Combustion is a process of exothermic reaction between a fuel (a general for combustible material term) and an oxidant (substance that initiate combustion) with the production of heat and apparently producing new substances. Oil on the other hand is a general term describing which is non-polar in nature of long chain carbon molecules. Since there are different types of oils that are used in the lab and are possible for chemical spill, the general equation for combustion of oils can be written as:
OIL (fuel) + Oxygen (oxidant) -> Carbon dioxide + Water
If we have octane for example, we can write the equation as:
`2C_8H_18 + 25O_2 --> 16CO_2 + 18H_2O`
Combustion of gases which are written in books is always assumed to be combusted completely. However, that doesn't happen in reality. Incomplete combustion of gases may happen and Carbon Monoxide (CO) can be produced instead of Carbon dioxide.