By Courtney Sherwood
PORTLAND, Ore. (Reuters) - The FBI is investigating at least 20 letters received by law enforcement agencies across Oregon on Monday after a rural sheriff was hospitalized following exposure to an unidentified white powder in an envelope, officials in the state said.
Sheriff Glenn Palmer of Grant County was exposed to an unknown "chemical substance" after opening a letter delivered to his office, a department dispatcher said.
Palmer was hospitalized after developing a rash and was being treated early Monday evening, said Eric Schmidt, communications manager for the Association of Oregon Counties.
The association alerted the state's 36 counties to the suspicious envelopes, Schmidt said.
Oregon State Police said in a statement on Monday they had called in hazardous-materials teams to investigate the mail in question, but it was not immediately clear how many of the letters contained the powder.
Schmidt said the Federal Bureau of Investigation (FBI) was also investigating the envelopes.
"As far as we know, the letters we are aware of have gone to county sheriffs and no one else, but we might open up the mail tomorrow morning and find something of a surprise," Schmidt said.
At least one sheriff's department had reported opening an envelope and not finding powder inside, Schmidt said.
In their statement, state police warned people to be cautious of mail "that has excessive postage, no return address, excessive tape to secure parcel, misspelled words, misspelled title with name incorrect or title only, strange odors, and oily stains, discolorations, crystallization on packaging."
(Reporting by Courtney Sherwood in Portland, Oregon; Editing by Eric M. Johnson and Clarence Fernandez)