Nearly a dozen Clinton Correctional Facility employees were transported to a hospital after being exposed to an unidentified hazmat substance Friday morning. GET THE LATEST: Download the MyNBC5 appState correctional officials said an unknown substance, now believed to be fentanyl, was found inside of a letter Friday morning, causing 11 staff members to report feeling ill. Those staff members were transported to the UVM Health Network at CVPH in Plattsburgh. One sergeant had to be treated with lifesaving Narcan, according to state correctional officials. All staff members have been treated and released. Gov. Andrew Cuomo released a statement Friday, in which he identified the substance as fentanyl. "While testing is ongoing, it is believed this substance is fentanyl," Cuomo said. "Fentanyl and other synthetic opioids have sparked a public health crisis that continues to ravage our communities and takes countless lives." The envelope and substance in question have been transported to the Wadsworth Center in Albany for testing.

Nearly a dozen Clinton Correctional Facility employees were transported to a hospital after being exposed to an unidentified hazmat substance Friday morning.

GET THE LATEST: Download the MyNBC5 app


State correctional officials said an unknown substance, now believed to be fentanyl, was found inside of a letter Friday morning, causing 11 staff members to report feeling ill.

Those staff members were transported to the UVM Health Network at CVPH in Plattsburgh. One sergeant had to be treated with lifesaving Narcan, according to state correctional officials. All staff members have been treated and released.

Gov. Andrew Cuomo released a statement Friday, in which he identified the substance as fentanyl.

"While testing is ongoing, it is believed this substance is fentanyl," Cuomo said. "Fentanyl and other synthetic opioids have sparked a public health crisis that continues to ravage our communities and takes countless lives."

The envelope and substance in question have been transported to the Wadsworth Center in Albany for testing.