Unleaded gas is safer of course. Leaded fuel was used to lubricate the seat and face of the intake and exhaust valves. Not for octane. Without lead, the valves would burn up and you would need a valve job. And using unleaded help the environment cause leaded id poisonous
Head to head diesel wins cause it has a lot more power behind it . For example diesel has 14,000 btu of power as gas only has 125,000 btu of power. Some places diesel will be found a lot more than gas but most places they're the same . Diesel is also better for the economy
Carbon monoxide reduces the flow of oxygen in the bloodstream and is particularly bad for people with heart diesese. Hydrocarbons are very toxic and a potential cause of cancer
Vehicles contain many different fluids, including motor oil, antifreeze, gasoline, air-conditioning refrigerants, and brake, transmission, hydraulic and windshield-wiper fluids. In most cases, these fluids are toxic to humans and animals, and can pollute waterways if they leak from a vehicle or are disposed of incorrectly. Many vehicle fluids are exposed to heat and oxygen while an engine is running, and undergo chemical changes. These fluids also pick up heavy metals from engine wear and tear, making them even more toxic to the environment.