DES MOINES, Iowa – After decades of talk, the ethanol industry is building multimillion dollar refineries in several states that will use corn plant residue, wood scraps and even garbage to produce the fuel additive.

The breakthrough comes at a key time for the industry, after the drought heightened criticism about the vast amount of corn used to brew up ethanol rather than be transformed into animal feed or other foods. The corn crop already was smaller than expected because of drought last year, and livestock groups were especially critical of how 40 percent of the crop being diverted toward ethanol caused corn prices to soar.

The new cellulosic ethanol technology could quiet that criticism while also making use of material largely seen as worthless.