WEST (CBS 11 NEWS) – More than two weeks since the deadly fertilizer plant explosion in West, Texas, and the Sullivans are still cleaning up.

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Richard Sullivan was on his lawnmower when it happened. His wife was in their home.

“I was blown off, I don’t remember that happening to me,” said Sullivan. “Susan was in the house, and it knocked her down twice.   She had to crawl out.”

State and federal investigators are looking into whether the ammonium nitrate stored at the plant caused the blast, that killed 14 people, including first responders.

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Experts say by itself, ammonium nitrate shouldn’t explode — unless, they say, there’s an accelerant, or if it reaches 450 degrees.

Material Safety Data Sheets for ammonium nitrate show that it “…May explode or detonate under confinement and high temperatures…” and that it “…explodes more readily if contaminated with organic materials or other fuels.”

Investigators are trying to determine if that played a role.

The city’s Mayor Tommy Muska told CBS 11 he didn’t realize the plant could blow up.

CBS 11’s Jack Fink asked McLennan County’s Emergency Management Coordinator the same thing yesterday.

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“If you’re asking me sitting here right now?  No,” he said.

The material safety data sheets have special firefighting procedures, saying firefighters should abandon their efforts for any large fire or fire engulfing confining containers, and quickly evacuate all personnel to a distance 2500 feet away.

The Sullivans estimate they live just a thousand feet away from the plant and say before the blast they were not told to evacuate.

While investigators have lots of questions, experts we spoke with question the guidelines for storing ammonium nitrate.

The National Fire Protection Association code only requires an automatic sprinkler system when there are more than 2,500 tons of the chemical being stored.

The most ever stored at West was 270 tons, so a sprinkler would not have been required.

According to Muska, the fire department did do on-site inspections at the fertilizer plant, but he was not aware of any fire training exercises at the facility.

CBS 11 unsuccessfully attempted to contact West’s fire chief.

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