The father of someone who fell ill on a flight from the Dominican Republican to Edmonton says a drug could have been slipped to one or more of his relatives before they left the Caribbean country yesterday.

Eight people were taken to hospital in Florida late Tuesday night after the Air Transat flight they were on was diverted to Fort Lauderdale. The U.S. Center for Disease Control (CDC) found that the passengers were not suffering from any airborne illnesses.

The remaining passengers, about 250, and nine crew members were kept on the plane throughout the whole incident.

Terry Rollie, whose children and relatives were among the sick, said a date rape drug may be responsible.

Rollie said doctors have told him that they found traces of the drug GHB in a female relative's test results. The hospital has not confirmed that, but Rollie said he suspected something was wrong even before they boarded the flight.

"We figured (she) was sick before we even left the resort," he said. "We figured she was drunk when we left the resort, but it wasn't like that."

Rollie said he had suspicions drugs may have been involved.

"We thought there was something slipped in a drink," Rollie said.

Rollie said his brother in-law, his wife, and two of their kids also got sick.

Other passengers said they were also suspicious about what was behind the illnesses.

"They seem drugged," Krista Dorton said. "That was our first take on it."

Another passenger, Allison Zimmerman, said, "There was one girl, she was just crying, hysterically crying."

Other passengers began to worry when it appeared that the sick passengers' symptoms spread to others, seemingly through touch, after the plane had taken off.

"It was like, OK, what do people have? Can we get off now," said Kim Murdoch.

The family members apparently all ate together yesterday afternoon before boarding the flight. But not everyone at the restaurant got sick.

Once the family members were taken off the flight and sent to hospital, the plane they were on was quarantined and inspected by the CDC. The quarantine was lifted early Wednesday morning and the plane arrived in Edmonton at 8:30 a.m. without the sick passengers, who have since been released from hospital.

Officials at Edmonton International Airport said no one else became ill once the flight resumed, and the regional health authority cleared the plane once it landed in Canada.