KENT COUNTY, MI -- West Michigan police, firefighters and other rescuers are being warned to take precautions on heroin overdose calls because of the possibility of elephant tranquilizer in heroin.

Lab testing is still ongoing, but Kent County sheriff's investigators say there's some indication that the drug carfentanil was involved in a recent Kent County overdose death.

Carfentanil is typically used as a tranquilizer for large animals, including elephants, and is described as "10,000 times more potent than morphine and 100 times stronger than fentanyl."

Firefighters with several Grand Rapids area fire departments received an advisory Thursday, Sept. 15 about the drug the dangers of incidental contact.

Carfentanil can be absorbed into the skin through touch or through inhalation.

Police say typical symptoms are disorientation, coughing, sedation,

respiratory distress or cardiac arrest. The symptoms usually show up within minutes o exposure and "incidental contact with this substance can also be lethal."

Grand Rapids Township Fire Chief Robert Versluys said his firefighters are already instructed to wear medical gloves at medical calls but now they also will be wearing surgical-type masks.

Kent County Health Department spokesman Steve Kelso said officials with the Kent County Health Department, state police and Michigan Department of Health and Human Services talked about the latest heroin issue on a conference call Friday, Sept. 16.

He said the purposes was simply to share the latest information available on the dangers.

"We are concerned that first-responders or even the general public could be at risk through contact," he said.