MEXICO CITY (AP) — A one-year-old child died and a four-year-old has recovered after being exposed to the deadly synthetic opioid fentanyl in the drug-plagued northern Mexico state of Sinaloa, authorities said Monday.

The state’s governor acknowledged that so far this year, a total of four children have been treated for exposure to fentanyl in Sinaloa, Mexico’s best-known drug-trafficking state and home to the cartel of the same name.

But Gov. Ruben Rocha sought to downplay the issue at a news conference Monday, saying that so far “only one child has died, the other three didn’t.” He also at one point claimed there was no fentanyl in his state, despite its reputation for being a major producer.

Rocha said the kids may have been exposed through contact with an addict or someone who worked in a clandestine fentanyl pill-pressing workshop, which are common in the state and which press fentanyl powder into fake pills made to look like Oxycontin, Valium, Xanax or other medications.

Many people in the United States have died because they took pills they didn’t know contained fentanyl. Fentanyl addiction is still rare in Mexico, because the pills go for export.

Rocha claimed that fentanyl “is not allowed in” to Sinaloa state. “There is no fentanyl, what is known as the active substance,” he told the news conference, echoing claims made by President Andrés Manuel López Obrador.

However, experts agree that Mexican cartels import precursor chemicals from China, process them into fentanyl and then ship pills to the United States.

Rocha said there were no drug “laboratories” in his state, though he conceded there were drug “workshops.” And when he described one of these suspected workshops, he appeared to marvel at the sophistication of the traffickers in how they mix various ingredients together.

“This is to give the pill color, that is to avoid stomach aches for those who use it, this is to avoid giving users headaches — all this the traffickers are careful about,” Rocha said.

Rocha belongs to the president’s Morena party. López Obrador has sought to shed Sinaloa’s reputation for drug-trafficking, saying the state is home to “hard-working people.”

But while the state is an agricultural powerhouse, experts agree its largest single source of income is the drug trade and associated illicit businesses.

Sinaloa state Health Secretary Cuitláhuac González said the children appear to have been exposed to fentanyl at two different events last week, and that the four-year-old is expected to be released from the hospital soon.

González also ruled out the possibility that the children could have eaten drug-laced candy, a common folk belief in Mexico.

Around 70,000 adult die annually in the United States from fentanyl overdoses. But exposure to even the tiniest trace amounts of fentanyl can be deadly for small children.

In September, a child died at a New York City child care center after being exposed to fentanyl.

The 1-year-old boy, Nicholas Dominici, suddenly died at the Bronx day care center. During nap time, other children at the center experienced symptoms of opioid poisoning and needed to be revived with the drug Narcan.

In that case, police found a brick of fentanyl stored on top of playmats for the children, along with equipment often used to package drugs. A further search led to the discovery of a trap door in a play area, under which police found more packages of drugs and other materials.

Several people have been arrested in the case.