Update: On Saturday, additional tests from the Colorado Bureau of Investigation failed to detect THC in the community water supply. The Lincoln County Sheriff’s Office now believes the test kits used earlier showed false positives.

The original story is below:

The tests found something fishy in the water.

In the small town of Hugo, Colo., the water coursing through public pipes, officials say, has been tainted by THC. THC, as you may know, is the main psychoactive ingredient in marijuana.

On Thursday afternoon, authorities notified the town of about 800 people that the water should not be drunk, used to cook with or even to bathe. The Colorado Department of Public Health and Environment later downgraded the warning — it was safe to shower, brush teeth and do laundry with the tap water. Ingestion remained inadvisable as of late Thursday, though by Saturday the water advisory was canceled due to the lack of further evidence.

There have not been reports of health issues linked to Hugo’s water, according to an AP report on Friday. Nor did every Colorado local seem terribly distraught by the idea of a cool glass of THC.

“I might have to go drink some water,” Patsie Smith, the former mayor of Hugo, quipped to the Denver Post.

But investigators view the situation differently. The incident is being handled with “an abundance of caution,” as Capt. Michael Yowell of the Lincoln County Sheriff’s Office said in a news conference Thursday. The THC was first identified in a vial of tap water meant to serve as a negative result in a drug test.

***Attention Hugo Residents*** Earlier this afternoon Hugo Public Works notified Lincoln County Sheriff's Office that...

Posted by Lincoln County Sheriff's Office on Thursday, July 21, 2016

“However, when that water was tested, a positive indicator for THC was detected,” Yowell said, via KDVR. The sheriff’s office had tweeted earlier that the tests “began after complaints.” The office did not respond to a phone call  from The Washington Post late Thursday seeking clarification.

Perplexed by the discovery of THC, officials began examining Hugo’s wells. Town employees, local Fox outlet KDVR reported, discovered that one of the well houses showed signs of a forced entry. Subsequent field tests detected THC in a handful of locations, though the health department does not currently have “reliable information” on the THC concentrations.

Officials sealed the well in question. It will take 48 hours to flush all of that well’s water through the system, Yowell said. In the meantime, the county provided bottled water to residents.

Hovering over the town like a hazy cloud is the mystery of why the tests found THC — or who might have broken into the water supply.

It is legal to possess small amounts of marijuana in Colorado. But unlike Denver and other Colorado municipalities, Hugo does not allow the sale of marijuana. Nor are there any legal marijuana grow operations nearby. The Colorado Bureau of Investigation and the FBI have joined the Lincoln County Sheriff’s Office in an attempt to trace the THC taint to the source.

Some chemists, however, are skeptical that there is a psychoactive compound floating through Hugo’s water system.

“There is zero possibility that there’s anything like THC in the Hugo water,” Peter Perrone, owner of Gobi Analytical, told the Denver Post. Gobi Analytical is a Colorado-based recreational marijuana testing facility and the first state-approved lab of its kind.

“The amount of THC required would have to be financially ludicrous for anyone to do this as a practical joke,” said Dan Burgard, a chemist at the University of Puget Sound in Tacoma, Wash., by phone to The Washington Post. Burgard is currently studying THC traces in Washington wastewater. He does not believe that the Hugo contamination, if it exists, could stem from raw vegetable matter. Unless marijuana is smoked or cooked, the plants are not psychoactive.

“It’s probably a false positive from the test kit, that would be my gut,” he said.

Water systems have been tainted with drugs before, though most environmental concerns are about incidental exposure. Metabolized amphetamines and other ADHD medications may spike in the sewage systems of college campuses during finals season, as Burgard and his colleagues reported in April 2013. Scientists have also detected ecstasy in rivers after music festivals. But because those substances exist primarily on the back end of the sanitation cycle, such discoveries may be bad news for fish, though less threatening to humans drinking stuff that comes from a faucet.

To spike tap water with THC, a culprit would first have to dissolve the chemical. Perrone’s skepticism is based on a property known as solubility. Like oil, THC does not easily dissolve in water. In fact, overcoming THC’s poor solubility has posed a bit of a scientific boondoggle for pharmaceutical researchers.

As British and American scientists wrote in the Journal of Pharmacology and Experimental Therapeutics in 2006, even when THC is liquefied with a detergent, it is likely to precipitate — that is, undo all the hard work of dissolving and form clumps — “if care is not exercised.”

That said, novelty marijuana drinks exist. Manufacturers rely on a technical extraction process, however, to produce the liquid THC. Even then, the drinks are not typically super-potent. Mirth Provisions, a company in Washington state, offers a soda called Legal. It contains some 20 milligrams of THC per an 11.5-ounce bottle. That’s “enough to know that you’re high, but not so much as to overwhelm,” Adam Stites, founder of Mirth Provisions, told the Huffington Post in 2014.

It does not appear that anyone, including the thirstiest residents of Hugo, is in danger of being overwhelmed.

In a statement, Lincoln County Health Officer John Fox warned locals about symptoms of “marijuana excess,” including hallucinations, vomiting, elevated heart rate and paranoia, among other ill effects. But, he pointed out: “It would take more product than any of us could afford to contaminate a city water supply to the extent that people would suffer any effects.”