I also recently saw a news story on local businesses selling drug paraphernalia. It actually turned out to be a huge expose. I wish I could remember what network I saw it on...
Anyway - I understand your anger and frustration. And I also agree with the quote above - about a small group of citizens changing the world. Good for you for writing to the company.... Yes, you were being reactive, but at the same time, look at the letter you received back from Chevron. Who knows how much they will follow through on, but at least they responded.
And, just as a side note, if it was me - I'd be calling every local news station I could find. Who knows - you may be making a much bigger difference than you thought...