A December 2006 EPA rule reduced the amount of pollution information reported under its Toxics Release Inventory Program. Previously, companies that released less than 500 pounds of certain substances did not have to report details about what they released. The 2006 rule bumped that amount tenfold, allowing companies to release up to 5,000 pounds before filing detailed information.

When it proposed the new rules, the EPA said the new reporting guidelines would represent only a small portion of the total chemicals reported to the public.

But a Government Accountability Office report released in November 2007 found that more than 3,500 facilities nationwide would no longer be required to report detailed information about their toxic releases.

Reversing these rules will be a huge task for the new administration, Dalglish said. But this reversal should start on day one: “Saying in his inaugural speech that this will be the most open and transparent government in history will make it easier for agencies to come in and do it.”

Jennifer LaFleur, ProPublica is a reporter for ProPublica, an independent, non-profit newsroom that produces investigative journalism in the public interest.