and 14 ppm, each lasted for one minute. These correspond to 10-minute average concentrations of 5.5 ppm and 6.1 ppm, below the NIOSH 10-minute ceiling limit of 10 ppm and the OSHA ceiling limit of 20 ppm. Although air sampling was not conducted for nuisance dust (particulates not otherwise regulated), trucks were observed spraying water on the dirt roads; this was a good attempt to reduce the amount of dust generated. In interviews, most employees thought their symptoms were related to road dust and that dust masks helped to reduce their symptoms. We also observed that some employees did not wear eye protection while pouring bleach solutions, reportedly because the safety glasses easily fogged. The most predominant symptom, burning/watery eyes, was reported by 23 of the 56 employees (41%). Thirteen people reported burning/itching of the throat (23%), eleven (20%) reported sneezing and ten (18%) burning/itching nose. Seven persons (12%) reported at least one episode of rash, five (9%) reported cough and excessive phlegm, and four (7%) complained of episodic chest tightness. Although there were two people with adult-onset asthma they did not associate their symptoms with the work environment. NIOSH investigators concluded that the ammonia, hydrogen sulfide, and dust levels measured or observed do not pose a health hazard. We identified a potential for chemical splash during the handling of bleach and recommended that face shields be made available to employees and that employees with potential for exposure be required to use them.