Health Hazard Evaluations (HHEs)

(2005) Kewaunee Fabrications, LLC, Kewaunee, Wisconsin. (Click to open report)
On September 3, 2004, the National Institute for Occupational Safety and Health (NIOSH) received a health hazard evaluation (HHE) request from the management at Kewaunee Fabrications, LLC, Kewaunee, Wisconsin. The request asked NIOSH to evaluate employee exposures to hexamethylene diisocyanate (HDI) during spray painting. Additionally, exposure to volatile organic compounds (VOCs), particulates, and silica was measured. Two ventilation systems were examined and confidential medical interviews wi... (Click to show more) On September 3, 2004, the National Institute for Occupational Safety and Health (NIOSH) received a health hazard evaluation (HHE) request from the management at Kewaunee Fabrications, LLC, Kewaunee, Wisconsin. The request asked NIOSH to evaluate employee exposures to hexamethylene diisocyanate (HDI) during spray painting. Additionally, exposure to volatile organic compounds (VOCs), particulates, and silica was measured. Two ventilation systems were examined and confidential medical interviews with 13 employees were performed. Full-shift air samples for HDI, VOCs, particulates, and silica were collected between December 13-15, 2004. No air samples collected for HDI monomer exceeded the NIOSH Recommended Exposure Limit (REL) of 35 micrograms per cubic meter (microg/m3). There is no Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for HDI monomer or other species of HDI. However, the United Kingdom Health and Safety Executive (UK-HSE) does publish a Total Reactive Isocyanate Group (TRIG) 8-hour time-weighted average (TWA) criteria of 20 microg/m3 and a Ceiling Limit criteria of 70 microg/m3. Of the 15 painters sampled for HDI exposure, six workers' had PBZ levels that exceeded the UK-HSE TRIG 8-hour TWA criteria of 20 microg/m3 while four workers' HDI levels exceeded the UK-HSE TRIG Ceiling Limit criteria of 70 microg/m3. Workers wore supplied air respirators, full-body Tyvek suits, boot covers, and latex gloves while spray painting, so actual exposure to airborne HDI may be lower. However, latex gloves do not provide adequate protection against HDI and other solvents used in the paint shops. Two sanding/prep workers' particulate exposure levels exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV), (10 milligrams per cubic meter of air [mg/m3]). Levels for another worker engaged in the same activity also exceeded the OSHA PEL of 15 mg/m3. No silica (quartz and cristobalite) was found in these samples. Disposable filtering-facepiece respirators were available on a voluntary basis and sporadically used by some workers engaged in sanding/prep activities. All samples collected for VOCs were well below relevant occupational exposure criteria. Air velocities, measured at the exhaust outlets, were three to seven times higher in the West paint shop than in the East paint shop. This likely accounted for the lower airborne concentration of HDI in the West paint shop. No consistent respiratory symptoms were noted among the 13 workers interviewed, and symptoms reported were not those commonly found among workers exposed to HDI. However, a common work practice reported by workers involved the use of methyl ethyl ketone (MEK) to wash their skin and remove paint. This practice should be discontinued because MEK can be absorbed through the skin. NIOSH investigators conclude that a health hazard exists from exposure to particulates during the sanding/prep work activity and the use of solvents such as MEK to clean skin. Recommendations to increase the level of protection for workers engaged in sanding/prep activities include mandatory use of NIOSH-approved, single-use filtering-face piece N-95 respirators. Additionally, exhaust ventilation in the East paint shop should be increased to at least 100 feet per minute (fpm), as an average air velocity across the exhaust outlet to reduce the potential health hazard from exposure to isocyanates. (Click to show less)
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(2005) Metropolitan Transit Authority of New York City, New York City, New York. (Click to open report)
