Carbon and hydrogen. CH4 - I believe it's true that most hydrogen today comes out of natural gas deposits [1]. Also helium for that matter [2]. [1]: https://ww

Carbon and hydrogen. CH4 - I believe it's true that most hydrogen today comes out of natural gas deposits [1]. Also helium for that matter [2]. [1]: https://www.energy.gov/eere/fuelcells/hydrogen-production-natural-gas-reforming https://www.energy.gov/eere/fuelcells/hydrogen-production-na... [2]: https://geology.com/articles/helium/ https://geology.com/articles/helium/