Public health and law enforcement officials are warning about a powerful opioid that has been found mixed in batches of heroin in Ohio and could be headed to Western Pennsylvania.

Carfentanil, which is used to sedate elephants and other large animals, is 10,000 times stronger than morphine and is the strongest commercial opioid in the world.

On Wednesday Luzerne County District Attorney Stefanie Salavantis issued an alert on the drug, saying it is responsible for about 200 overdoses — 20 of them fatal — in Ohio near Western Pennsylvania.

Over two days in July, 91 people in Akron, Ohio, overdosed and eight died from the drug, according to news reports. Another new designer opioid, W-18, is reportedly responsible for a wave of overdoses in Eastern Pennsylvania.

News of the drugs comes about a month after the Drug Enforcement Administration’s Philadelphia Division released a report saying that the rate of fatal drug overdoses in Pennsylvania jumped from 21 per 100,000 people in 2014 to 26 per 100,000 people last year. At least one opioid was present in 81 percent of those deaths, according to the report.

Neither of the substances is believed to be responsible for any overdoses or overdose deaths in the Butler County region, public health officials said.

Tim Fennell, a detective with the County District Attorney’s Office, confirmed that law enforcement agencies in the county haven’t encountered the drugs yet, but said the office is telling officers and emergency responders to exercise caution when handling confiscated drugs and drug paraphernalia.

The major concerns surrounding carfentanil specifically are its potency and the danger it can pose to first-responders who could come into contact with it on the scene of an overdose.

In liquid form the substance is colorless and odorless, and can be absorbed through the skin. Veterinarians who handle the drug wear protective gloves, aprons and masks, and DEA officials say a dose the size of a grain of salt could kill a person.

Butler County Coroner William Young III said that once the substance makes its way into a region’s drug trade, there seems to be little way to control or predict how and when it will emerge.

“It seems like it’s so uncontrollable. I just don’t understand why the kids or adults even want to take a chance like that,” Young said. “You don’t know what you’re buying. There’s nothing that tells you what’s in that package. That’s the scary part.”

Fennell said the drugs’ emergence comes at a time when overdoses in the county are “a little behind” the pace set last year.

There were 47 drug-related deaths in Butler County in 2015, according to information released in February by the county coroner’s office. Thirty were attributed to heroin and 9 to fentanyl.

Fennell said law enforcement officials hope the powerful and deadly drugs don’t make their way into the region, but it’s hard to say when, or if, they might appear here.

“If it’s something that a certain distributor or drug dealer is adding to their heroin, hopefully it’s specific to the Ohio area, but we don’t know,” he said.

That’s a quandary for emergency responders, who in recent years have focused on life-saving treatments using the drug Narcan when responding to suspected opioid overdoses. Carfentanil is so powerful that it may take several doses of Narcan to revive a patient.

Mercer County Sheriff Gary Hartman said his county has avoided more overdose deaths because of the training given to police, EMS and fire personnel.

Hartman said the “first and foremost” overdose concern for his office continues to be fentanyl, which is often added to batches of heroin to make it more powerful. But he added that the powerful new opioids are substances he is sure will appear in the area sooner or later.

“It definitely is (coming). It’s close enough for discomfort, so to speak,” he said. “And the sad part is, we don’t believe we’ve seen the top end. We’re still in an upward spike. The DEA and FBI anticipate that it’s going to be another two years before we hit a peak.”

But it’s difficult for health officials to accurately track the number of overdoses that occur each month. Many times overdose patients either refuse to be taken to the hospital or sign themselves out once they get there, which can hinder efforts to track the incidents.

Hartman estimated that during the past three months Mercer County has had the average number of overdoses each month go from 10 or 12 to 25. And it’s not getting better, he said.

“It looks like August is probably going to double that number,” he said.

Butler County District Attorney Richard Goldinger was not available to comment for this report.

Mercer County Coroner John Libonati did not return messages left seeking comment.