BILLINGS, Mont. Seven former National Park Service directors say raising the limit on the number of snowmobiles allowed in Yellowstone National Park would harm the park's environment.
In a letter released Monday, the directors wrote that increasing the number of snowmobiles allowed in the park would "undercut the park's resurgent natural conditions" and reverse air quality improvements.
The letter comes as park administrators are set to release today their latest plan for snowmobiles at the nation's original national park.
The former directors sent the letter to U.S. Interior Secretary Dirk Kempthorne, and Park Service spokesman David Barna said Kempthorne will respond in the coming days. Barna added that a final policy will not be adopted until after a 60-day public comment period.
Snowmobile use at the park has fueled years of legal wrangling. Pressure to allow more of the vehicles has come from snowmobilers, nearby communities eager for winter tourists and the advocates' congressional allies.
A draft version of the latest winter-use plan recommends allowing up to 720 snowmobiles a day. The cap would be consistent with temporary rules in place the last three winters. Those rules expired last week.
The proposed plan would also extend rules requiring that hired guides accompany snowmobilers and that the machines have less-polluting engines.
During the three winters, actual snowmobile traffic averaged only about 250 machines a day, a sharp drop from the historical daily average of 765.
The letter said allowing snowmobile numbers to return almost to historical levels would "radically contravene both the spirit and letter" of Park Service policies and contradicts the service's draft environmental impact statement that found snowmobile noise and exhaust would increase.
The directors did not include Fran Mainella, who resigned last year. Ethics rules prohibit her involvement, said a spokesman.