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Health Hazard Evaluations


Do you think a health hazard exists in your workplace? Do any of the following stories resemble situations at your workplace?

  • A factory worker was feeling numbness and tingling in her fingers. She learned that three coworkers had the same problem, and two had headaches while at work but not over the weekend. Some workers said the air at work smelled bad. Their supervisor noticed the smell but didn’t think it was anything to worry about.

  • Roofers cutting tileA manager noticed that employees in one work area had more skin rashes in the past year than the year before. He wanted to know why, but didn’t know what to do.

  • A work crew was putting cement tiles on a roof. They were working outside, but the air seemed dusty. The saws used to cut the tiles were noisy. Someone told them that this work was dangerous and they should have it checked out.

At no cost to employers or employees, or their representatives, the NIOSH Health Hazard Evaluation (HHE) program may be able to help with problems like these. This site lets you know about the program and how to ask for NIOSH help. It also has links to reports from thousands of HHEs done by NIOSH.

New Health Hazard Evaluations

  • Evaluation of potential exposure to carbon monoxide and metals. The HHE Program responded to a request at a state vehicle maintenance garage. The request concerned potential exposure to carbon monoxide (CO) and metals such as arsenic, cadmium, and lead that may have accumulated on work surfaces throughout the garage. HHE Program investigators measured CO when vehicles were running in the garage and collected surface wipe samples for metals on work and non-work surfaces.  The investigators found that CO concentrations were well below occupational exposure limits. Arsenic was not detected in any of the surface wipe samples. Low concentrations of cadmium and relatively high surface lead concentrations were detected on the bench grinder and chain saw sharpener workbenches. Leadsconcentrations were either not detected or in trace concentrations on other work and non-work surfaces. HHE Program investigators recommended that vehicles not be permitted to idle in the garage and that both garage doors be kept open and exhaust fans used when vehicles are running. Investigators recommended that managers ensure that the bench grinder and chain saw sharpener workbench surfaces are cleaned each day after use. Investigators recommended that employees remove personal protective equipment before using the break or kitchen areas and store it in a clean area when not in use.  Employees should wash hands before eating, drinking, or smoking to prevent ingestion of lead and other metals. The final report is available at

  • Evaluation of potential exposures related to mixing clays and glazes.The HHE Program responded to a request at a pottery shop which concerned potential exposures to silica, volatile organic compounds, and dry materials mixed there. HHE Program investigators collected personal breathing zone and area air samples, surface wipe samples, measured carbon monoxide (CO) during forklift use, and performed an ergonomic assessment of work practices. Investigators found that one employee’s exposure for silica was at the NIOSH recommended exposure limit of 0.05 mg/m3. They also found that some samples taken during high dust-generating tasks exceeded the excursion limit for silica. CO levels measured in the facility exceeded the NIOSH ceiling limit of 200 parts per million during forklift use. Investigators also noticed that some workers were not wearing their respirators properly.  HHE Program investigators recommended that facility managers install local exhaust ventilation in high dust-generating task areas and improve the central building ventilation to increase overall air mixing. Investigators also recommended that managers ensure that employees wear respirators and that employees use respirators when needed. HHE Program investigators also recommended that employees properly store and maintain all personal protective equipment. The final report is available at

  • Evaluation of the effectiveness of gaseous chlorine dioxide.  The HHE Program responded to a management request from an urban rehabilitation company. The request concerned evaluating the effectiveness of using gaseous chlorine dioxide (CIO2) treatments to reduce microbial contamination in a house being renovated. HHE Program investigators collected air samples, sticky tape samples from surfaces, and wipe samples before and after CIO2 treatment. Investigators found that culturable bacteria and fungi concentrations were significantly decreased after the CIO2 treatment. There were no significant differences in airborne endotoxin and betaglucan concentrations before and after CIO2 treatment. Investigators also found that microscopic analyses of tape samples collected after treatment showed that fungal structures were still present on surfaces. HHE Program investigators recommended that managers use additional clean-up techniques, such as using high efficiency particle air filter vacuums in order to reduce concentrations of spores and microbial components before re-occupancy is permitted. The final report is available at

  • Evaluation of various health hazards. The HHE Program responded to a request from union representatives concerned about heat stress, noise, and muscloskeletal hazards at an automotive parts manufacturing facility. HHE Program investigators conducted heat stress monitoring, measured noise levels, reviewed OSHA illness and injury logs, conducted medical evaluations and interviewed workers. HHE Program investigators found that there was a potential for heat stress among loaders and unloaders. Investigators also found that ergonomic hazards did exist for certain jobs.  Investigators also found that the number of workers with normal hearing levels declined between 2002 and 2003. HHE Program investigators recommended that managers make changes to reduce ergonomic stressors for certain jobs.  Recommendations were made to managers concerning heat stress for loaders and unloaders, such as positioning fans above those workstations and allowing those workers to rest completely after loading and unloading parts. Investigators recommended that employees drink plenty of fluids while working to help with hydration and continue to properly wear hearing protection. The final report is available at

  • Report on Respiratory and Dermal Conditions among Machine Shop Workers.
    Background: Exposure to metalworking fluid (MWF) is associated with asthma, bronchitis, and hypersensitivity pneumonitis (HP).  In HP outbreaks, microbial contamination of MWF typically has been detected with culture.  Multiple organisms have been implicated, including a rare mycobacterium, M. immunogenum

    Methods: Machine shop workers in a facility that produces aluminum wheels for the automotive industry reported recurrent pneumonias, asthma, and other respiratory symptoms that they related to MWF.  Investigators interviewed workers, managers, safety officials, and treating physicians; reviewed records of air and MWF monitoring; and analyzed MWF using culture, endotoxin and fungal glucan assays, and polymerase chain reaction (PCR) for mycobacterial DNA. 

    Results: Of six interviewed workers, five had work-related respiratory symptoms.  Two workers had diagnoses of occupational asthma, and one had a constellation of symptoms concerning to the worker’s pulmonologist for HP.  Monitoring records demonstrated air levels of MWF above the NIOSH recommended exposure limit (REL) and no or low detection of bacteria and fungi in MWF.  Culture of MWF showed minimal bacterial growth and no mycobacterial or fungal growth.  Endotoxin levels were very low (52-150 EU/ml), but glucan levels were detectable (133-266 ng/ml).  Nearly all (11/12) samples had mycobacterial DNA, specifically M. immunogenum.

    Conclusions: Negative MWF cultures do not preclude the occurrence of MWF-related symptoms.  Non-culture analytic methods, including glucan analysis and PCR for mycobacterial DNA, can provide useful information about microbial presence in MWF.  The final report is available at
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