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.
In general the pressure against regulation comes from narrow winners (oil industry for instance) whereas the pressure for regulations generally comes from people focused on the greater good (even if they are misled by other narrow winners, for instance compliance firms).
Imagine I open a auto repair center and I perform oil changes. It would cost me money to have used oil hauled away or I could dump it down the drain. You probably support a requirement that I pay for the service.
I'm sure there are regulations that cause actual harm to small businesses that have little or no value but I wonder what percentage it would be of the total.