MOSCOW — How do you explain it when a whole town can’t seem to stop dozing off?

For years, that’s what’s been happening without explanation in Kalachi, a village in north-central Kazakhstan that’s affectionately referred to as “Sleepy Hollow” – and lately it’s only been getting progressively worse.

The problem is so bad that Kazakh authorities have begun moving families out of the village and have plans to relocate some 40 families by the end of January, according to the Moscow Times.

But a team of scientists thinks it may be closer to getting to the root of the sleeping sickness, which gives its victims everything from dizzy spells to hallucinations.

Measurements taken from the homes of people who have been stricken with the sleeping sickness have revealed very high concentrations of carbon monoxide in the air — about 10 times than what is allowable in Kazakhstan — according to remarks that Sergei Lukashenko, director of the country’s National Nuclear Center’s Radiation Safety and Ecology Institute, made to Russian news service Interfax on Tuesday.

While the findings aren’t conclusive, carbon monoxide poisoning looks a lot like the symptoms those stricken by the sleeping sickness were reporting, Lukashenko pointed out.

Scientists have wrestled previously with a variety of theories about what could be causing the Kazakhs of Kalachi to konk out.

Could it have been an illness? Scientists once suspected meningitis or encephalitis, but tests ruled out such bacterial and viral infections.

What about something in the water? That was a possibility too – but tests of the soil and water also suggested that those weren't at fault.

Patients’ blood, hair and nails also didn’t shed any light on what was happening, according to a report last year in the Siberian Times.

Experts even considered the possibility that the culprit was radiation from an abandoned, Soviet-era uranium mine in nearby Krasnogorsk, where a documentary crew from RT – Russia’s state-sponsored English-language television service broadcast internationally – found radiation levels almost 17 times higher than normal last year.

But the symptoms of radiation poisoning don’t match up with what patients are reporting.

“I am positive this is not radon,” Lukashenko told Interfax. “Carbon monoxide is definitely a factor, but I cannot tell you whether this is the main and vital factor.”

Even if the cause of the drowsiness does turn out to be carbon monoxide, the 15 specialists working in Kalachi aren't sure where the dangerously high levels of the gas are coming from — and why, whatever the source, they seem to linger.

For now, they suspect the weather, Lukashenko said, explaining that Kazakhstan’s "Sleepy Hollow" — because it is actually a hollow — experiences strange weather-related phenomena: like when sometimes weather patterns cause smoke to go down chimneys instead of up. Residents have also reported that the sleeping sickness gets more frequent when the weather is warm, Interfax reported.

The residents of Kalachi – population about 680 – report incidents of sleeping sickness about three or four times a week.