| unburned fuel | 0.59 | Those engines use a small amount of unburned fuel as lubricant and then expel it into the water. | ||
| unburned hydrocarbon | 0.26 | Unburned hydrocarbons are a source of air pollution. |
| unburned fuel | 0.59 | Those engines use a small amount of unburned fuel as lubricant and then expel it into the water. | ||
| unburned hydrocarbon | 0.26 | Unburned hydrocarbons are a source of air pollution. |