The old Dow Chemical plant in Freeport, TX does this (now sold off in pieces and owned/operated by Olin and several other companies). They start from salt-water

The old Dow Chemical plant in Freeport, TX does this (now sold off in pieces and owned/operated by Olin and several other companies). They start from salt-water (for chlorine) and refined crude oil (for carbon and hydrogen), and process them through many units into a huge array of final products. Sadara in Saudi Arabia follows a similar highly integrated strategy as well. Most of East Houston (Deer Park, Bayport, Baytown, etc.) is technically lots of discrete independent refineries and chemical plants, but they have a highly integrated dense network of pipelines and tank farms through which they can each sell chemicals to their neighbors, so for many intents and purposes it's similar enough to what you're asking for, but there is an increased amount of rail transport because it can be difficult to install quite as many new pipelines through multiple other companies' land. This[0] is the unit (400 feet x 350 feet) inside the old Dow plant which combines chlorine gas and ethylene gas to make ethylene dichloride, which is later turned into vinyl chloride monomer and then polyvinyl chloride. If you zoom out, you'll notice three large chemical plants, each with many process units, stretching for about 8 miles. These three plants are all integrated with eachother in the manner you describe. As a byproduct it produces a decent amount of polychlorinated biphenyls[1] which is usually re-circulated to break it down and re-react it, but occasionally it leaks out of pumps and such and there's no "good" way to clean it up. It's a particularly carcinogenic pollutant which lasts a very, very long time in the environment. I believe burning PVC (for example, in a house fire) will also produce some amount of PCB's. 0: https://maps.app.goo.gl/q4hpLGQqmb2zcJyH6 https://maps.app.goo.gl/q4hpLGQqmb2zcJyH6 1: https://en.wikipedia.org/wiki/Polychlorinated_biphenyl https://en.wikipedia.org/wiki/Polychlorinated_biphenyl