Though their offices were destroyed on Sept. 11, the 21 employees of the Occupational Safety and Health Administration's Manhattan office have had little time to absorb that loss. Instead, many Manhattan-based OSHA employees have helped the agency provide 24-hour service at ground zero--the site where the World Trade Center's twin towers and several other buildings stood before two hijacked planes crashed into the towers on Sept. 11. "My staff was there before hour one," said Richard Mendelson, director of OSHA's Manhattan area office. "We're doubly affected. We can't just walk away and forget about things from Sept. 11. It's hard to watch your building be demolished knowing that you used to work there and 3,000 people died there." OSHA's Manhattan-area employees evacuated their building in the World Trade Center Complex with little mishap following the terrorist attacks. The agency had a well-developed evacuation plan based on lessons learned after the 1993 World Trade Center bombing. Even the contingency plan had a contingency plan, Mendelson said. When employees found their designated meeting spot inaccessible due to smoke and flying debris, they walked to the agency's nearby regional offices and began coordinating their response. When the towers collapsed, the agency's regional offices were evacuated as well, so the group found yet another spot to meet and continued to craft a plan of action to carry out the agency's mission: to help prevent workers from being injured. In the nearly five months since the attacks, OSHA employees have worked around the clock, providing advice and technical assistance to employers and federal agencies to help protect workers from exposure to hazardous substances. OSHA workers distributed at least 4,000 respirators a day during the first days after the attacks. They then worked with the Environmental Protection Agency to test air, water and dust for pollutants that could create health hazards within a several block radius of ground zero-pollutants such as asbestos, radiation, mercury, other metals, pesticides and bacteria. They also advised Consolidated Edison, the utilities company that serves New York City, about safety standards for employees digging trenches to fix leaking underground gas lines. "We were able to put people out in the field very, very early after the collapse to advise the contractors and other employers out there rebuilding about potential hazards," Mendelson said. OSHA's Manhattan-based employees are still trying to find new office space. Right now they are crammed into a 22-foot by 22-foot room. "The computers are touching each other. It's like a bullpen, really," Mendelson said. In the meantime, OSHA officials have tried to stay in tune with their employees' needs, working closely with the agency's employee assistance program and finding ways to accommodate employees who do not want to return to ground zero. "The overwhelming desire is that people want to go back down there, but we wanted everyone to know that there is no shame involved in being emotionally distraught," Mendelson said.