Health Hazard Evaluation Report: HETA-2008-0151-3134, July 2011. Assessment of Mold and Indoor Environmental Quality in a Middle School - Texas

摘要

In March 2008, NIOSH received an HHE request from management at a middle school in Texas concerning a history of mold contamination. NIOSH had conducted an HHE at this school in September 2007; the school was closed from September 2007 until March 2008 for repairs and mold remediation. NIOSH was asked to conduct a follow-up evaluation to look at the current IEQ conditions at the school. In April 2008, we visited the school and looked at building conditions. We met with management and employees to discuss current issues. We measured CO2, CO, temperature, and RH; used thermal imaging to look at temperature gradients; and collected sticky tape samples on furniture and ceiling surfaces to look for mold growth. At the request of the school district, the city health department conducted a parallel investigation to evaluate health concerns among the students. We found that management had addressed many of the problems identified in the 2007 NIOSH evaluation including cleaning the ventilation units and repairing the annex flashing and leaking pipes in crawl spaces. The visible mold contamination had also been cleaned. However, we did find some areas of mold contamination on wooden furniture and in the hallways. Air temperatures were below recommended ANSI/ASHRAE comfort guidelines, while RH levels were above ANSI/ASHRAE guidelines. Three classrooms had high CO2 concentrations, which indicated that not enough outdoor air was being introduced into the space. Several of the windows did not close tightly, resulting in unconditioned air entering the school. Subsequent discussions with the school administration officials revealed that the windows in the school were replaced after our site visit. When the school first reopened in March 2008, employees had headaches and nausea. These symptoms resolved after a short time and were thought to be related to the odors from the remodeling work. The employees reported that the classrooms were cold. Some employees who had pre-existing allergies moved to other schools. The city health department found no differences in the frequency or type of visit to the school nurse for the students in the time frame of our evaluations.