A mysterious illness struck an elementary school classroom in Kentucky on Mar. 19, forcing officials to call out a fleet of ambulances.

More than a dozen students got sick.

What's worse though, is no one knows why.

Three Rivers Hospital officials worked to reassure frightened parents the children were going to be OK.

"My child has breathing problems, I hope he'll be all right," said parent Angel Chaffins.

"They told me the kids needed oxygen, they were throwing up," explained Marsha Combs.

Rolling in on about a dozen ambulances, 24 exposed children and adults were put through a hazmat decontamination process.

Clothes stripped and bagged, bodies scrubbed with soap and water, all in an effort to remove whatever hospitalized at least 15 students from this fifth grade classroom at Blaine Elementary.

Victims stricken with rashes, nausea and breathing problems.

Two students were in critical condition until paramedics gave them oxygen.

"The outbreak was confined to one classroom, this was not a communicable illness and it was from an environmental source," said official, Renaye Sparks.

After treating all involved, school and health officials searched for a cause.

So far, they have figured what it was not.

Health officials say the sick kids got rashes, and they may never know what caused such a frightening school day.

Health officials say most, if not all, the children and adults have recovered.

School is now back in session, but that fifth grade classroom will stay off limits.