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The Texas fertilizer plant where an explosion killed as many as 15 people late Wednesday was cited by state officials nearly a decade ago for failing to obtain or to qualify for a permit, records show.

West Fertilizer Co. was cited by the Texas Commission on Environmental Quality in 2006 after it received a complaint in June of that year of a strong ammonia smell emanating from the 1,500-square foot facility in a farming community roughly 20 miles north of Waco. Agency records indicate that the person who lodged the complaint said a lingering ammonia smell was "very bad."

The plant, which was founded in 1958 and generates an estimated $2 million in annual sales, reported to the Environmental Protection Agency and local public safety officials that it presented no risk of fire or explosion, according to documents cited by The Dallas Morning News.

The company, which employs up to 20 workers, reported having as many as 54,000 pounds of anhydrous ammonia in stock in an emergency planning report required of facilities that use toxic or hazardous chemicals. But the report, according to the newspaper, stated “no” under fire or explosive risks. The worst possible scenario, the report said, would be a 10-minute release of ammonia gas that would kill or injure no one.

The second-worst possibility projected was a leak from a broken hose used to transfer the product, which again would cause no injuries, the report indicated.

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The plan said the facility did not have any other dangerous chemicals on hand. It says that the plan was on file with the local fire department and that the company had implemented proper safety rules, the newspaper reports.

Advisories on safe handling of anhydrous ammonia typically state that the chemical is not considered an explosion risk when in the air as a gas. They add, however, that it can explode in certain concentrations inside a container.

“Emergency responders should not mix water used for firefighting directly with anhydrous ammonia as this will result in warming of the product, causing the liquid to turn into a vapor cloud,” according to the website of Calamco, a growers’ cooperative in California.

Explosive hazards with fertilizer are more commonly linked to ammonium nitrate, which is widely used in agriculture and as a mining and construction explosive. A mixture of ammonium nitrate and fuel oil was used to construct the bomb that decimated the Alfred P. Murrah Federal Building in Oklahoma City on April 19, 1995.

In 2001, an explosion at a chemical and fertilizer plant killed 31 people and injured more than 2,000 in Toulouse, France. The blast occurred in a hangar containing 300 tons of ammonium nitrate, which can be used for both fertilizer and explosives. The explosion came 10 days after the Sept. 11, 2001, terrorist attacks in the U.S., and raised fears at the time it was linked. A 2006 report blamed the blast on negligence.

The Associated Press contributed to this report.