When American swimmer Alex Meyer pulled out of the men’s 25-kilometre race at the world championships before the start yesterday, he did so with good reason: his friend and teammate Fran Crippen died in a race run in similarly warm water last year.

As the open water race got underway and one swimmer after another called it quits because of the warm water, Meyer questioned why FINA, the world swimming body, was risking a repeat of last year’s tragedy.

“It’s like, did you not learn your lesson? Do you not remember what happened last time?” he said.

The men’s and women’s races were moved up to a 6 a.m. start in an attempt to stage them in cooler conditions. But the water was already 30.5 Celsius (87 Fahrenheit), just under the suggested “unsafe” point of 31 Celsius (88 Fahrenheit).

As the morning wore on, the water temperature reached 31 degrees and the sun began beating down on the course. The air temperature was 32 Celsius (90 Fahrenheit) with 68 per cent humidity by the time the race finished.

By that point, 10 of the 29 men who started the race had quit, as had four of the 21 female starters.

Defending men’s champion Valerio Cleri of Italy left the water just after four hours, saying it was “too hot and too dangerous” to continue.

“There’s not enough attention on the athletes,” Cleri said. “There should not have been a race here. The jury was irresponsible.”

His teammate, Edoardo Stochino, quit about 50 minutes later and was taken away on a stretcher as officials poured cold water over his chest. He was checked out and returned to the venue a short time later.

Safety became a major concern in open water swimming after Crippen, a six-time US national champion, died in October near the end of a 10K World Cup event in the United Arab Emirates. No one noticed him slip beneath the surface and his body was not found until two hours after the race.

Following the race, FINA issued a new recommendation that races should not be conducted when water temperature exceeds 31 Celsius (88 Fahrenheit).