ST. CHARLES, Mo. – Officers in St. Charles are taking new steps to protect their K-9 officers from drug overdoses.

Officers with the K-9 unit will now carry Narcan.

Narcan is a medicine used to help revive people who have overdosed on deadly opioids like heroin.

Nitro is one of three K-9 officers at the St. Charles Police Department. His job is to sniff out drugs.

5 On Your Side put his skills to the test.

We put a bag of heroin in our news bag and it took Nitro only a few seconds to find it.

That's how sensitive these animals' noses are. Even the smallest amount of an opioid like heroin—could be deadly.

Lt. Tom Wilkison with the St. Charles Police Department said, “It does not take much to be inhaled or absorbed so the K-9 officers are constantly monitoring their K-9 partners.”

Officer Daniel Allen handles the K-9 officers for St. Charles.

“We look for shallow breathing. If he’s lethargic. As you can see Nitro is a very active dog. So, if I see him being lethargic, there’s some type of distress there,” he said.

St. Charles officers have been carrying Narcan for the past year. They said it has helped save dozens of people who have overdosed.

The downside is that it’s expensive. It can cost about $80 for one dose of the spray.

But when it’s used, it’s life-saving, they said.