NIOSH staff recently conducted a health hazard evaluation of a medical center research facility in response to laboratory employees’ concerns about indoor environmental quality (IEQ) and transient odors. The workers were concerned that the odors could be causing nausea, headaches, sinus problems, and aggravation of asthma. During the evaluation, NIOSH investigators found that the supply airflow and exhaust airflow in some laboratories did not operate as designed, and supply air intakes on the roof were pulling building exhaust back into the facility. While evaluating the building’s HVAC system, agency staff also found that pressure differentials in between certain hallways, laboratories, and offices were not as designed, which NIOSH’s report states could lead to the “unplanned migration of air contaminants and odors from one area to another.”
Air samples collected throughout the building identified trace amounts of solvents, aliphatic hydrocarbons, aldehydes, aromatic hydrocarbons, chlorinated solvents, and terpenes, many of which are contaminants common in indoor environments. According to NIOSH, a wide range of materials such as paint, adhesives, and flooring materials can be a source for these compounds. Agency staff also found very low concentrations—less than 1 ppb—of the halogenated ether anesthetics sevoflurane and isoflurane, the facility’s primary anesthetic for research animals, in samples taken at the penthouse exhaust area. NIOSH’s evaluation did not cover the effectiveness of the building’s anesthetic gas evacuation systems.
NIOSH’s report recommends that the employer consult with an HVAC engineer to evaluate the design, height, and location of roof exhaust stacks to identify necessary changes to reduce re-entry of exhaust air into the building through the facility’s HVAC supply air intakes. The agency also urges the employer to consult with an experienced ventilation engineer to address ventilation deficiencies within the laboratories. In addition to testing and balancing the building’s HVAC system, NIOSH states that the employer should also stop using treated steam for building heat and humidification. NIOSH and EPA both recommend against using treated steam for this purpose because it can contain potentially harmful corrosion inhibitors.
For further details of NIOSH’s evaluation, see the full report (PDF).