Hours later, the mother woke and found her daughter struggling to breathe, according to investigators who described the scene in court documents.

After being rushed in an ambulance to a hospital, the 15-month-old girl died from a fentanyl overdose. Her mother and father, whom authorities said brought the drugs into their California home, were charged with murder and are awaiting trial.

The couple has pleaded not guilty but are part of a growing number of parents across the U.S. being charged amid an escalating opioid crisis that has claimed an increasing number of children as collateral victims.

Some 20 states have so-called “drug-induced homicide” laws, which allow prosecutors to press murder or manslaughter charges against anyone who supplies or exposes a person to drugs causing a fatal overdose. The laws are intended to target drug dealers.

In California, where the Legislature has failed to pass such laws, prosecutors in at least three counties are turning to drunk driving laws to charge parents whose children die from fentanyl overdose. It’s a unique approach that will soon be tested in court as the cases head to trial.

Supporters of the ramped-up enforcement say that by now those who use the synthetic opioid know the lethality of the drug and, like drunk drivers, they should know the consequences of exposing their children to their actions.

Critics say the parents didn’t intend to kill their children but instead made poor choices because of their addictions and are being further punished instead of being offered help.

The debate comes as the country battles with how to effectively diminish the use of the highly accessible and extremely deadly drug.

Authorities believe some of the children died after touching something with the powdery substance and then touching their eyes or mouth. In one case, the drug may have been on the hands of a parent who prepared the baby’s bottle. The drug is not absorbed into the skin but experts say it can be lethal if as little as 2 milligrams, about the weight of a mosquito, enters the body.

“These are tragic cases because drug addiction has destroyed a precious life and the parents face the consequences of their reckless actions,” said Charlie Smith, the top prosecutor in Frederick County, Maryland, and president of the National District Attorneys Association.

Parents also can face charges if young children become seriously ill or die from crack, heroin and cocaine, but such cases are rare because a sizeable amount must be ingested, Smith said.

“This is really a first in the history of our country because we have a drug on the streets that can potentially kill you instantly with a minor amount of product,” Smith said.

Prosecutors have a difficult decision to make when determining whether to charge parents, but Smith said the goal is to deter others from doing the same.

He prosecuted a case in which parents in Maryland were convicted of involuntary manslaughter in the 2020 death of their 2-month-old son. The Mount Airy couple had mixed fentanyl in the same bathroom where they prepared bottles for their infant.

Jeremy Whitney Frazier and Heather Marie Frazier were each sentenced in December to five years in prison and five years of supervised probation.

The National District Attorneys Association doesn’t track how many parents have been charged for exposing their children to fentanyl, but news reports and interviews with prosecutors show such cases have been on the rise since the onset of the pandemic.

Last month, a Maine woman pleaded guilty to manslaughter after her 14-month-old son’s fentanyl overdose. Investigators found fentanyl on a blanket and sheet where Ashley Malloy’s son Karson had been sleeping.

States such as Maryland that don’t have “drug-induced homicide” laws often charge parents with manslaughter, Smith said.

In California, prosecutors have turned to a drunk driving law.

Prosecutors in Riverside, Sonoma and Stanislaus counties have charged parents with murder based on the “Watson advisement,” a formal statement signed by anyone convicted of a DUI charge who says they understand driving under the influence can injure or kill people. The statement can be used against them if they cause another fatal, DUI-related crash.

“I’ve been a prosecutor 25 years now and I can’t recall any other drug that has led to this much destruction and death,” Riverside County Deputy District Attorney Daima Calhoun said.

Prosecutors say the parents, like drunk drivers, knew fentanyl can injure or kill people.

Among those awaiting a trial that will test the approach are Tehra Alexandra Waite and Collin Pascal Kittrell, both of Riverside. The boyfriend and girlfriend were charged with murder after their toddler died of a fentanyl overdose in June 2020. They pleaded not guilty.

Investigators said their 14-month-old daughter, Allison, likely touched her mouth or eyes after coming in contact with the drug, which was found on several things in their apartment, including the couch.

Detectives testified that when Waite found her daughter unresponsive she rushed to a pharmacy to buy naloxone, a drug used to reverse an opioid overdose. The couple did not call 911 until hours later when Allison started having trouble breathing.

The girl’s paternal grandmother also said in court documents that Waite used drugs while she was pregnant.

The Associated Press sought comment from multiple attorneys who have represented Waite and none responded. Her father declined to comment.

Kittrell’s attorney, Graham Donath, said Allison’s father did not intend for his child to die and the charge should be one of child neglect, not murder. But prosecutors don’t like to go that route because the maximum sentence for the offense is 12 years.

In Sonoma County, where Charlotte slept with her mom in a messy apartment in Santa Rosa, first responders testified at a preliminary hearing that they found fentanyl in powder form on a nightstand next to the bed.

Ryan Hughes, a Santa Rosa Police Department narcotics detective, told the court they also found text messages showing the couple was concerned about losing their daughter because of their drug use, the Santa Rosa Press Democrat reported.

A judge is expected to set a trial date at a Sept. 11 hearing for Charlotte’s mother, Bernard, who woke up to find her daughter struggling to breathe, and her father, Evan Frostick.

Defense attorneys for Bernard and Frostick and Frostick’s parents all declined to comment when contacted by the AP. Bernard’s stepmother did not respond to phone messages seeking comment.

“They need to be held accountable under the law because they allowed harm to come to their children and they let their drug use and addiction outweigh taking care of their children and keeping their children safe,” Sonoma County District Attorney Carla Rodriguez said.