Sens. Angus King of Maine and Joe Manchin of West Virginia proposed a bill Tuesday that would impose a fee on prescription opioids as a way to pay for substance abuse treatment, housing, employment services and other programs that would alleviate the country’s opioid epidemic.

In Maine, 272 people died from drug overdoses in 2015, with most of the deaths caused by heroin, prescription opioids or fentanyl. About 25,000 to 30,000 Mainers want drug treatment but do not have access to therapy, according to the U.S. Substance Abuse and Mental Health Services Administration.

Nationwide, the number of people dying from drug overdoses now surpasses deaths from motor vehicle accidents, with 47,055 overdose deaths in 2014 compared to 32,675 fatal vehicle accidents in the same year, according to federal data.

The fee would be one cent on each milligram of active opioid ingredients in prescription painkillers, and would generate an estimated $1.5 billion to $2 billion per year. Many patients would not directly pay the fee because of how their insurance coverage pays for prescriptions.

King, in a phone interview Tuesday with the Press Herald, said treatment programs must be funded, and tacking it on to the price of the drug is a fair way to do it.

“The obvious way to fund this is to build it into the price of the drug,” said King, comparing it to how the cost of seat belts and air bags are factored into the price of a vehicle. “The cost of the drug should reflect the danger of the drug.”

King said the fee would vary depending on dose and type of drug, but would roughly range between 75 cents to $3 per 30-day prescription.

King hasn’t heard yet whether drug companies will support the fees, but he said they bear responsibility for flooding the market with prescription opioids, starting in the late 1990s and 2000s. The drug companies touted the safety of opioids, when in fact the painkillers are dangerous and helped fuel the expansion of heroin addiction, he said.

Four out of five heroin addicts were first addicted to prescription opioids, according to the American Society of Addiction Medicine.

Dr. Mary Dowd, a physician who treats addicts at the Milestone Foundation and Catholic Charities in Portland, said more treatment and other supports to help people beat addictions – such as jobs and stable housing – would go a long way to helping.

“It would be a wonderful thing if it happens,” Dowd said.

Democratic Sens. Jeanne Shaheen of New Hampshire, Heidi Heitkamp of North Dakota, Amy Klobuchar of Minnesota, Tammy Baldwin of Wisconsin and Bill Nelson of Florida have signed on as co-sponsors, in addition to King, an independent, and Manchin, a Democrat.

The bill does not yet have any Republican co-sponsors, and it’s unclear whether it would attract bipartisan support.

Maine’s senior senator, Republican Susan Collins, has not yet taken a position on the bill.

“This legislation was introduced (Tuesday). We have not yet had a chance to review it, but look forward to doing so,” said Annie Clark, Collins’ spokeswoman.

King plans to lobby for the bill and hopes it will gain bipartisan support. He hasn’t spoken yet with Collins, but he intends to discuss the concept with her. A bill to expand treatment for opioids was recently approved by Congress with Democratic and Republican support, but there was no funding attached to it.

King’s bill would carve out exceptions to the fee for opioids used to treat cancer pain, hospice care and for prescriptions used to treat addiction, such as Suboxone.

The proposal also would expand access to treatment by increasing reimbursement for mental health care providers who do substance abuse therapy. Public health experts have said that one barrier to treatment is that doctors are often unwilling to take on patients who are addicted to opioids.

It also would provide funding for neonatal services to help drug-affected babies, and housing and jobs programs to help addicts.

King said access to treatment is a key to reducing the opioid epidemic.

“The biggest tragedy is when people say they need help and they’re ready to beat their addictions, and we tell them they have to wait three months to get into a program,” King said.