Petrol is safe enough that you can let untrained people pour it from one tank to another. Spill a little, no problem. Ammonia is a gas at standard temperature,

Petrol is safe enough that you can let untrained people pour it from one tank to another. Spill a little, no problem. Ammonia is a gas at standard temperature, and will be transported and used as a liquid under pressure. If you expose liquid ammonia to the atmosphere, all of it boils off rapidly. The IDLH (immediate danger to life and health) limit for ammonia is 300 parts per million. If you release 15 grams of ammonia inside a typical garage, you have exceeded the IDLH threshold. If you spill just 1 gram, the smell is so strong the average person is running away in fear.