Powder found in an envelope at a mail processing center where anthrax (search) was discovered in 2001 has tested negative for ricin (search) and appears to be wood ash, officials said Tuesday night.

The gray, sandy powder was found Monday night leaking out of an envelope addressed to the Republican National Committee. The discovery came at about the time a white power that tested positive for the poison ricin was found in Senate Majority Leader Bill Frist's office in Washington.

Mark Saunders, a spokesman for the U.S. Postal Service in Washington, said the substance found in Wallingford tested negative for ricin.

John Dirzius, president of the American Postal Workers (search) local at Wallingford, said the material will still be tested for possible threats, including anthrax, but appeared to be ash.

"We're all very relieved," he said.

A spokesman for the state Department of Public Health said results from other tests -- including anthrax, plague and other substances that could be used for biological warfare -- were expected later this week.

The Wallingford center had remained open as the letter's contents were tested by the state Department of Public Health. Postal workers had said they were worried about how the situation was being handled.

Anthrax spores were found at the Wallingford center in the fall of 2001. A 94-year-old Oxford woman was one of the five people nationwide who died of anthrax during that fall's unsolved attacks, and investigators believe she got the bacteria from mail that passed through the center.

Three initial tests of the center in 2001 came up negative before a fourth, more sophisticated test found lethal levels of anthrax. The center never closed, a decision workers criticized at the time.