Forbidden items include high-pressure gas (lighter gas, gas cannisters for portable stoves, scuba tanks, fire extinguishers, and spray cans), flammable liquids (lighter fluid or oil, and paint), poisons (insecticide, agricultural chemicals), acidic substances (small oxygen generators, bleach), radioactive substances, corrosive substances (fluid batteries, mercury), combustible materials (matches, charcoal), gunpowder, and any other dangerous or toxic items (magnets, motors).