As a congressional investigation revealed this week, the EPA's regulation of toxic chemicals like dioxin has been corrupted by interference by the White House. But this case is stunning:

For the past year, Gade has been locked in a heated dispute with Dow about long-delayed plans to clean up dioxin-saturated soil and sediment that extends 50 miles beyond its Midland, Mich., plant into Saginaw Bay and Lake Huron. [...]

Though regional EPA administrators typically have wide latitude to enforce environmental laws, Gade drew fire from officials in Washington last month after she sent contractors to test soil in a Saginaw neighborhood where Dow had found high dioxin levels.

She said top lieutenants to Stephen Johnson, the national EPA administrator, repeatedly questioned her aggressive action against Dow, which long ago acknowledged it is responsible for the dioxin contamination but has resisted federal and state involvement in cleanup plans.

When Johnson appointed Gade to her position in 2006, he praised "her impressive environmental career," saying, "Mary is well-prepared to lead the Agency's largest regional office."

Update: Mary Gade was a loyal Republican and adviser to Bush in 2000:

I'm a Republican and a supporter of Texas Governor George W. Bush. I believe Governor Bush in two terms has put together a stronger bipartisan record on conservation and the environment than Al Gore has in twenty-plus years in Washington, D.C., precisely because Bush puts action and results above talk and posture.