In January 2002, the National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation (HHE) of the Metropolitan Transit Authority, New York City Transit (MTA-NYCT) from representatives of the Transport Workers Union (TWU), Local 100. The Amalgamated Transit Union (ATU), Local 726, later asked to be included in this HHE. The HHE request cited concerns about respiratory and mental health symptoms among MTA employees subsequent to the September 11 Worl... (Click to show more) In January 2002, the National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation (HHE) of the Metropolitan Transit Authority, New York City Transit (MTA-NYCT) from representatives of the Transport Workers Union (TWU), Local 100. The Amalgamated Transit Union (ATU), Local 726, later asked to be included in this HHE. The HHE request cited concerns about respiratory and mental health symptoms among MTA employees subsequent to the September 11 World Trade Center (WTC) attack. Employees believed exposure to the World Trade Center (WTC) attacks caused these symptoms. In response, NIOSH investigators conducted meetings between MTA-NYCT management and union representatives to prepare for a study to evaluate worker concerns. The initial site visit included an opening conference, a walk-through evaluation of three subway train stations near the WTC, and a closing conference. During the week of April 30, 2002, NIOSH investigators administered questionnaires to 269 MTA employees. This self-administered questionnaire contained questions about demographics, past medical history, smoking history, work duties and location, WTC-related activities performed, and symptoms occurring on and after September 11. Questionnaire data analysis showed that workers in the dust cloud at the time of the WTC collapse had significantly higher risk of persistent lower respiratory symptoms (OR=9.85; 95% CI: 2.24, 58.93), persistent mucous membrane symptoms (OR=4.91; 95% CI: 1.53, 16.22), depressive symptoms (OR=2.48; 95% CI: 1.12, 5.51), and Post Traumatic Stress Disorder (PTSD) symptoms (OR=2.91; 95% CI: 1.003, 8.16) compared to those not exposed to the dust cloud. Based on these data, we conclude that clinical follow up for physical and psychological health conditions should be provided for affected public transportation workers subsequent to a catastrophic event. NIOSH sent an interim letter including preliminary results to MTA and union officials on December 17, 2002. This report describes our final results, analyses, conclusions, and recommendations. NIOSH investigators determined that NYC transit workers exposed to the dust cloud at the time of the September 11, 2001, WTC collapse had significantly higher risk of persistent lower respiratory and mucous membrane symptoms, and depressive and PTSD symptoms 7-1/2 months later compared to those not exposed to the dust cloud. Clinical follow up of affected transit workers for physical and psychological conditions should be continued through existing federal programs. Worker participation in these programs should be encouraged by MTA management. (Click to show less)
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(2005) Taft Elementary School, Santa Ana, California. (Click to open report)
On February 1, 2005, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request for a health hazard evaluation (HHE) at the Taft Elementary School in the Santa Ana Unified School District (SAUSD) in Santa Ana, California. The requesters were concerned about exposure to "toxic mold" in the school. There were reports that teachers had been diagnosed with toxic encephalopathy (brain damage) while other complaints included migraine headaches, sinusitis... (Click to show more) On February 1, 2005, the National Institute for Occupational Safety and Health (NIOSH) received a confidential employee request for a health hazard evaluation (HHE) at the Taft Elementary School in the Santa Ana Unified School District (SAUSD) in Santa Ana, California. The requesters were concerned about exposure to "toxic mold" in the school. There were reports that teachers had been diagnosed with toxic encephalopathy (brain damage) while other complaints included migraine headaches, sinusitis, asthma and other health conditions related to toxic mold exposure in the school. A site visit was made on April 5-6, 2005, which included an opening conference, an inspection of the school, and confidential employee interviews. A closing conference was held in which preliminary findings and recommendations were presented. Measurements of indoor environmental quality were made including temperature, relative humidity, and carbon dioxide; and a moisture meter was used to detect moisture in walls and ceilings or wherever evidence of water staining was visible in the buildings. Visual inspections were made on each of the five 30-ton multizone heating, ventilation, and air conditioning (HVAC) units and on 6 of the 12 Trane (3-ton) air handling units (AHUs). To investigate the nature of fine black particulates on filters installed downstream of the central AHUs, samples of air filters were collected and evaluated using scanning electron microscopy. Indoor temperature, relative humidity (RH), and carbon dioxide (CO2) in buildings A and B ranged from 70 degrees-77 degrees, 25%-38% and 569-1060 ppm, respectively. Indoor temperature, RH and CO2 in bungalows B-3, B-4, and B-9 ranged from 72 degrees-79 degrees, 41%-58% and 1374-1477 ppm, respectively. Outside measurements were 76 degrees-77 degrees, 23% and 443-450 ppm. The presence of moisture was not detected on or in walls, ceiling tiles or wood framing members where evidence of