It has been more than a year since letters laced with anthrax terrorized the nation, and subsequent false alarms of harmless white powders helped to maintain the tension.

During that time, Mercer County remained relatively unscathed from the scare, at least until recently.

Sheriff Bill Romine said Monday his department is investigating a June 27 incident in which a county jail guard became sick after opening a letter addressed to an inmate that contained an unknown substance.

Warden Jeffrey Gill said he believed it was the first time such an incident occurred at the jail.

The substance, described by Gill as an "off-white powder," caused the female guard, who was not identified, to become ill "within minutes" and she had to be taken to the emergency room of a local hospital where she "received treatment and then returned to work."

"I can't positively tell you that there is an absolute that one caused the other," Gill cautioned. "I don't know at this point. That's what is still under investigation. We're still waiting for the mail to come back from the crime lab."

Gill emphasized that anthrax and like substances have been ruled out.

Romine confirmed that information would be made available when the investigation is complete.

"Right now there is an indication that it wasn't anything that was a real danger to everybody, but it possibly was a substance that could cause some illness if absorbed by the skin," Romine said. "At this time, we're not sure what it is. It's being investigated and once we find out there will possibly be charges filed."

Charges against the sender, he added, could include all or any of the following: assault or drug or contraband possession.

As for whether the inmate to whom the letter was addressed would also be charged, Romine said, "We have to look at how it was brought in, who placed it there and the circumstances."

Gill said the jail has instituted some protocols, including guards wearing gloves when they open mail, in an effort to avoid similar situations.

You can e-mail Herald Political Writer Jeff Greenburg at jgreenburg@sharonherald.com.