By ROBERT E. ROBERTS

Something big happened in Washington, D.C., this week - something with the potential to move the earth - actually to move contaminated dirt and rock, and a lot of it, in communities throughout the Rocky Mountain West.

You may not have noticed, but on Wednesday the Environmental Protection Agency released a “Model Good Samaritan Agreement” for its regional offices to use to encourage volunteer efforts to clean up contaminated mine sites. This action is a long-awaited policy tool that will help accelerate the pace of environmental progress in watersheds across the West.

There are an estimated 500,000 abandoned mines nationwide, mostly hardrock sites, and most in Western states. These sites - piles of crushed rock and barren areas tinted with telltale shades of orange, yellow and red - litter the mountainsides in historic mining districts. They often contain harmful metals such as lead, arsenic, cadmium or zinc. When it rains, and when snow melts, the acid runoff they produce can render local rivers and streams lifeless.

EPA and its partners have worked on this problem for decades, and we have been able to clean up many of the biggest and worst mine sites by making the companies responsible for pollution pay for cleanup actions. But for most of these sites - called “orphan sites” - the company that operated the mine is long gone. There is no responsible party to fund the cleanup.

An unintended consequence of the Superfund law is that volunteers who want to clean up such sites face the possibility of taking on responsibility for all the past and future pollution. These Good Samaritans have nothing to do with the pollution that has already occurred or will occur. And they certainly have no interest in contributing to further pollution. But the size of the potential liability they may take on by working on the site makes most of them unwilling to take on such projects.

EPA's release of the Model Good Samaritan Agreement is a big step toward eliminating that obstacle. This tool will allow Good Samaritans who want to work on orphan mines to enter into agreements with EPA that minimize the Superfund law liability concerns. Beneficial cleanup projects, many with blueprints that have been sitting on shelves for years, now have the green light to proceed.

As one watershed group leader from Colorado exclaimed upon hearing the news, “It feels like someone has taken my handcuffs off.”

President Bush and the EPA are clearing legal roadblocks to help protect America's watersheds. While additional obstacles for Good Samaritans remain, legislation that will provide further relief for mine cleanup projects is now pending in Congress. Our continued progress on this issue is good news for everyone who cares about clean water.

Robert E. Roberts is regional administrator of the U.S. Environmental Protection Agency, Region 8, which includes Montana.