President Orders Review of Chemical Plant Safety President Obama on Thursday ordered federal agencies to review safety rules at chemical facilities in response to the April explosion at a Texas fertilizer plant that killed 15 people. Mr. Obama's executive order asked agencies to identify ways to safely store and secure ammonium nitrate, the explosive chemical that investigators say caused the blast. Agencies are also being told to determine whether additional chemicals should be covered by federal regulations. While the explosion is still being investigated, preliminary findings have been presented to Congress. A report sent to the Senate Environment and Public Works Committee in June showed that the decades-old standards used to regulate fertilizer chemicals are far weaker than those used in other countries. The report concluded that the safety of ammonium nitrate fertilizer storage "falls under a patchwork of U.S. regulatory standards and guidance - a patchwork that has many large holes."