1. More than 95% of U.S. ethylene capacity is in Texas or Louisiana.U.S. Department of Energy, report to Congress, November 2018. Quoted and checked by PolitiFact, 2019.
2. About three-quarters of U.S. ethylene capacity offline in the February 2021 freeze.S&P Global, 23 February 2021.
3. How the freeze broke refining and petrochemical supply chains.Federal Reserve Bank of Dallas, Southwest Economy, 2021.
4. Force majeure notices after the 2021 freeze.Oil & Gas Journal.
5. Cost of unplanned downtime at one site.Industrial Info Resources, 2014.

Every figure in the model sections comes from the running PetroGrid engine. The network is a typical one, not a real company's.