Chemical explosion at a plant in Belle, WV

Via the New York Times, an explosion on Tuesday: 

A large explosion at a West Virginia chemical plant killed one person and injured at least two others late Tuesday night, throwing debris more than a mile away and forcing a nearby highway and some schools to close, officials said.

There were three chemical operators in the building at the time of the explosion, according to Optima Belle, the chemical company that owns the plant. Two operators were evaluated at a hospital and released, but the third operator died, the company said in a statement Wednesday.

Separately, a county official had said that four people had been hospitalized. Officials told residents within a two-mile radius of the blast in the town of Belle, about 15 miles southeast of Charleston, to shelter in place. Classes at more than a dozen schools were canceled on Wednesday as a precaution.

The authorities were investigating the cause of the explosion, which apparently involved dry chlorine and methanol, Kent Carper, the Kanawha County Commission president, said early on Wednesday. Firefighters worked to stabilize the blast, which settled into a controlled flare through the night, he said...

...The explosion occurred at about 10 p.m. in a manufacturing area owned by Optima Chemical, which operates in a complex in Belle owned by the Chemours Company, Optima Belle said in its statement.

“Preliminary information indicates that a 1,200-gallon metal dryer became over pressurized during a chemical product drying operation,” it said. “The material in the dryer was a compound used for sanitization.”

I'd like to understand what happened here. It makes sense that methanol would be flammable, but it doesn't make sense that it would be in a dryer? (maybe it was product wet with methanol?) 

Best wishes to the families and coworkers of those killed and injured.