Protests have greeted plans to cut short part of an Ironman challenge which starts in Wigan borough.
Promoters of Ironman Bolton, which begins at Pennington Flash and travels through Leigh, Parbold and Standish, have cut the cycling leg by 17 miles, due to the wildfires which have gripped the Winter Hill area.
This has reduced the ride from 112 miles to 95 miles, avoiding the immediate vicinity of the moorland incident, which has been smouldering for a fortnight.
But competitors, who paid a £400 entry fee and have trained for months for the popular triathlon have besieged the organisers' Facebook account, urging them to reconsider.
Ian Hoffman, from Bristol, said: "I'm sorry Ironman but this is disgusting. You built your entire brand around the challenge of becoming an Ironman for which you plaster the distances all over the place.
"Then take away the opportunity to do that on six days notice. After 30 weeks of early weekend starts, battling through wind, rain, snow, hail, three beasts for the east, missed events, poor sleep, essentially structuring your life around the commitment to this challenge to have it taken away this close is crushing."
But Craig Green, from Wakefield, added: "They have so much planning to do, so much deliberation with council and locals to ensure the event is a go. Let alone the safety aspect of smoke inhalation."
Earlier this week the Wigan Post highlighted the fact that toxic blue-green algae, harmful to the skin, was affecting Pennington Flash, which hosts a 2.4 mile swim to kickstart the event.
In response to criticism, Ironman organisers have been contacting athletes who have complained.
One e-mail read: "The wildfire situation is beyond our control. Athlete safety will always be our priority and under these circumstances, the changed course is the only way in which the race is able to safely go ahead with the support of local authorities, police and fire service, whilst also considering the impact on the local communities affected by the event."
An Ironman spokesman added: "We tried everything we could but it came down to the police and the council. We understand the frustration, we know it’s not ideal.
“[But] it’s the only way to make it work without cancelling the whole race."