The explosion Thursday in an industrial park in Ciudad Juarez brought down the roof and a wall of the factory and sparked fires, the Los Angeles Times reported.
Fernando Mota, Chihuahua state's civil protection director, said no one was trapped inside -- contrary to reports of 40 people being trapped -- and eight people were in critical condition.
He did not indicate in interviews with Mexican media whether officials expected the death toll to rise.
Mota said the factory did not have a history of industrial problems.
There were conflicting reports on what caused the blast and fires, the Times said. Some reports blamed a boiler explosion while others indicated it was sparked by a collection of fumes.
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