Steel explains almost c10% of global CO2. Hence 2021 has seen the world’s first ‘green steel’ made using green hydrogen. Yet inflation worries us. At $7.5/kg H2, green steel would cost 2x conventional steel. In turn, doubling the global steel price would re-inflate green H2 costs by $0.5/kg. This note explores inflationary feedback loops and other options for steel-makers.