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.
Actually, moisture problems are from using things like homemade alcohol or alcohol from unknown sources, where the likelihood of it already containing a sizable percentage of water has been a problem since the Model T days.
And if that water has a bit of an aggressive pH, it can have an effect on aluminum components.
This is just not a problem with gasoline-alcohol blends from reputable suppliers unless there is serious failure in the supply chain after that, where any fuel would have been contaminated by water regardless. The fuel-grade alcohol is tested before it is added, then the finished gasoline fully analyzed afterward.
Neither moisture nor corrosion is a problem with fuel ethanol or methanol, and when you see convincing information to the contrary (like from a pro mechanic) it often originates from misguided sources, "old wives' tales" for which actual evidence existed without being well-understood. But sometimes the most professional are the ones who don't take any chances, whether "common knowledge" is factual or not, if it doesn't hurt, no big deal.
Miscellaneous polymer compounds were the real question for cars that were not originally made for modern alcohol mixtures.
Ethanol just doesn't absorb moisture into your fuel tank by itself, even from a very humid environment.
Not any more than plain hydrocarbon fuel. In old ventilated fuel tanks, extreme temperature cycling under very humid conditions draws moist air into the tank when the fuel shrinks or is consumed. Kilos of cold fuel and cold metal can continue to condense moisture from the air, when the dew point is greater than the temperature of the tank. After a while you can get grams or ounces of water rolling around in the bottom of the tank. This could build up and stall out the vehicle or keep it from starting.
If it was only an ounce or two of water at the bottom of the tank full of all hydrocarbons, it would actually help to add a gallon of plain (good) alcohol to help dissolve the separated water into the gasoline so it can pass through harmlessly like it always has since gasoline has always had trace amounts of water anyway. Condensation is about as clean as rainwater so it's nothing the engine hasn't seen.
When most mechanics see something like this it has already gotten way out of hand, and there have been waves of anti-alcohol propaganda disseminated through time which reinforce the superstitious component.
Another problem from the '80's was when you do first start using alcohol-containing gasoline in an older car, it can break up varnish that has built up in the tank for years which never would come off until some alcohol came along. This could be a few grams, end up clogging the fuel filter, and the car stalls out no different than from water in the fuel line. Direct cause-and-effect relationship undeniably due to the use of alcohol, with many independent observations. Not a water problem, but who's keeping score.
Just not any more of a problem in the 21st century, similar conditions are so rarely encountered now.