How do you design an office building that protects inhabitants from explosions and chemical warfare without creating a structure that looks like a high-rise bomb shelter? At Weidlinger Associates, a New York City-based structural engineering company with 50 years of experience in protecting buildings, Peter DiMaggio's clientele have historically been high-risk entities such as government buildings and labs that do animal testing, but that's no longer the case. "Collateral damage has become a big issue," DiMaggio says. "In the cases of the Murrah Building in Oklahoma City and the World Trade Center, a large number of buildings in the general area sustained a lot of damage." Companies that have high-rise buildings or locations in the vicinity of possible targets want to mitigate physical risk. Here are design steps that companies can take to safeguard new facilities or retrofit current buildings. Control vehicle proximity to the building when possible. This is accomplished by placing bollards or large planters around the perimeter to create a cushion of space between the facility and an explosion. Move air intake grilles from the street to the roof to protect the air supply from chemical and biological agents. Strengthen columns and floor slabs so that the building maintains its structural integrity in the event of an explosion. If a building can remain standing for even one or two hours before it collapses, that can make a difference in the human toll. Work with architects to provide a greater degree of fireproofing. Use laminated glassthe kind found in car windshieldson the exterior of the building to protect personnel inside. All of these steps enhance a building's security without compromising cost or aesthetics. "If you start backing away from great architecture for the sake of security, then we've already lost the battle to the terrorists," DiMaggio says.