By Lisa Maria Garza
WEST, Texas (Reuters) - Two weeks after 14 people were killed when a Texas fertilizer plant exploded, investigators searching through the charred rubble said they still do not know how much fertilizer was at the plant, including potentially dangerous ammonium nitrate.
Investigators said on Thursday they have not yet determined the cause of the explosion on April 17, which flattened a section of the town of West, Texas, and also injured some 200 people. They hope to have a preliminary finding on the cause by May 10, said Chris Connealy, Texas fire marshal.
During a tour and briefing on Thursday for a limited group of reporters at the site of the blast, assistant state fire marshal Kelly Kistner said West Fertilizer Co, the owner of the facility, does not have a firm number on the amount of fertilizer at the plant then.
"We know there's ammonium nitrate. Everybody in the world knows we got ammonium nitrate. Beyond that, I don't know the exact names of all the other chemicals that have been brought in," Kistner said
The plant stored and sold liquid anhydrous ammonia fertilizer to farmers in the area. It also mixed ammonium nitrate with other dry fertilizers for use in stimulating the growth of crops such as corn, wheat and milo.
Documents from the Texas Department of State Health Services show the West plant was storing 540,000 lbs (245,000 kg) of ammonium nitrate and 54,000 lbs of anhydrous ammonia in 2012. Ammonium nitrate was among the ingredients in the bomb used by Timothy McVeigh to blow up the Oklahoma City federal building in 1995, killing 168 people.
"This is planting season. This is fertilizing season. This is a busy, busy time for this facility right here. So they were constantly turning product, tons a day, out of this facility," Kistner said.
Authorities said they have interviewed more than 370 witnesses and received more than 200 leads.
Kistner said investigators have not encountered any problem with getting the owners and operators of the plant to cooperate. West Fertilizer Co is owned by Adair Grain, which in turn is owned by local farmer Donald Adair.
"The people who own the place and operated the place have been providing information as it's been requested by investigators," Kistner said.
At a separate press conference on Thursday, Frank Patterson, emergency operations coordinator for McLennan county Texas, where the plant was located, said that he had not read a report submitted by West Fertilizer Co to his office and the state last year with an inventory of chemicals including types and amounts.
"With the amount of reports that come into our office, I do not read every one of them," Patterson said. "They are forwarded to local first responders."
Eleven firefighters and paramedics were killed in the explosion that erupted about 20 minutes after they responded to a fire at the plant. One question raised is whether they were aware of and had been trained on how to respond to a fire with dangerous chemicals.
(Writing by Greg McCune; Editing by Lisa Shumaker)