One month on, arson remains a focus for Texas blast investigators

But they cannot eliminate plant's electrical system or electric cart as potential causes

The cause of a fire that triggered a massive explosion at a West, Texas fertilizer plant has been ruled undetermined, and investigators have not eliminated the possibility that the fire was set intentionally, state and federal officials say.

Robert Champion, a special agent in charge at the Bureau of Alcohol, Tobacco, Firearms and Explosives, said that while authorities could not rule out arson, they also could not eliminate the plant's electrical system or a golf cart at the plant as potential causes.

The West Fertilizer Co facility, which supplied fertilizer to area farmers, exploded on 17 April about 20 minutes after a fire was reported at the plant. The blast - actually, what officials described Thursday as a pair of blasts separated by milliseconds, - killed 14 people and badly damaged a residential area including an apartment building, nursing home and school.

The investigation, which cost the ATF more than $1 million, involved pursuing 280 leads, interviewing 500 people, and sifting through 300,000 pounds of corn by hand to collect evidence, Assistant State Fire Marshal Kelly Kistner said.

"It's like taking a large puzzle, putting it on the coffee table and trying to put the pieces back together, but you don't know if the pieces are all there to begin with," Kistner said.

The scene investigation is complete, but the overall probe into the fire is continuing, State Fire Marshal Chris Connealy said. The fire marshal's office is also investigating the deaths of the first responders.

Most of the dead were firefighters and paramedics who responded to the initial fire. Some 200 people were injured.

"This was one of the worst events among first responders," Connealy said. "We wanted to leave no stone unturned to give this community some aspects of closure."

The plant stored anhydrous ammonia, a liquid fertilizer, as well as ammonium nitrate, a dry fertilizer that can ignite in certain conditions. Ammonium nitrate was an ingredient in the device used in the 1995 Oklahoma City bombing.

Investigators had previously ruled out possible causes including the weather, natural causes, a fire within the ammonium nitrate bin, a rail car containing ammonium nitrate and anhydrous ammonia - another fertilizer component.

Investigators believe the fire started somewhere in the 12,000-square-foot (1,100-square-meter) fertilizer and seed building. They confirmed last week that ammonium nitrate stored at the plant detonated in the explosion.

"As temperature increased, the pressure increased, which made the ammonium nitrate change states and its sensitivity to shock increase," Kistner said Thursday. "A portion of ammonium nitrate caused the first explosion."

The small explosion produced enough heat and shock to cause the remaining ammonium nitrate to massively explode, he said.

Between 28 and 34 tons of ammonium nitrate exploded at the plant, and an additional 20 to 30 tons were in the building but did not explode, Kistner said. In addition, there were 100 tons of ammonium nitrate in a rail car that did not explode, though the rail car itself "was a victim of the explosion," Kistner said.

"To put this in a different perspective, the ammonium nitrate that exploded was equivalent to approximately 15,000 to 20,000 pounds of TNT," Kistner said.

State officials last week announced a criminal probe into the explosion.

Bryce Reed, a paramedic who was among the first responders at the explosion site, was arrested last week for possession of pipe bomb components. He was indicted by a federal grand jury in Waco on Tuesday and pleaded not guilty to the charge on Wednesday, federal prosecutors said.

"At this time, we won't speculate on whether there is a connection between (Reed) and the fertilizer plant explosion," Champion said.

Reed's lawyer, Jonathan Sibley, said in a statement on Wednesday that Reed denies any involvement in the plant explosion.

"We continue to ask our community to reserve judgment until the facts and evidence are known," Sibley said.

Reuters

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksA special investigation by Andy McSmith
Arts and Entertainment
Books should be for everyone, says Els, 8. Publisher Scholastic now agrees
booksAn eight-year-old saw a pirate book was ‘for boys’ and took on the publishers
Life and Style
Mary Beard received abuse after speaking positively on 'Question Time' about immigrant workers: 'When people say ridiculous, untrue and hurtful things, then I think you should call them out'
tech
Life and Style
Most mail-order brides are thought to come from Thailand, the Philippines and Romania
life
News
i100
Life and Style
tech
Voices
Margaret Thatcher, with her director of publicity Sir Gordon Reece, who helped her and the Tory Party to victory in 1979
voicesThe subject is being celebrated by the V&A museum, triggering some happy memories for former PR man DJ Taylor
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Installation and Service / Security Engineer

£22000 - £40000 per annum: Recruitment Genius: This company is part of a Group...

Recruitment Genius: Service Charge Accounts Assistant

£16000 - £18000 per annum: Recruitment Genius: Are you a a young, dynamic pers...

Cancer Research UK: Corporate Partnerships Volunteer Events Coordinator – London

Voluntary: Cancer Research UK: We’re looking for someone to support our award ...

Ashdown Group: Head of IT - Hertfordshire - £90,000

£70000 - £90000 per annum + bonus + car allowance + benefits: Ashdown Group: H...

Day In a Page

General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

Chuka Umunna: A virus of racism runs through Ukip

The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
Yemen crisis: This exotic war will soon become Europe's problem

Yemen's exotic war will soon affect Europe

Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
Marginal Streets project aims to document voters in the run-up to the General Election

Marginal Streets project documents voters

Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

The real-life kingdom of Westeros

Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
How to survive a social-media mauling, by the tough women of Twitter

How to survive a Twitter mauling

Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

At dawn, the young remember the young

A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

Follow the money as never before

Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

Samuel West interview

The actor and director on austerity, unionisation, and not mentioning his famous parents
General Election 2015: Imagine if the leading political parties were fashion labels

Imagine if the leading political parties were fashion labels

Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence
Public relations as 'art'? Surely not

Confessions of a former PR man

The 'art' of public relations is being celebrated by the V&A museum, triggering some happy memories for DJ Taylor
Bill Granger recipes: Our chef succumbs to his sugar cravings with super-luxurious sweet treats

Bill Granger's luxurious sweet treats

Our chef loves to stop for 30 minutes to catch up on the day's gossip, while nibbling on something sweet
London Marathon 2015: Paula Radcliffe and the mother of all goodbyes

The mother of all goodbyes

Paula Radcliffe's farewell to the London Marathon will be a family affair
Everton vs Manchester United: Steven Naismith demands 'better' if Toffees are to upset the odds against United

Steven Naismith: 'We know we must do better'

The Everton forward explains the reasons behind club's decline this season
Arsenal vs Chelsea: Praise to Arsene Wenger for having the courage of his convictions

Michael Calvin's Last Word

Praise to Wenger for having the courage of his convictions