ATHLETICS:MARATHON WORLD record holder Haile Gebrselassie will not compete in the Olympic marathon because he fears Beijing's air pollution would damage his health.

The Ethiopian runner, who suffers from asthma, said he would still compete in the 10,000 metres at the August Games.

"The pollution in China is a threat to my health and it would be difficult for me to run 42 kilometres in my current condition," he said.

"But I am not pulling out of the Olympic event in Beijing all together. I plan to participate in the 10,000."

Pollution is a major issue facing Beijing in the run-up to the Games.

International Olympic Committee (IOC) chief Jacques Rogge said last year that events such as the marathon could be rescheduled if contingency measures did not have the desired effect.

The IOC would not comment on Gebrselassie's decision, but a spokesperson said the committee were satisfied with pollution levels taken during test events.

"We have received new data on pollution and air quality and we are currently analysing them," IOC spokesperson Emmanuelle Moreau said. "From the test events that have taken place so far the levels have been satisfactory."

Gebrselassie called on China to deal with the problem, saying that pollution "would be a hazard to athletes, seriously affecting their performances".

Dube Jillo, technical director of the Ethiopian Athletic Federation, said as far as his federation were concerned Gebrselassie was expected to compete in the Olympics.

"Whether he runs in the marathon or 10,000 . . . would be his own choice."

Rogge told reporters last November in New York that a monitoring system would be set up in Beijing to gauge whether air pollution warranted delaying events.

Events that involve endurance, such as the marathon or cycling, could be delayed for a few hours or until another day, Rogge said.

"During a marathon for more than two hours, riding a bicycle race for five to six hours - that could be a danger hazard and then we would postpone the race," he said at the time.

Meanwhile, controversial British sprinter Dwain Chambers is considering launching a legal challenge against a British Olympic Association (BOA) bylaw banning drug offenders from competing at the Games.

Despite the BOA's insistence they can justify their rule, Chambers' legal team feel they can pull off a victory in a case which could go directly to the High Court rather than through the Court of Arbitration for Sport in Lausanne.

But Chambers, who will be meeting his lawyer Nick Collins this week, still has worries over how he could fund his career without receiving an income from the sport.

He also has to continue repaying the approximately €150,000 debt for prize money earned during the period he was cheating to the International Association of Athletics Federations.

"There may not be a comeback," said Chambers - who won €15,000 for his joint second with Kim Collins, behind Olusoji Fasuba, in the World Indoor championships in Valencia, Spain, last week.

"As I said earlier, this is my Olympic Games. I have my medal; I'm happy - and let's hope there's a chance for me to move forward.

"If not, then I'll pursue a career elsewhere."