after noxious fumes filled the airplane making a number of passengers ill -- including a pregnant woman and a man who recently underwent heart surgery.

One of the 153 people on board told how he woke up unable to breathe. Other passengers also suffered breathing difficulty, as well as dizzy spells and chest pains.

It is believed the fumes were caused by a dental substance which leaked in a bag in the overhead luggage compartment.

A 44-year-old passenger, believed to be a dentist, was held by Police for questioning. He was escorted onto the plane to retrieve his hand luggage.

King Edward Memorial VII Hospital was put on full alert with dozens of off-duty doctors and nurses called in to work.

Police, six fire trucks and several US Navy and KEMH ambulances greeted flight 678 when it landed at about 4 p.m. The airplane was enroute from San Juan, Puerto Rico to New York's JFK Airport and was carrying mostly Spanish-speaking Puerto Ricans.

An incoming Delta flight was told to circle the Airport. Firemen dressed in special fire-proof outfits entered the plane before passengers were allowed to disembark.

About 20 hospital staff were outside KEMH Emergency Room to triage about a dozen passengers rushed to hospital.

Wearing oxygen masks, they all appeared calm.

Among them was a pregnant woman, some elderly folk, two teenagers and a man who recently underwent heart surgery.

Police meanwhile diverted traffic from the Berry Hill and Point Finger Road hospital entrances.

The pregnant woman was the only one detained but she was in satisfactory condition last night.

Patient Orlando Gonzales, who was on his way to New Yok for a holiday, said: "All I remember was I was sleeping and I woke up and couldn't breathe.'' He said the substance smelled like nail polish remover.

"A gentleman, a dental technician I think, had been travelling with a bottle of liquid which opened up in the luggage compartment,'' he said. "He found it was his and we all had to clear the area and put oxygen masks on.'' It is understood most of the passengers who were taken to hospital had not put their oxygen masks on properly. When they were lowered they did not pull them far enough down before putting them on.

The rest of the aircraft's passengers were treated at the Airport by hospital staff and taken to an Airport lounge for refreshments.

Emergency head Dr. Edward Schultz said he had been expecting around 90 sick passengers. But in the end only about 11 were admitted.

Nearly all the passengers were expected to leave the Island on another American Airlines flight last night.

It was not clear at first what caused the noxious fumes.

Though all those involved tried to assist the media by holding news conferences, at least three different accounts of the incident were given.

Airport officials said the fumes were caused by a leaking chemical. Government Information Services said a glue mixture was the culprit.

The Fire Service put it down to "careless transportation of a hazardous material''. And rumours of a fuel leak circulated at the hospital.

In the end, hospital officials and Police concluded a dental substance let off the fumes.

Nursing director Ms Eugenie Ible said the hospital first learned of the plane diversion around 3.30 p.m.

KEMH spokesman Mr. Bryan Darby said the US National Poison Control Centre had been contacted for help in treating the passengers.

A Police spokesperson said that once located, the "hazardous material'' which had leaked into the cabin area, was taken to the bathroom and later removed from the plane.

The spokesman said Police were conducting further inquiries into the incident.

The abandoned plane will be ferried back to New York later, Airport general manager Mr. Lawrence Lachapelle said. The substance evaporated and the area was washed down.

RUSHED TO HOSPITAL -- Emergency Room director Dr. Ed Schultz and nurses assist a pregnant Puerto Rican woman off an ambulance at King Edward VII Memorial Hospital. She was one of nearly a dozen passengers on an American Airlines flight who became ill after breathing noxious fumes.