previous water staining was visible. Microscopy results from air filters revealed various mineral fragments, skin cells, pollen and mold spores, and diesel particulates. Other reported particulates appeared physically similar to rubber dust. Minor deficiencies were found in several AHUs. Fifteen of the 37 (41%) staff members interviewed reported no symptoms related to work. The most common work-related symptoms were nasal symptoms such as runny or stuffy nose (8/37 or 22%). Work-related eye irritation was reported by four persons (11%). Headache, throat irritation, and cough were each reported by three (8%). Two persons described sinus pressure that got better when away from work. Nobody reported shortness of breath, chest tightness, or wheezing. Eight of 37 (22%) reported constant sinus problems or recurrent sinusitis. Three persons reported memory problems and being diagnosed by the same physician with toxic encephalopathy from mold exposure in the school. Medical records were also reviewed for seven persons. One person had evidence of sinusitis and rhinitis and one had rhinitis. None had evidence of toxic encephalopathy. NIOSH investigators did not identify an occupational health hazard at the Taft Elementary School. Inspection of the HVAC system revealed minor problems such as evidence of dust intrusion, and presence of standing water and biofilm in some of the condensate drain pans. All water leaks had been repaired, and there was no evidence of mold or fungal growth. Taft employees had rates of work-related nasal problems similar to those reported in studies of buildings with indoor environmental quality complaints; however, we were unable to directly relate any symptom to the work environment. No exposure was identified in the school that would cause toxic encephalopathy, and there was sufficient evidence to conclude that none of the Taft Elementary School employees interviewed had toxic encephalopathy. Recommendations are included in this report to address HVAC deficiencies in all units that were inspected. (Click to show less)
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(2005) U.S. Department of Transportation, St. Lawrence Seaway Development Corporation, Massena, New York. (Click to open report)
In October 2001, the National Institute for Occupational Safety and Health (NIOSH) received a joint labor/management request to conduct a health hazard evaluation (HHE) at the Dwight D. Eisenhower and Bertrand H. Snell Locks on the St. Lawrence Seaway, near Massena, New York. The request described "flu-like symptoms" and "general ill health" as concerns among workers exposed to stagnant water and decaying marine life during the annual winter inspection, cleaning, and repairs of the locks. Anothe... (Click to show more) In October 2001, the National Institute for Occupational Safety and Health (NIOSH) received a joint labor/management request to conduct a health hazard evaluation (HHE) at the Dwight D. Eisenhower and Bertrand H. Snell Locks on the St. Lawrence Seaway, near Massena, New York. The request described "flu-like symptoms" and "general ill health" as concerns among workers exposed to stagnant water and decaying marine life during the annual winter inspection, cleaning, and repairs of the locks. Another impetus for the request was the collapse of one worker at the bottom of a lock during the previous winter. During site visits in 2002 and 2003, NIOSH investigators collected personal breathing zone (PBZ) and area air samples for endotoxins, hydrogen sulfide (H2S), carbon monoxide (CO), crystalline silica, and volatile organic compounds (VOCs). Endotoxin concentrations above relative limit values were measured on two workers. However, because these employees (both painters) left the worksite while wearing the monitoring equipment during part of their work shift, the exposures cannot be said to be work related. Peak PBZ H2S concentrations up to 87 parts per million (ppm) were measured while workers used pneumatic drills and jack hammers to remove deteriorating concrete from lock walls; the NIOSH recommended ceiling value is 10 ppm. Concentrations of CO, crystalline silica, and VOCs were below applicable NIOSH and OSHA occupational exposure limits. NIOSH investigators also concluded that the locks are confined spaces. NIOSH investigators identified 71 employees as having regular or intermittent exposure to the locks during winter work; 27 were interviewed or had information in their medical records that could be abstracted to identify disease trends or patterns. Most of the 27 workers reported a history of respiratory illness including bronchitis, pneumonia, or an aggravation of their asthma while working on the locks. Although several workers provided a history of seeing their health care provider for a winter illness, only two provided a history of having been hospitalized. Given the small percentage of workers who participated in this study, we cannot draw conclusions about the relationship between winter work activities and the risk of developing acute respiratory illnesses. NIOSH investigators conclude that some employees conducting winter work at the Dwight D. Eisenhower and Bertrand H. Snell Locks on the St. Lawrence Seaway are exposed to endotoxins, H2S, and VOCs. Acute respiratory illness due to H2S or VOC exposures at the levels measured during the NIOSH evaluation is unlikely. Recommendations are provided to consider the locks as confined spaces and to increase the ventilation inside the locks while winter work activities are conducted. (Click to show less)
