1998 Buick LeSabre Owner's Manual - Page 256

IA CAUTION: I Gasoline vaporis highly flammable. It burns violently, and that can cause very bad injuries. Don't smokeif you're near gasoline or refueling your vehicle. Keep sparks, flames and smoking materials away from gasoline. To remove the cap, turn it slowly to the left (counterclockwise). The cap has a spring in it; if you let go of the cap too soon, it will spring back to the right. While refueling, hang the tethered cap from the hook on the fuel door. 6-6