by, guess who, toyota. >> we've asked people to evaluate exponent's analysis and they said it was not a very good analysis. >> reporter: exponent is an engineering firm with the nickname "masters of disaster." when a big corporation gets in trouble, these are the guys they call to help defend them. and those big corporations read like a who's who of companies with major product or pr problems over the past decades, like exxon. when the "valdez" ran aground, exponent concluded a double-hull wouldn't have prevented a spill. exponent worked with tobacco companies, arguing against the labels warning of the hazards of smoking. dr. stanton glance has been battling tobacco companies for years. he claims exponent is basically a hired gun for big business. >> if i were toyota and you wanted somebody to do this, i would have found somebody who didn't have this baggage. to get an independent assessment