Mazut and synthetic fuel leave different environmental hazards

How does mazut's toxicity compare with the synthetic fuel oil in Second World War wrecks?

Both are environmentally dangerous: mazut can persist and coat wildlife, while synthetic fuel may break down faster but poison through the food chain.

Neither fuel is benign. Heavy mazut persists and can physically smother wildlife. Synthetic fuel may break down more quickly, but can enter the food chain and poison organisms from within. The distinction lies in the different ways each spilled fuel can cause long-term harm.