This website is about what is banned in California, ostensibly for environmental reasons. So pigouvian taxes would enable them to unban those practices while mitigating their harms.

If you’re worried about people evading the tax, you can make a border adjustment for imports across national borders. Note California is simply forcing things to be done elsewhere.

>>without things like tariffs

Right, and if the US congress[0] properly cared about the environment, the regulation would require both A) requirements to keep the manufacturing clean if done here, and B) tariffs for goods produced with polluting processes over there, scaled so the costs are somewhat higher if produced dirty.

They can produce cleanly here or there without extra tariffs and without losing market share because some other competitor externalizes the pollution costs.

[0] Tariffs are proper the domain of Congress, not any other branch. OFC, because of this, it isn't really an option for California, since states cannot levy tariffs externally or vs other states.