(U-WIRE) LAWRENCE, Kan. — Two students fainted and one fell ill in an unexplained incident at about 8:30 a.m. Wednesday in a Malott Hall chemistry lab. All three students declined medical treatment.

Adam Yarnell, Wichita junior, and Megan Weatherly, Overland Park, Kan., junior, were at the front of room 2028 Malott taking notes for their introductory chemistry class.

Yarnell got up from his desk and began to leave the room as if he were feeling sick, said Andrew Miller, Swansea, Ill., junior, who was near Yarnell at the time. Miller said Yarnell fell face forward on the floor.

Miller went to help Yarnell and felt nauseated.

"I started getting sick, so I got up and left the room," Miller said. "When I came back everyone was in the hall."

After Yarnell fainted, the lab's teaching assistant, Jason Sanders, Derby senior, made sure he was all right. He then went to get the lab director for help.

Sanders said when he and the director came back, Weatherly fainted as well.

Weatherly said she was writing when Yarnell fell. When she looked up to see what had happened, she began to feel ill.

"I don't know if I was scared for him or if I brought my head up too fast, but I started to feel really dizzy," she said.

When the dizziness didn't fade, Weatherly said she went back to her seat to sit down but didn't feel any better.

"I started feeling really hot and took off my sweatshirt," she said. "Then I just passed out."

Weatherly fell into her lab partner's lap.

Sanders said that at first he thought the problem was exclusive to Yarnell.

"But when Megan went down and Andrew felt sick, I realized it was something wrong with the room," he said.

Sanders said that was when he decided to evacuate the room.

Douglas County Fire and Medical and the University of Kansas' department of environmental health and safety responded to the scene, but neither found any hazardous gases or material.

"There is nothing in this room that would be out of what would be expected in a lab. We didn't find any airborne chemicals at all," said Mike Russell, director of the department of environmental health and safety.

Russell said he could not explain what caused the incident.

It is possible that a gas could have come up through the sink drain both students were standing by and dissipated before professionals could detect it, he said. But, he said, those types of emissions tend to smell like a sewer. No one in the room reported seeing or smelling anything strange.

Russell said it could also just be a bizarre coincidence. He said if the room was warm and people were moving their heads too quickly, they could have lost their balance and felt momentarily ill.

Russell and Sanders agreed the three chemicals -- potassium permanganate, iron (II) chloride and phosphoric acid -- used in the lab that day could not have caused the reaction.

"It's all very benign chemistry," Russell said. "The biggest thing we would have to worry about is skin contact that could possibly lead to irritation."

Lab classes continued in the room throughout the day without incident.

Students who had felt ill said they were better after leaving the room. They said they planned to continue the day as normal and would be at a test scheduled for the class later that evening.

"Maybe I can get some extra credit out of this," Weatherly said.

- Abby Mills