Should snowmobiling be allowed in national parks? The government has decided that, with new restrictions, snowmobiling can continue at national parks. Environmentalists say it's harmful. (opinion).

YES The winter in Grand Teton and Yellowstone national parks is raw and powerful. Steam rises up in great clouds from hot springs bubbling to the surface in the subzero cold. Herds of elk and bison wade through the heavy snow. Here you can see the world as it has been for thousands of years.

Our challenge is to make this experience available to people now, while ensuring that it remains so long into the future. As part of an agreement signed a year and a half ago to settle a lawsuit, the National Park Service has re-examined the issue of whether snowmobiles should be entirely banned from these two parks. A major factor in this review has been the substantial improvements made in snowmobile technology. New machines now in production are quieter and 90 percent less polluting.

In light of this new technology, the park service has developed a balanced plan that would allow limited snowmobile use, and still preserve the natural resources of our national parks. Snowmobiling provides a unique way to experience the parks, and the money these people spend is an important contribution to local economies.

The plan would ban older, dirtier snowmobiles, and would set, for the first time, strict limits on their numbers. During hob days, when the number of snowmobiles is highest, the number of machines entering the parks would be cut from 1,650 a day to 1,100. And these will be vastly cleaner machines. Also, all snowmobilers allowed in the parks must have a trained guide and stick to groomed roads, so that wildlife would be protected.

To be sure this plan works, monitoring stations would be established around the parks to keep careful records on air quality, water quality, noise, and wildlife. These data would tell park managers if the resources were being harmed and allow them to adjust the number of snowmobiles accordingly.

The National Park Service is dedicated to preserving our parks and to helping Americans understand and enjoy these magnificent places. Banning the old snowmobiles, and allowing limited numbers of cleaner, quieter machines does both.

--RICK FROST Communications Director, Intermountain Region National Park Service

NO Snowmobiles should not be allowed in our national parks, because they are too loud and produce air pollution dangerous to people and to the parks. Besides, snowmobilers have plenty of other places to go. Yellowstone National Park, for example, offers less than 200 miles of trails for snowmobiles, while the three states that surround the park have 14,000 miles of trails.

The snowmobile industry claims it has a new type of engine that is quieter and less polluting than the current ones. But a federal report shows that even the new engines are noisy and produce unhealthy levels of air pollution.

Each year, about 70,000 snowmobiles roar through Yellowstone, each one producing more smog-forming pollution in an hour than a modern car does in a day. In an average winter, snowmobiles in Yellowstone leave behind as much pollution as cars would in 68 years. Park rangers have to wear air filters to keep from being sickened by snowmobile fumes. Wildlife also suffers. Snowmobiles follow trails that bison and other animals use to avoid deep snow, frightening the animals and forcing them to move around when they should be looking for food.

We have several concerns about the Bush administration's plan to allow a controlled number of snowmobiles in Yellowstone. The plan would cap at 1,100 the number of snowmobiles allowed into the park on an average winter day. But that "cap" is more than the current daily average of 840 snowmobiles. The plan also encourages snowmobiles to enter the park by gates that now receive little use, which would spread out the snowmobiles' impact, rather than lessening it.

The only winter transportation system suitable for national parks is the snowcoach--a sate, less-polluting alternative. Driven by guides, snowcoaches carry as many as 10 passengers and produce less air and noise pollution. In Yellowstone, they would reduce the number of winter vehicles by about 85 percent.

Our national parks require the utmost protection if we wish to preserve their grandeur. It's time to keep snowmobiles out.

--THOMAS KIERNAN President National Parks Conservation Association