Four recent graduates of the Medical School have admitted to accidentally starting a 500-acre forest fire in a wilderness area northeast of Seattle in late June.

The men, who were on a hiking trip in the Cascade Mountains near Chelan, Wa., reportedly tried to dispose of toilet paper by burning it in the wooded area on June 27. Because of the dry spell plaguing the West coast this summer, the men's action ignited a blaze that took three days and about $500,000 to contain, said Wenahatchee National Forest spokeswoman Marti J. Ames.

The U.S. Forest Service is not releasing the names of the four until it decides whether to take civil action against them. The man allegedly responsible for igniting the blaze has been fined $100, the customary amount levied for starting a fire without a permit, said Benjamin Hull, a special agent with the Forest Service.

It remains unclear whether the Forest Service will ask the hiker to reimburse the government the $500,000 it took to put out the fire and the cost of damage to the forest.

The hikers reportedly told fire investigators on the scene that they had read experienced woodsmen always burned their toilet tissue. "It wasn't the thing to do," Ames said.

The fire, which was contained June 30, might have been extinguished more quickly if it had started in a more accessible location. Ames said the Forest Service could not get power equipment like bulldozers into the heavily wooded area and had to bring firefighters in by helicopter and boat.

The hikers apparently tried to extinguish the fire themselves before being boated to safety across Lake Chelan, where a Forest Service official in a guardhouse had spotted the smoke. "I imagine it was tense for [the hikers], but they probably didn't have much of a chance," Ames said.

The blaze scorched a considerable portion of the Lake Chelan-Sawtooth Wilderness Area, about 90 miles northeast of Seattle.