About 65 employees and patients have been quarantined and 11 were taken to the hospital after an envelope containing an unknown powder was discovered at a Wisconsin health facility Wednesday morning.
The Wisconsin State Journal reports three people complained of burning eyes after coming in contact with the package delivered to Beloit Area Community Health Center.
A thin man in his 50s with white hair and a white beard hand-delivered the envelope, the Milwaukee Journal Sentinel reports.
Authorities are working to identify the man and the substance.
City officials say they don't believe the incident is related to similar events happening nationally, including a letter addressed to President Barack Obama that tested positive for the poison ricin Wednesday.
Federal law enforcement officials say a similar letter was addressed to U.S. Sen. Roger Wicker, R-Miss.