The Environmental Protection Agency has displayed a lack of urgency in the wake of a deadly Texas fertilizer plant explosion and must regulate potentially explosive chemicals immediately, legislators said Thursday.

The Chemical Safety Board, one of several federal agencies investigating the April explosion at the West Fertilizer Co. that killed 15 people, presented its preliminary findings to the Senate Committee on Environment and Public Works. It reported that the decades-old standards used to regulate potentially dangerous fertilizer chemicals are far weaker than those used by other countries.

“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,” according to the report presented to the panel by Rafael Moure-Eraso, the board’s chairman.

The board, which has no regulatory authority, recommended in 2002 that the EPA and the Occupational Safety and Health Administration add reactive chemicals such as ammonium nitrate to the list of substances they regulate. That never happened, and the risk management plan that the plant in West was required by federal law to fill out focused exclusively on the potential for a leak of anhydrous ammonia, another fertilizer chemical it stored and sold.

Sen. Barbara Boxer, a Democrat from California who chairs the committee, said new legislation was not necessary to permit the EPA to begin regulating the safe handling of ammonium nitrate and other hazardous chemicals.

OSHA, according to other experts who testified, already requires ammonium nitrate to be stored separately from other combustibles and in a room with fireproof walls, but the agency had not inspected the West plant since 1985. The facility was not in compliance, and if it had been, the accident could have been avoided, testified Sam Mannan, a professor and expert on process safety from Texas A&M University.

About 30 tons of ammonium nitrate stored at the plant detonated about 20 minutes after the fire was reported, causing a blast so massive it registered as a small earthquake, flattened swaths of the small town of West and killed 10 emergency responders. The firefighters, the Chemical Safety Board reported, were unaware of the dangers of the chemical that is often used as a cheap alternative to dynamite in mining operations and has been used in terrorist bomb attacks.

The testimony was punctuated by Boxer’s sharp rebukes of the EPA. She vowed at the end of the hearing to work with the agency “much more closely than they’d like” to ensure the regulations are updated, and quickly.

Boxer demanded that Barry Breen, the agency’s deputy assistant administrator of the Office of Solid Waste and Emergency Response, provide a timeline for updating the regulations. She pointedly disagreed with his assessment that the board’s 2002 recommendations were not clear.

Breen’s testimony provided an overview of the chemicals included in the EPA’s risk management program, but did not directly address the explosion in West.

“That was the most vague testimony I’ve ever heard,” Boxer told him. “I don’t sense in your voice any type of shock or desire to move forward … I don’t detect any urgency.”

The board noted that a 1985 review of the dangers of ammonium nitrate stated it shouldn’t be stored near a source of heat or other combustibles.

“This principle has not been fully adopted across the U.S., and was not implemented at West Fertilizer,” Moure-Eraso wrote.

The Chemical Safety Board investigates major industrial and chemical accidents, including the 2012 oil spill in the Gulf of Mexico. Its goal is to make recommendations that would help avoid similar incidents.

The plant in West was built in 1961, on what was then the outskirts of the rural farming community. Over the years, residences sprang up nearby, along with a nursing home and several schools. All were damaged or destroyed in the blast. The board said had the explosion occurred during the day, when students were still at school, the outcome would have been worse.

Mannan and Paul Orum, a consultant with the Coalition to Prevent Chemical Disasters, said regulations should require a certain distance between critical infrastructures and facilities that store and handle hazardous materials.

Some agencies do have other rules on ammonium nitrate, but none apparently applied to the facility in West.

The Bureau of Alcohol, Tobacco, Firearms and Explosives has rules for using ammonium nitrate as an explosive. And the U.S. Department of Homeland Security’s regulations are meant to ensure the chemical does not land in the hands of criminals or militants.

Codes written by the National Fire Protection Association are also not strong enough, the CSB states. For example, the codes allow the chemical to be stored in wooden bins, even though other countries, including the United Kingdom, instruct the chemical should be placed in non-flammable containers, preferably concrete.

Either way, West Fertilizer was not required to comply with the fire code. They are merely recommendations, and Texas has not adopted a statewide fire code. Some smaller counties are prohibited by state law from adopting their own.

Federal agencies must “review and improve the comprehensive safety oversight of ammonium nitrate fertilizer distribution. The time for that effort is now,” the CSB concludes.

(AP)