WASHINGTON?Sen. Patrick Leahy says there was enough anthrax in the letter sent to his office to kill more than 100,000 people.

The letter to the Vermont Democrat was discovered Nov. 16 in a batch of unopened mail sent to Capitol Hill and quarantined since the discovery of an anthrax contaminated letter to Senate Majority Leader Tom Daschle, D S.D., on Oct. 15.

“We still haven’t got the letter open,” Leahy said Sunday on NBC’s “Meet the Press.” “It is so powerful that they’re having difficulty figuring out how best to open it and preserve the evidence.”

An FBI microbiologist said last week that there were billions of spores inside the letter, which was taped around the edges. “You could feel the powder inside,” the microbiologist told reporters.

Daschle said Americans should be careful opening the mail.

Leahy said he would leave it to the FBI to determine the anthrax’s origin.