Ethylene production activities include 'ethylene, coal-based methanol-to-olefin, industrial grade', 'ethylene, naphtha-based, industrial grade', 'ethylene, bio-based ethanol-to-olefin, industrial grade', 'ethylene, natural gas-based ethane cracking, industrial grade', and 'ethylene, naphtha steam cracking process'. Additionally, ethylene is a by-product of the production processes '1,3-butadiene, one-step method' and '1,3-butadiene, two-step method'; the production activity for this product represents a weighted average of these processes.