A public bathroom bathed in blue light is seen at this Turkey Hill convenience store in Wilkes-Barre, Pa. (Michael Rubinkam/AP)

Isolated, easily accessible and free from surveillance cameras and security guards, public restrooms have long been a place for illicit activities. And with a relentless opioid epidemic ravaging the nation, they have become a laboratory of sorts for drug users searching for a private space to get high.

It presents a problem for business owners concerned not only about the safety of their customers but also of their employees — the ones cleaning up blood splatter, picking up used needles or calling 911 when a user has overdosed in the washroom. It has forced retailers to search for solutions such as placing cameras outside the facilities, securing the doors with lock pads or removing drop ceilings, where users often hide drug paraphernalia.

Some U.S. retailers have even tried installing blue lights in restrooms. The logic: The light makes it harder for drug users to see their veins.

Turkey Hill Minit Markets, a convenience store chain based in Lancaster, Pa., has installed blue lighting in bathrooms at 20 of its more than 260 locations to determine whether the eerie hue will deter users from using their bathrooms to inject illegal drugs, said Matt Dorgan, division asset protection manager for Turkey Hill. Since the chain installed the lighting about six months ago, Dorgan said that there has been a “dramatic reduction” in drug activity.

“With the problem across the nation with drug use, we were looking for something to get that activity off our properties,” Dorgan told The Washington Post.

Read Hayes, director of the Loss Prevention Research Council, a retail industry research group that's studying Turkey Hill's use of blue lights as a security measure, said retailers are concerned about biological hazards in their bathrooms as well as other crimes that coincide with drug use. “What we'd like to do is find out how to minimize on-site drug use,” he said.

Last year, another convenience store chain, Sheetz, put the lighting fixtures in the bathroom in a store in New Kensington, Pa., and later expanded the experiment to a store in Huntington, W.Va.

Sheetz spokesman Nick Ruffner said though the company has not quantified the lights' effectiveness as a deterrent, “we've seen steps in the right direction.”

Although clever, the security measure may present its own share of problems.

Jonathan Goyer, a former heroin addict from Providence, R.I., said when he was using, he had no home, no car and no privacy from other people or law enforcement. When he needed to get high, he said, he would hide behind bushes or, ideally, dip into a public restroom, which had the advantage of running water. He said he never encountered blue lights but said it wouldn't have deterred him.

“If addiction was able to take away my job, my family and my house — and losing that was not enough of a deterrent — a blue light would not have done the trick,” said Goyer, now an adviser on the Rhode Island governor's overdose prevention task force. Goyer said that conceptually, it's beneficial because “it creates conversations” and “brings ideas to business owners,” but he doesn't think it will work.

Goyer pointed out that nearly everyone has a flashlight on his or her cellphone and, those who don't will still try — but in dimly lit and more dangerous conditions.

A 2013 study on the subject showed that current and former drug users said that not only would the lights fail to stop them but also would create additional issues.

Most of the 18 people interviewed said they had tried to inject drugs in blue-lit bathrooms, and half of them said they would try it again “and risk the consequences, which include vein damage and infections,” lead author Alexis Crabtree said in an email. Crabtree, a public health resident physician at the University of British Columbia, noted some users said they might search for another spot “but they'd often be ending up in worse places, including public spaces.”

In fact, Dan Bigg, director of the harm-reduction organization Chicago Recovery Alliance, said that removing adequate lighting only serves to make for messier injections.

“All it does is increase the complexity of the injection, leading to a bloodier injection and a more damaging injection,” he said, noting the possibility of blood droplets on the toilet paper and the floor as users get frustrated. He added that “the more nasty an injection,” the more likely the spread of infection for both the user and others who come in contact with the injection site.

He said the solution would be good lighting, outward-swinging stall doors (so people can reach those who have overdosed) and places to dispose hazardous waste.

But security consultants say that most business owners don't want to encourage illicit drug use on their properties — they want to deter it. And that, they say, puts businesses in a difficult position, trying to strike a balance between making restrooms available and inviting for their customers without opening them up to people who might make them unclean or unsafe for others.

Blue lights in public restrooms, according to the consultants, is just one tool that businesses are beginning to try as a security measure in the United States, and “the jury's still out” on whether it will be successful.

Jon D. Groussman, president of CAP Index Inc., a security consulting firm based in Exton, Pa., said that “in certain markets where you know you’re having a problem, it's worth trying.” But he added that closely monitoring public restrooms and sending employees to check on them periodically is typically “the best deterrent.”

Dorgan, with Turkey Hill Minit Markets, said that the convenience store chain is still evaluating the experiment to determine how it's working and whether to expand it.

Read more:

Students sue University of Notre Dame for restricting access to some birth control

The blemishes moving around on her face turned out to be a parasitic worm