While Congress and the Trump administration were promoting greater use of the addiction medication buprenorphine to quell the opioid epidemic, a handful of states were licensing new methadone clinics in dozens of the hardest-hit communities.

In fact, the methadone treatment industry, which began in the late 1960s, grew more in the past four years than it has in the past two decades, said Mark Parrino, president of the American Association for the Treatment of Opioid Dependence Inc., which represents methadone treatment providers.

Between 2014 and 2018, the methadone industry added 254 clinics, said data from the Drug Enforcement Administration. In the two decades before that, increases in the number of programs were only incremental, Parrino said. "We haven't seen such a dramatic increase in the industry since the 1970s."

But despite a national drumbeat for more science-based treatment for people addicted to prescription painkillers, heroin and other illicit opioids, the opioid treatment industry's expansion has mostly gone unheralded.

Unlike buprenorphine, which can be prescribed by specially licensed practitioners and taken at home, or injectable Vivitrol, which can be administered by any doctor, methadone must be doled out daily at highly regulated and often very visible clinics.

Crowded parking lots, long lines and the potential for diversion of the medication have led many states to limit the number of clinics they license.

Some politicians and many in the general public have likened methadone treatment to trading one addiction for another.

That's starting to change.

"There has been an underlying stigma against methadone for so many years that the industry naturally maintains a low profile," said Dr. Yngvild Olsen, an addiction doctor in Baltimore and board member of the American Society of Addiction Medicine.

"Even now, access to methadone is highly geographic," she said. "It depends on where you live."

In an opioid epidemic that is killing more than 130 Americans every day, more states, including some that previously limited expansion of methadone treatment, are calling on the industry to set up new programs in opioid-plagued rural and suburban areas that lack adequate medication-assisted treatment options.

And opioid treatment companies are responding, with most new clinics offering all three FDA-approved opioid addiction medications. Among the most aggressive states in seeking methadone treatment expansion have been Indiana, Maryland and New York, which have strategically sited dozens of new facilities in rural and suburban communities in the past two years. Ohio and Florida are planning major expansions this year and next.