"And I hadn't even told him the truth. Actually, the shit coming out of Basco's pipes was a hundred thousand times more concentrated than was legally allowed. ... That kind of thing goes on all the time. But no matter how many diplomas are tacked to your wall, give people a figure like that and they'll pass you off as a flake. You can't get most people to believe how wildly the eco-laws get broken, but if I say "More than twice the legal limit," they get comfortably outraged."

-- Neal Stephenson, Zodiac (1988) http://en.wikiquote.org/wiki/Neal_Stephenson#Zodiac_.281988....

(I'd include the previous paragraphs in the quote, to show the conversation the protagonist actually has about this, if my copy wasn't on loan to a friend right now, dammit! If anyone else can post that, that's be cool.)