WAUSAU, Wis. (AP) -- Nearly everyone affected by a medical scare at a Wausau pool last week is back home.

Some 40 kindergartners and two adults were taken to hospitals Friday after spending time at a pool in a Wausau-area nursing home. Their symptoms included nausea, skin irritation and breathing problems.

Most were released in hours. Two girls were kept overnight and released Saturday.

Only one student remains in medical care. A nursing supervisor at St. Joseph's Hospital in Marshfield says the child was upgraded from critical to fair condition Saturday, and remained in fair condition last night.

Investigators think the emergency may have been caused by a noxious gas, possibly chlorine.

The nursing home is operated by North Central Health Care. Company executive Gary Bezucha says he's looking for answers to prevent something like this from happening again.