HAMPDEN, Maine — Law enforcement officials have known for years that synthetic drugs from China are often mailed to Maine and other U.S. destinations, and federal lawmakers are now taking action to stop the deadly synthetics that are killing people in droves from entering the country via the postal service.

Maine is seeing more than one drug overdose death per day, and more than half are attributed to fentanyl, a lab-made opioid that is 50 times stronger than street heroin and is often shipped to the U.S. from China or India. Drug dealers buy the fentanyl cheaply and frequently mix it in with heroin to give the drug extra potency.

“Drug dealers in countries like China are taking advantage of our postal system to ship in highly dangerous synthetic drugs that end up in our communities and take the lives of our neighbors, friends and loved ones,” U.S. Sen. Angus King, I-Maine, said in a Thursday email.

King signed on as a co-sponsor of the Synthetics Trafficking and Overdose Prevention Act on March 2 and Republican U.S. Sen. Susan Collins signed on Friday. Both U.S. Reps. Chellie Pingree, a Democrat, and Bruce Poliquin, a Republican, said they support the bipartisan companion legislation in the House and they soon will be co-sponsors.

The STOP act was introduced in the U.S. Senate three weeks ago by Sens. Rob Portman, R-Ohio; Amy Klobuchar, D-Minnesota; Marco Rubio, R-Florida; and Maggie Hassan, D-New Hampshire. The House version was initiated by Reps. Pat Tiberi, R-Ohio, and Richard E. Neal, D-Massachusetts.

The legislation is intended to stop dangerous synthetic drugs, such as fentanyl, from being shipped into the United States via the postal system.

A Florida man pleaded guilty in January in Fort Lauderdale federal court to smuggling fentanyl through the U.S. mail, including one overseas package that was repackaged and labeled to go to a woman in Maine, according to a Miami Herald story.

The bill would amend the Tariff Act of 1930 to make the Postmaster General the importer of record for non-letter class mail and would require advance electronic information about shipments to be available to U.S. Customs and Border Protection.

Specifically, the STOP act would require mail shipments from foreign countries to list who is sending the package, where it is coming from, where it is going, what’s in the shipment and who is the intended recipient.

Across the nation, 91 people die every day from an opiate overdose and the number of synthetic opioid deaths increased by 72 percent between 2014 and 2015, according to the data from the Centers for Disease Control and Prevention.

China and India have been cited as the primary source countries for illicitly produced fentanyl. Companies based in these and other foreign countries take advantage of weaknesses in international mail security standards to break U.S. customs laws and regulations by shipping drugs directly through the U.S. postal system, Tiberi posted on his website.

Shipments that arrive in the U.S. through private carriers, such as FedEx or UPS, are required to have tracking data.

The U.S. Postal Service works with several agencies to stop illegal drugs from entering the country, according to Emily Spera, a U.S. Postal Inspector and public information officer for the Boston Division. Last year, 2,169 drug investigations were initiated nationally that led to 1,571 convictions, she said.

“The U.S. Postal Inspection Service is the law enforcement, crime prevention and security arm of the Postal Service,” Spera said. “The U.S. Postal Inspection Service is committed to eradicating illegal drugs and their proceeds from the U.S. mail. We continue to aggressively pursue traffickers of all forms of illegal narcotics including fentanyl.”

But having the tracking information in advance will enable inspectors to better target potential illegal packages, King said.

“Many of our cases originate with a tip,” Spera said. “Anyone with information about illegal drugs being sent or received through the U.S. mail can call the Postal Inspection Service and leave a confidential message at 1-877-876-2455.”

The number of drug-related deaths in Maine has increased steadily since 2000, when there were 60. Maine has seen record deaths in each of the last three years, with 208 overdose deaths in 2014 and 272 in 2015. In 2016, there were 378 overdose deaths — 195 linked to fentanyl, according to data released by Attorney General Janet Mills. Only nine overdose deaths in Maine were linked to fentanyl in 2013.

Maine Drug Enforcement Agency investigators made the biggest fentanyl-laced heroin bust in Maine history at the end of January, when eight pounds, valued at $1.8 million, was removed from the streets in joint raids in southern Maine and Massachusetts.

“Drug dealers are going to use any means available,” to bring drugs to Maine, said MDEA Cmdr. Scott Pelletier, who described the January bust as “mind boggling.”

Mexican cartels are responsible for most of the fentanyl that arrives in the United States, Pelletier said, adding it arrives on the “same routes” other illegal street drugs have traditionally arrived.

What is disturbing is that local drug dealers don’t know what they are selling, which is the reason why people are dying, Pelletier said Friday. Many users who think they are taking heroin instead are taking the much stronger fentanyl-laced heroin or straight fentanyl, and they end up overdosing, he said.

“They don’t know if it’s heroin or fentanyl,” Pelletier said. “It truly is the Russian Roulette of drugs out there.”

Fentanyl is so dangerous that undercover drug agents all carry Narcan, an opioid antidote that they can use in case of accidental exposure, Pelletier said.

China, in the fall, did officially ban the production of fentanyl and a slew of other synthetic drugs, including alpha-PVP, one form of bath salts that made its way to Maine and is blamed for at least one death.

The MDEA recently assisted the U.S. Postal Service and U.S. Department of Homeland Security’s Immigration and Customs Enforcement with a case in the midcoast area that involved someone using the “dark web“ underground marketplace to order opiates, Pelletier said.

“With the ‘dark web,’ people are able to buy drugs from China and all the other places,” he said of the online marketplace. “Whatever you want, it’s there.”

The STOP act will give law enforcement officers another tool in the fight against the drug epidemic that has destroyed lives in the United States, King said.

“It’s got to stop,” he said, “and this bill aims to do that by giving U.S. drug enforcement agents the tools they need to better track illicit packages and prevent them from crossing our borders and infiltrating our communities.”