[Editor’s Note: This is part of a series of stories in which the ABC15 Investigators and the Arizona Center for Investigative Reporting collaborated to explore how Arizona regulates the storage and transportation of hazardous chemicals across the state.]

By Brandon Quester, AZCIR | Lauren Gilger and Maria Tomasch, ABC15

PHOENIX – Government agencies across the U.S. can’t regulate ammonium nitrate, the hazardous chemical compound that detonated in West, Texas, killing 15 people and injuring hundreds more, a congressional investigation has found.

Emergency management agencies at the local, state and federal levels don’t know how many facilities in the U.S. store the hazardous chemical. A patchwork of outdated regulations, lack of communication between agencies, and a series of exemptions exist for reporting storage of ammonium nitrate, the U.S. Government Accountability Office report stated, which was publicly released May 21.

This combination of government deficiencies prohibits officials from regulating the substance and heightens the risks to communities surrounding the facilities that store ammonium nitrate.

A recent joint investigation by the ABC15 Investigators and the Arizona Center for Investigative Reporting found the same absent regulatory oversight of ammonium nitrate in Arizona, mirroring the findings of the congressional report.

ABC15 and AZCIR reporters found that Arizona’s largest known ammonium nitrate storage facility houses more than 80 million pounds of the chemical compound but didn’t share chemical inventory reports, as is required by law, to local first responders.

Reporters also found that Arizona emergency response personnel don’t know how many facilities are storing the dangerous chemical here.

The GAO report said significant gaps exist in federal regulation of ammonium nitrate. The primary agencies responsible for overseeing the substance are the Department of Homeland Security, the Environmental Protection Agency and the Occupational Safety and Health Administration.

Federal investigators concluded that without increased coordination between federal agencies, “identifying facilities with ammonium nitrate for purposes of increasing awareness of the hazards and improving regulatory compliance will remain a challenge.”

The findings also state that if additional regulations are not implemented, the communities surrounding ammonium nitrate storage facilities — and the workers within the companies — will not be adequately protected from the risks the chemicals pose.

President Barack Obama issued an executive order in August 2013 to improve the safety and security of chemical facilities across the U.S., which was prompted by the explosion in West, Texas. The order created a national working group that is tasked with examining current laws and to make recommendations on how to improve the safety of storing and transporting hazardous materials in the U.S.

The GAO report mentions this executive order and suggests that the group implement methods to improve data sharing among federal and state agencies.

The recommendations from the working group are expected to be released early this summer.