air freshenerGet pumped: Sierra has updated its guide to choosing the least-evil gas stations. And they’ve condensed it to fit in a handy travel-sized package: a rearview-mirror air freshener, which could not be more appropriate considering how gassy Americans are. (We consume some 400 million gallons of crudeness a day!)

Below, the top eight oil companies ranked from evil to even more evil:

Top of the Barrel

  • BP
  • Sunoco

Middle of the Barrel

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  • Royal Dutch Shell
  • Chevron
  • Valero Energy Corporation
  • Citgo

Bottom of the Barrel

  • ExxonMobil
  • ConocoPhillips