Concerned that the tens of thousands of escape hoods purchased by the legislative and executive branches have not been independently certified for efficacy, Rep. Ed Markey (D-Mass.) sent a letter Friday to Homeland Security Secretary Tom Ridge requesting his department answer outstanding questions about the mask’s function in a biological or chemical attack.

Congress purchased 25,000 of the devices, at a cost of about $100 each, and distributed them to offices last year.

“It is my understanding that the Quick2000 escape hoods only have been tested for a relatively small subset of chemical warfare agents such as sarin and mustard gas. It is also my understanding that they have not been proven effective against a broader array of agents or organic compounds that may be present during a [chemical, biological, radiological or nuclear] attack,” wrote Markey, a senior member of the Homeland Security Committee.

“Most startlingly, they appear not to have been tested for the most recent form of biological attack — finely milled ‘weaponized’ anthrax — which was launched against the Capitol and which fatally contaminated the Brentwood Postal Facility,” the letter continued.

But Markey retracted that latter assertion Tuesday after the company informed his office that it has tested the hoods against biological particles smaller — and thus more likely to pass through a breathing device —than the anthrax spores that contaminated Senate and House offices in October 2001.

“Since sending a letter to Homeland Security Department Secretary Tom Ridge last Friday, I have been informed by Survivair, the manufacturer of the Quick2000 escape hoods distributed to Members, congressional staff and others, that the company has tested its escape hood against biological particulates that are 0.3 microns in size and larger,” Markey said in a statement released late Tuesday afternoon, adding that weaponized anthrax spores are at least 1 micron in size.

“Therefore, it is possible to conclude that the escape hoods have been found by the manufacturer to be effective in blocking the type of anthrax used on the attack on the Capitol.”

It was never the manufacturer’s assertions, however, in which Markey claimed to be interested. In his letter to Ridge, the Massachusetts Democrat specifically referred to the lack of certification by the National Institute for Occupational Safety and Health. “According to [NIOSH’s] Web site, relevant standards for testing escape hoods such as the Quick2000 still are in draft form, and NIOSH-tested escape hoods that are certified against CBRN hazards will not be available in the marketplace until early next year,” he wrote to the Homeland Security secretary, requesting a reply by March 31.

But Markey changed his tone in his updated statement, saying that while NIOSH has not yet completed its testing, he credited them for beginning the process. He also added that the Army’s Soldier, Biological and Chemical Command has tested the Quick2000 against an array of agents.

“The ‘perfect’ should never be the enemy of the ‘good,’ and the ongoing war on terror has forced us to quickly confront dangers that were, not long ago, unimaginable,” he said in the revised statement.

“I encourage NIOSH to accelerate its CBRN testing and certification process for the escape hoods,” Markey added. “The sooner that NIOSH can corroborate what the manufacturer has found in its own laboratory testing, the more quickly everyone will be able to have an even higher level of confidence in the Quick2000.”

Capitol Police spokeswoman Jessica Gissubel said the force would like to see the agency’s evaluation of the devices.

“We’re anxiously awaiting any type of NIOSH studies to come out, but at this time something is better than nothing,” she said, which is consistent with what Police Chief Terrance Gainer has said for months about the decision to purchase the devices.

When the Quick2000 escape hoods were purchased for Members, staffers and visitors, the product was the only one of its kind on the market, she added.

The product is manufactured by Survivair of Santa Ana, Calif. According to the company’s Web site, the masks contain a high performance filter made of “military grade carbon to absorb chemical gases and HEPA grade media to remove biological particles.”

The masks are designed to provide a window of time — from minutes to an hour, depending on conditions — to escape an area contaminated with a biological or chemical agent. The devices have been distributed to Congressional offices as part of their emergency kits, and scores of training classes have been held for staff and Members.