OMAHA (DTN) -- Someone intentionally set a fire that led to the devastating ammonium nitrate explosion at West Fertilizer Co. in West, Texas, in 2013, officials with the Bureau of Alcohol, Tobacco, Firearms and Explosives announced during a news conference Wednesday.
The ATF said it has no suspects and is looking for help from the public, calling the act "criminal."
"After more than 400 interviews, a systematic fire-scene examination, the review of witness photos, videos and observations, as well as extensive scientific testing at the ATF Fire Research Lab in Beltsville, Maryland, the fire has been ruled 'incendiary' or intentionally set," ATF said in a news release Wednesday.
"All viable accidental and natural fire scenarios were hypothesized, tested and eliminated."
During a news conference Wednesday, ATF announced it is offering up to a $50,000 reward for information leading to the arrest of the person or persons "responsible for the fire and subsequent explosion."
Robert Elder, special agent in charge in the Houston division of the ATF, said during the news conference that investigators have stayed the course for the victims, which included volunteer fire workers.
"These individuals were people serving their community in a volunteer capacity," he said. "They are true community servants. They lost their lives serving their community and they deserve the best that we can give them."
ATF officials said Wednesday they will be releasing a final report on what laboratory tests found on materials gathered from the scene.
The Texas State Fire Marshal's Office provided the following statement when contacted by DTN: "We appreciate all ATF's work on this challenging case. Now that this has become a criminal investigation, we are mindful of the need to not compromise any aspect of the case and will be referring all questions to ATF."
Attorneys Steve Harrison of Waco's Harrison Davis Steakley Morrison, and Zona Jones of Beaumont's Provost Umphrey Law Firm, who represent many families pursuing civil claims related to the 2013 ammonium nitrate explosion in West, Texas, said in a statement the ATF's conclusions don't change their cases.
"There has been some misinformation about what ATF was announcing today," the statement said. "As McLennan County District Attorney Abel Reyna and ATF Agent in Charge Robert Elder stated, the ATF is looking at the cause and origin of the fire.
"The storage of the ammonium nitrate that exploded was not part of the ATF investigation. The ATF did not investigate what exploded, why it exploded or who knew that it could explode. All of that is the subject of civil litigation to be heard by a McLennan County jury."
Texas Attorney General Ken Paxton said in a statement justice will be served in the case.
"The devastating explosion in West impacted all Texans, especially those who lost loved ones that day, and forever changed that tightly-knit community," he said. "I applaud the diligence of the federal, state, and local agencies who are working tirelessly on this case and will assist in any way to ensure that the perpetrators responsible for this devastating act are found and brought to justice."
On April 17, 2013, at approximately 7:29 p.m., a fire was reported at West Fertilizer in West, Texas.
About 22 minutes later, a large explosion occurred, causing 15 deaths -- including 12 who were first-responders -- injuring 300 people and destroying more than 500 homes. The explosion left a crater about 93 feet wide and 12 feet deep.
The explosion that destroyed numerous homes, a nursing home and school near the facility occurred when 28 to 34 tons of about 60 tons of ammonium nitrate ignited in the warehouse on the West Fertilizer Co. property.
Investigators had been zeroing in on three possible causes of the fire at West Fertilizer: a potentially faulty 120-volt electrical system on the property, a golf cart that could have accidentally caught fire, or that the fire was intentionally started.
During the three years since the explosion, a Texas Fire Marshal investigation outlined a number of mistakes made by volunteers who arrived on the scene when the fire started.
Federal agencies investigating the disaster pointed to flaws in the way ammonium nitrate was stored at the facility.
The blast caused the fertilizer industry to take a closer look at ammonium nitrate and other chemical safety issues.
The ATF, along with the Texas State Fire Marshal's Office, Texas Rangers, McLennan County, Texas, district attorney's office and other agencies are asking for the public's assistance in the case.
Those with information are asked to contact Waco, Texas Crime Stoppers at 254-753-4357 or online at www.wacocrimestoppers.org
Todd Neeley can be reached at firstname.lastname@example.org
Follow him on Twitter @toddneeleyDTN
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