Rochester/Gates, N.Y. (WHAM) - Gates Police Officer Shawn O'Mara holds a field test kit - all contained in a pouch less than three square inches.
"We open up the case and put a small amount of substance in the top," O'Mara said, before sealing the top. Inside the pouch, along with a sample of suspected heroin or fentanyl, are two glass vials of liquid.
"You break the ampules from the left to right and shake it," O'Mara said.
Green identifies heroin. A golden or brown color identifies fentanyl. The field tests are necessary for probable cause needed to seize suspected drugs from a scene.
Police say for the first time in the heroin epidemic, the drug itself is not responsible for a growing number of the overdoses they see. The more potent - and dangerous - fentanyl is being sold in Monroe County without a trace of heroin.
"It's very, very scary," said forensic scientist Jim Westley, a retired member of the Monroe County Medical Examiner's Office.
It has become an even bigger issue for police safety.
"The field tests haven't changed - just the circumstances," said Lt. Andrew Delyser of the Monroe County Sheriff's Office and Heroin Task Force. "Before, you would do it in your car or at your desk. Now, it's more in a designated testing area with gloves and a mask on."
Heroin comes from the opium poppy: A plant. Fentanyl is purely synthetic, made of chemicals. It sneaks its way into the U.S. hidden in other items.
"It's made by chemical companies and it's very cheap because it's 50 times stronger, and you only have to use a milligram," said Westley. The amount just the size of a grain of salt is harmful. The size of three grains: Deadly.
Fentanyl first began showing up in batches of heroin here in 2016. Now, it's taking over.
"We're seeing more and more just fentanyl - it being the only narcotic in the package," said Lt. Delyser.
It's also resistant to overdose reversal drugs such as Narcan. AMR ambulance crews carry six doses at a time. Sometimes, that is not enough for a single person who has overdosed.
"Fentanyl is so powerful that we're giving 3-5 doses at a time, and they're still not waking up. We take them to the hospital and they give them more, and they're still not waking," said Chief Medic Chris Gray.
The Monroe County Heroin Task Force maps overdoses every morning and shifts its response to where there are batches of particularly deadly drugs. Last month, first responders dispensed overdose reversal drugs a record 81 times.
Officers carry Narcan and Naloxone for situations they encounter - and now increasingly should they be necessary to save one of their own.
"A lot of us carry Narcan, so if there is that contact with heroin or fentanyl (on a scene) we can use it," said Officer O'Mara.