Even those who kept them on were not necessarily protected. Many of the masks that were rushed to the site after the Sept. 11, 2001, terrorist attacks were the wrong type, or had the wrong filters. Many workers were not properly trained to use them. As a result, thousands were exposed to highly contaminated air that is suspected of making them sick, and the federal government set up a $4.3 billion health care and compensation fund for responders. Now the government and the hazardous-equipment industry are trying to do better. They are working on a new generation of respirator masks, not just for rescue and cleanup workers but to prepare for outbreaks of disease and for still another emerging threat: the accidental releases of nanoparticles, the microscopic, engineered fibers that are starting to be used in electronics, food, medicine and more. “There were a lot of lessons learned in New York,” said Maryann D’Alessandro, the director of the National Personal Protective Technology Laboratory, a federal agency responsible for research on respiratory protection and the certification of equipment. Since the attacks, the New York City Fire Department has invested more than $100 million in new respirators and other protective gear, replacing its inventory of self-contained breathing apparatus. The equipment is tested for proper fit, and firefighters and emergency medical workers are all trained to use it. The department has worked closely with the national laboratory to help develop the new certification standards. “As the largest fire service in the United States, we should be out there trying to provide as much information about these things as we can,” said Robert J. Ingram, the department’s chief for terrorism and disaster preparedness. But questions remain about whether enough has been done, especially when it comes to those who are not properly trained or equipped to respond to a major disaster, like the construction workers who helped clear debris from ground zero. “There have been clear advances in design and certification” of equipment used in response to attacks, said David M. Newman, an industrial hygienist with the New York Committee for Occupational Safety and Health. But he added, “In terms of the respirators most commonly used on a day-to-day basis and most commonly used in disaster response, I don’t see any significant changes on the ground yet.” Sometimes the issue is cost. For example, electronic sensors can tell when a respirator cartridge should be changed, but they are not yet required because they would add about $15 to the price of a reusable respirator. The national laboratory has also been accused of taking too long to develop new standards and lacking scientific evidence to justify the changes. The Right Fit The first respirators came into use in the early 20th century to protect coal miners and soldiers. Today, five million Americans work in such contaminated environments that they rely on respirators to protect them from the air they breathe. And making respirators and certifying them has become a major industry, with annual revenues around $1 billion. The government has certified more than 9,000 respirators manufactured by 93 companies in the United States and abroad. In the past year, 933 new approvals were issued. The simplest certified respirators are the familiar, lightweight N95 disposable masks, which cost a few dollars apiece and fit loosely over the nose and mouth. They are made of layers of polypropylene plastic, electrostatically charged to attract and hold contaminants like dust but not gases or oils. More sophisticated reusable respirators, with replaceable filters can cost up to $50 and are effective against an array of contaminants, from gases to asbestos, depending on their design. Scott packs and other self-contained breathing units offer the greatest protection but can be used only as long as the air in their tanks holds out, generally less than an hour. The way a respirator fits is as important as the filter itself. Since the 1970s, the government has tested new respirator masks on small groups of people whose face shape and size, particularly that of the nose and chin, are consistent with a sample of Air Force cadets who were measured in the ’60s.
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