| ignite vapor | 0.92 | The board said a spark of unknown origin in the tank apparently ignited the vapors. | ||
| emit vapor | 0.39 | The dormant volcano emits sulfuric vapors. | ||
| inhale vapor | 0.33 | The greatest hazard is inhaling the vapor. | ||
| reduce vapor | 0.26 | The safety board has focused on ways to reduce flammable vapors in the tanks. |