LITTLE ROCK—More than 30 people at a state-affiliated health clinic were hospitalized Thursday with nausea and dizziness, and a few complained of uncontrollable drooling. Officials were checking whether the illnesses could be traced to an exterminator’s visit early this week.

Health officials initially said all of the ill were employees, but said later Thursday that two patients were among those sickened.

As a precaution, a hazardous materials unit from Camp Robinson was headed to Fayetteville to conduct tests at the Washington County Health Unit, said Arkansas Department of Health spokeswoman Ann Wright.

All but six of the 31 who fell ill were released from area hospitals by Thursday afternoon. None of the illnesses were deemed life-threatening.

“We always have to hold out the possibility that someone brought something in,” said John Gibson, county administrator. “I would hope that’s not the case. The Health Department is a pretty benign organization that helps people. We’ve never received any threats, but you have to hold out all possibilities.”

The Washington County Regional Medical Center said the 26 people it treated had been exposed to an “unconfirmed source.” There was no sign of exposure or illness anywhere but the clinic, Wright said.

“The unit is still closed. Our primary concern is for our employees and their safety, and we hope we can get back in business quickly,” she said.

Rick Johnson, the health unit’s administrator, told The Morning News newspaper in Springdale that the outbreak moved among the staff too quickly to have been a flu or other communicable illness.

“There’s definitely an external factor at work here,” Johnson said.

Gibson said state and local officials helped evacuate the unit, which offers health education and various services, including vaccinations.

“We’ll find the cause and fix it right away,” he said.