KNIGHTDALE - Veteran firefighter Goley Boggs was eating his Egg McMuffin Sunday morning, talking to friends, when something in the air caused him to choke and cough.

"Everybody in here started coughing and choking and everything," said Boggs, who was at the McDonald's on Knightdale Boulevard. "I looked at them and said 'We need to get out of here.'"

Boggs told a waitress to call 911 and then started evacuating the restaurant. "I told everybody to go out and stay together."

About 30 people were treated by EMS units on the scene and six, including Boggs, were taken to the area hosptials. Police on Monday were still trying to determine the cause of the colorless, odorless gas that filled the restaurant about 10 a.m., Sunday. McDonald's manager Maria Aguiliar said a customer reported that someone put pepper spray on a hand dryer in the bathroom and turned it on, but that has not been confirmed.

As of Monday night, Knightdale Public Safety Director Shawn Brown said several customers reported seeing a cloud around the bathrooms, but that the cause had not been determined. Brown said police plan to looked at toxicology reports of patients who agreed for the hospital to share them with police. He said that could show what substance restaurant patrons were exposed to. Brown said police also plan to look at surveillance video.

"We're trying to investigate everything and follow up on all possible leads," he said.

By 2:30 Sunday, the McDonalds was open for business after receiving clearance by the Wake County Health Department, Brown said.

Boggs said after customers and employees got out of the building, police arrived. He and an officer returned inside to check the building.

Boggs, a firefighter of 21 years, started working the emergency with the fire department when firefighers arrived.

"By that time it got to me," said Boggs. "It kept getting worse. My heart rate took off.My lungs felt like they were itching and burning....When I got outside and started getting sick, I wasn't no good any more to anybody."

Boggs said EMS took him to Rex Hospital where he was treated with a breathing machine and medicine, and monitored.

"After they decided the real emergency was over, the doctor said I could go home and for me to rest today and take some medicine," he said. "I've still got an itchy, scratchy throat."

Boggs said the restaurant was full when the substance was released. "A couple of women out there were crying. I guess they were just scared. There was a total of about 30 people,"he said. "Something was in the air. It just got us all."

A Raleigh hazardous materials team swept the restaurant with their equipment but didn't find anything unsual, said Knightdale Fire chief Tim Guffey. In addition to Raleigh, Knightdale public safety, Eastern Wake EMS and Wake County EMS were dispatched to the McDonald's.