Every regulation on everything will be easier to challenge, from pesticides to smog. But your question does raise an interesting question in that we don't know how far this will go.

I really don't know what the statutes on pesticides says, so let's make one up for example purposes. Suppose a statute says the EPA can ban "dangerous pesticides." Further presume the statute provides no specific guidance on what the standards are for a dangerous pesticide.

The EPA after study determines a particular pesticide, let's call it "megabugacide" is dangerous. The EPA properly promulgates a regulation banning megabugacide. The manufacturer challenges the regulation, suing claiming that megabugcide is not dangerous as the word in the statute means.

The Loper Bright decision makes clear that the court now decides questions of law. But is this a question of law or fact? The Supreme Court suggests deference can still be shown to agency determinations of fact. Is whether megabugacide is "dangerous" a question of law or fact?

It's kind of mixes law and fact and it remains to be seen how such matters will play out under the new regime established yesterday.