ASHRAE warns: some antiterrorism measures in buildings could pose health risks.

As building owners and operators look for ways to safeguard occupants, some are closing air intakes to prevent the introduction of hazardous materials into ventilation systems. But according to professionals skilled in indoor environmental control, these well-intentioned actions could create extensive health problems.

"America's buildings are amongst the safest in the world, constructed under a system of codes and standards to ensure the utmost protection of safety, comfort, and health," said William J. Coad, P.E., president of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). "Any steps taken that result in a reduction of outdoor air ventilation rates or a change in the manner of providing and treating the ventilation air could seriously change the engineered balance of the interior environment. "Such changes can result in many of the manifestations of sick-building syndrome, including maladies such as discomfort; eye, nose, and throat irritation; headaches; fatigue; lethargy; loss of productivity; upper-respiratory symptoms; and skin irritation.

Americans spend 90 percent of their time indoors. Any deterioration of the indoor environment would create major health problems.

ASHRAE and many other engineering organizations, including the U.S. Army Corps of Engineers, are re-evaluating the safety aspects of buildings in light of the terrorist attacks of September 11, 2001. Their findings will provide guidance to building operators and designers for the design and operation of buildings that will make them safer while not compromising environmental integrity. Included in their studies will be the prevention of hazardous material entry into ventilation systems.