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(2005) Vermont Housing & Conservation Board, Montpelier, Vermont. (Click to open report)
The National Institute for Occupational Safety and Health (NIOSH) received a request in 1998 from the Vermont Housing and Conservation Board (VHCB) to evaluate worker exposures to lead-contaminated dust and the dispersion of dust to surroundings associated with exterior paint removal and surface preparation. The VHCB arranged a demonstration project that included three paint removal/surface preparation methods performed by a Vermont licensed lead abatement contractor. The objective was to determ... (Click to show more) The National Institute for Occupational Safety and Health (NIOSH) received a request in 1998 from the Vermont Housing and Conservation Board (VHCB) to evaluate worker exposures to lead-contaminated dust and the dispersion of dust to surroundings associated with exterior paint removal and surface preparation. The VHCB arranged a demonstration project that included three paint removal/surface preparation methods performed by a Vermont licensed lead abatement contractor. The objective was to determine which method produced the least amount of dust exposure and dispersion. A NIOSH site visit was made in August 1998; the sampling results were provided to the VHCB in 1999. During the demonstration project workers removed exterior lead-based paint from clapboard siding of a single- family wood-frame house using three methods: dry scraping with manual sanding, wet scraping with manual sanding, and dry scraping with power sanding. NIOSH investigators conducted task-based sampling during four trials per method. Trials took place on different sections of the painted siding. Samples collected during each were for personal breathing zone (PBZ) and area airborne lead (PbA) (both NIOSH Manual of Analytical Methods [NMAM] Method 7105), lead in paint, and lead in the dispersed surface dust (PbS). PbS samples were collected using stationary dustfall collectors, each containing a clean unfolded pre-moistened hand wipe (Wash n' Dri) centered in the tray. Eight PbS samples were collected in two rows on the ground at zero, 6, 10, and 20 feet perpendicular to the siding. The mean lead concentration measured in painted surfaces was 18.7% (range for section means 4.8%- 27%). The highest PBZ PbA exposures were measured during dry scraping/power sanding with an improperly functioning (80%-blocked) HEPA vacuum dust collection system: 820 and 1600 micrograms per cubic meter (microg/m3) as task-based time-weighted averages (TWA) over 1-2 hours. PBZ PbA concentrations during dry scraping/manual sanding were lower, ranging from 29 to 160 microg/m3, and dry scraping/power sanding with a properly functioning HEPA vacuum system and wet scraping/manual sanding produced the lowest PBZ PbA results, ranging from 3.5 to 53 microg/m3, task-based TWA. The area PbA results at 10 ft from the work surfaces were low, ranging from 0.16 to 8.2 microg/m3. For all three methods, mean concentrations of PbS measured on the ground at zero ft and 6 ft from the house foundation ranged from 1300 to 7,600,000 microg/f2. After statistically controlling for distance, method, paint Pb concentration and the percent paint removed from substrate in a linear model, distance was significantly associated with PbS (p-value= < 0.0001). NIOSH investigators found that worker exposures to lead during dry scraping/power sanding without functional dust collection controls were a health hazard. Worker exposures during wet scraping/manual sanding were relatively low, but could be a health hazard if the activity is performed 8 hours or more. After paint removal, high concentrations of lead in settled dust were found at distances of zero to 10 ft from the work surfaces. Recommendations included (1) use effective engineering controls on power sanding equipment to limit lead dust exposure and dust dispersion to surroundings; (2) use respirators to reduce worker exposure to lead dust during dry scraping and power sanding until engineering and/or administrative controls are effective in reducing exposures below the OSHA PEL; and (3) use good hygiene practices. (Click to show less)
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