Turning "environmental regulation" into a unified bloc that must be either supported or opposed in totality is a manipulative political maneuver and it should be forcefully rejected.
Regulations are not people, and they don't have rights. It is fair and reasonable to demand that environmental regulation justify its existence with hard, scientifically verifiable data or else get chopped. Clearly, banning leaded gasoline has that kind of justification, and therefore I'm strongly in favor of maintaining that ban and extending it wherever it isn't in place yet. The same reasonable standard should be applied to other regulations across the board.
I also don't agree on the principle that regulations are "harmful" or "helpful." Rather, you have to define who the regulation harms, and who it helps. For example antitrust enforcement harms shareholders and some employees of very large firms, but it helps many employees and arguably improves the landscape for competition between many smaller firms. So whether a regulation is preferable comes down to values.
In the case of leaded gas, it harms basically everybody, but it helps fuel companies, so it was an easy thing to change.
Also, your assertion that lead “helps fuel companies” is fundamentally mistaken. Gasoline is a mass-produced commodity. Oil companies have single digit profit margins. These companies aren’t making Big Tech profit margins where they can absorb higher costs without passing them along to consumers. Cost savings from things like gasoline additives accrue to consumers at the gas pump.
https://www.smithsonianmag.com/smart-news/leaded-gas-poison-...
In an age of natural rubber components, poorly sealed fuel systems with steel tanks and aluminum carburetors pretty much anything other than ethanol is the "right choice".
And once they ruled out ethanol they settled on lead because it was cheap/profitable. Obviously they chose wrong, they should've picked something more expensive but less terrible.
These weren't cartoon villains with monocles twirling their mustaches. They were normal humans making pragmatic decisions based on the constraints they faced. Without knowing the details people cannot understand what future similar fact patterns may look like.
That said, it should be no surprise to anyone that nobody wants to talk about "well we don't know how bad the harm of leaded exhaust is, we know it's not good, but it's diffuse and undefined so we'll round it to zero/negligible" type decision making, for that sort of unknown rounds to zero logic underpins in whole or part all manner of modern policy discourse.