A Washington postal worker told 911 operators he was sure he had anthrax and recalled a co-worker handling a powder-containing letter a week earlier.

"My breathing is very, very labored," Thomas Morris Jr. told 911 operators the morning of Oct. 21, just hours before he died of inhaled anthrax. "I suspect that I might have been exposed to anthrax."

Postal inspectors are investigating Morris' dying words in the hopes of gaining some insight into the incident.

Morris, a Prince George's County resident, was one of two Washington postal workers who died of inhaled anthrax last month, setting off a massive investigation that has closed contaminated post offices and put thousands of workers on protective antibiotics.

The 911 tape, first aired by WRC-TV in Washington, shows emergency operators dispatched an ambulance when Morris revealed he worked at the Brentwood mail processing facility. That facility processed the anthrax-tainted letter Senate Majority Leader Thomas Daschle, D-S.D., had received the previous week.

Morris told operators he had been told that a powder-containing envelope handled by a co-worker did not contain anthrax. He said he didn't believe the assurances.

Morris' references apparently are to another letter, not Daschle's, but "we don't know for certain what he is talking about," said Deborah Willhite, a Postal Service senior vice president.

Inspectors began interviewing Morris' co-workers Wednesday to try to reconstruct the event. That is difficult because they don't have access to work records inside Brentwood, which is sealed and awaiting decontamination.

"I'm not downplaying what Mr. Morris experienced because we don't know for sure, but it could or could not be a significant lead," Willhite said, noting that post offices routinely handle damaged mail containing sugar or other innocuous substances. "We just simply won't know until we can reconstruct what went on at that point in time."

Three days before his death, Morris went to a doctor who said he likely had a virus, not anthrax, and prescribed Tylenol.

"To have that tape... lets us all know just how much different the world would be if we had known three weeks ago what we know now," said Dr. Ivan Walks, Washington's health director.

Today, no doctor in America would assume a postal worker who claimed to have had a possible anthrax exposure was suffering benign symptoms, Walks said. But at the time Morris fell ill, officials had no reason to be so suspicious.

"Anyone looking at that transcript and using what we know now to judge either his doctor or his co-workers is being unfair," Walks said.

The Associated Press contributed to this report.