The wide flammability range, 4% to 74% in air, and the small amount of energy required for ignition necessitate special handling to prevent the inadvertent mixing of hydrogen with air.

• 在空气中氢的易燃范围很宽，从4%25到74%25，而且点燃所需的能量很少，必须特别处理，以防止无意中把氢和空气混合在一起。