"The government has no way of fully knowing which U.S. chemical facilities stock ammonium nitrate, the substance that exploded last year at a Texas fertilizer plant and killed 14 people, congressional investigators say. Outdated federal policies, poor information sharing with states and a raft of industry exemptions point to scant federal oversight, says a new report obtained by The Associated Press.

The report found regulatory gaps in environmental and worker protections and urged broad changes to U.S. safety rules. President Barack Obama pledged to stiffen enforcement following the explosion on April 17, 2013, in West, Texas.

Without improved monitoring, federal regulators "will not know the extent to which dangerous conditions at some facilities may continue to exist," concluded the report by the Government Accountability Office."

Hope Yen reports for the Associated Press May 20, 2014. [2]