Most people are familiar with gasoline, so they rarely question its safety. However, people who are unaccustomed to alternative fuels may have misconceptions or doubts about their safety in vehicle applications. Some safety issues associated with the use of alternative fuels are outlined here.
Biodiesel is biodegradable, meaning it dissipates quickly after a spill. It has a high flashpoint and low volatility, so it does not ignite as easily as conventional diesel, increasing the margin of safety in its handling. Biodiesel degrades four times faster than conventional diesel and is not particularly soluble in water. It is nontoxic, so it is safe to handle, transport, and store. As with all alternative fuels, adequate training is recommended to operate and maintain biodiesel vehicles. (Source: EPA Biodiesel Fact Sheet, 6698.)
Compressed Natural Gas (CNG)
The fuel is odorless, and odorants must be added to ensure users can detect leaks and spills. In the event of a leak, the gas will rise to the ceiling and create a potential risk in enclosed areas. Sturdy, heavy storage tanks must be used to avoid possible hazards from the high-pressure storage.
Electrical circuits are self-contained and grounded to prevent the risk of shock from the vehicle frame. Electric vehicle battery packs store enough energy to produce a dangerous, even lethal shock. Electrolytes in the batteries may cause chemical burns, so protective gear must be worn when handling the batteries.
If used in an E85-compatible vehicle, E85 is as safe as gasoline.
Liquefied Natural Gas (LNG)
The fuel is cooled cryogenically to -260F. At this temperature, bodily contact with the liquid fuel, cold metals, or cold gas can cause cryogenic burns (frostbite). Methane gas detectors must be installed to detect leaks because odorants cannot be added to LNG.
Liquefied Petroleum Gas (LPG)
Strong tank construction is required, but the pressure hazard is less than with CNG. LPG should be odorized, and detectors are recommended to help detect leaks or spills. The fuel is extremely volatile, and LPG fires burn twice as hot as gasoline fires.
Methanol is corrosive to several metals, rubberized components, gaskets, and seals. Low flame luminosity makes M85 fires difficult to detect in the daylight. Unhealthy exposure can occur through fume inhalation, ingestion, or direct contact with skin.