Evaluating Potential Health Risks in Relocatable Classrooms

Article excerpt

During periods of emergency need, California schools used 50,000 relocatable or "portable classrooms in 1996 to provide temporary school buildings.[1] This emergency use of portable classrooms ended with passage of Class Size Reduction Legislation in 1996, reducing the average class from 30 to no more than 20 students in grades K-3. This law caused a sudden and massive demand for classroom space for more than 2 million children occupying portable classrooms.[2] However, school districts were not provided sufficient guidance regarding the purchase, installation, or operation of these portable classrooms. Over time, older units showed signs of aging, including water damage from leaking roofs, providing a source for allergy and toxin-producing mold. Several school districts reported students and teachers suffered health problems that were potentially attributable to the relocatable classrooms.

In response to these concerns, the California Interagency Working Group on Indoor Air Quality produced an Advisory on Relocatable and Renovated Classrooms.[3] The document, which focused on design, construction, installation, and maintenance of portable classrooms, did not sufficiently address the possible health risks associated with exposure to chemical and biological agents potentially encountered by faculty, staff, and students and did not suggest procedures to better define such risks.

Currently, there is limited chemical and biological data that describe potential exposures associated with portable classroom use. California is presently seeking to gather exposure data to resolve the uncertain health risks of relocatable classrooms. Although sufficient literature describes the nature and potential uses of relocatable classrooms,[3,4] few articles[5] outline how to assess and reduce health risks in portable classrooms. This is the case despite the evidence that poor indoor air quality influences the prevalence of respiratory illness, allergy and asthma, and symptoms of sick building syndrome, and adversely impacts teacher and student performance. Incidence of increased respiratory effects including influenza, pneumonia, and bronchitis may be as high as 70%, with 18% more absences recorded in poor classroom environments than in classrooms with acceptable ventilation conditions.[6,7] In addition to adverse effects on teacher and student health, annual financial effects of lost work, school time, and health care costs per individual can be significant.[8,9] Further complicating the situation is the lack of consensus risk-based standards to interpret available exposure data. The guidelines that do exist focus on short-term (acute) health effects and do not address possible long-term (chronic) health effects. In addition, the existing guidelines do not specifically address the uncertain variation in children's sensitivity to chemical and microbiological agents when compared to that of adults.

Consensus-based guidelines describing approaches to health risk assessment, risk communication, and risk management are needed to safeguard the health of students and teachers. In the absence of such guidelines this commentary presents some general strategies for health risk assessment and communication that proved successful from recent experiences in a California school district.

In June 1999, relocatable classroom indoor air quality became an issue in the Beverly Hills (Calif.) Unified School District (BHUSD). This followed the 1994 Northridge, Calif., earthquake when conventional buildings at the school became structurally unsafe. Parent, faculty, and staff impatience grew steadily and peaked as the 1998-1999 school year ended with much discussion about relocatable classroom-related illnesses. An independent review and interpretation of previous indoor air quality measurements was requested. The Phylmar Group, Inc., worked with the BHUSD Environmental Safety Committee (ESC) to characterize potential health risks of the portable buildings by reviewing past monitoring data, establishing a scientific framework to assess data (setting "action levels"), prioritizing repairs needed to portable units, and conducting a statistically-appropriate air monitoring program to evaluate success of remedial or rehabilitative actions. …