Hydrofluoric acid is a deadly chemical used in many petroleum refinery operations. When it escapes, it becomes a gas that can race long distances and kill people who inhale it. Safer alternatives are available to refineries. At the urging of petrochemical companies, Congress and the executive branch have kept the dangers largely secret from the at-risk public, so there has been little pressure for refineries to make their operations safer. In a joint investigation the Center for Public Integrity and ABC News found that worst-case scenarios filed by just 50 refineries showed some 16 million Americans at risk from accidental or intentional hydrofluoric acid releases.
Jim Morris and Chris Hamby report February 24, 2011, for the Center for Public Integrity . Matthew Mosk and Brian Ross of ABC News contributed to this story.  Laurel Adams, Amy Biegelsen, and Jeremy Borden of the Center for Public Integrity also contributed. A version of this story will appear on ABC’s Nightline news program Feb. 24. The story is part of an ongoing series: "Hidden Fears -- The Hidden Hazards of U.S. Refineries."