Green steel advocates said relining a blast furnace is a major financial investment for steelmakers.

The Trump administration will let two chemical plants in Indiana bypass recent air pollution rules for two years. One of those plants tops the list for biggest polluters in the state — the other puts out barely any pollution, but what it does release is a lot more toxic.

Companies had until last week to explain why technology to comply with the Biden-era rules isn't available and how complying would threaten national security.