EPA trumps States' regulators

Ruling out today: the EPA can override state officials and demand some anti-pollution measures that may be more costly than those allowed by the state.
from the Times:

The 5-4 decision, a victory for environmentalists, found the EPA did not go too far when it overruled a decision by Alaska regulators, who wanted to let the operators of a zinc and lead mine use cheaper anti-pollution technology for power generation.

The four dissentors, Rhenquist, Thomas, Scalia, and Kennedy argued that this undercuts states' authority: "After today's decision, however, a state agency can no longer represent itself as the real governing body. No matter how much time was spent in consultation and negotiations, a single federal administrator can in the end set all aside by a unilateral order," Kennedy wrote.

I haven't read through the decision yet- but on the states stuff, my gut says this: te EPA is a valid federal agency that has been granted power to promulgate regulations and enforce environmnetal protections throughout the country. If state authorities conflict with EPA regulations, what power does the EPA have? It is not as if state authorities can give out radio licenses that the FCC doesn't allow. The EPA's authoritative scope is no different.
Problems exist where the government impliments federal programs or regulations where previously the area regulated was under the province of state power. I wasn't under the impression that's the case here.
Conversely, that is the case in proposals such as tort reward caps, for instance. It was also the case with New Deal legislation.
Still, that something is problematic doesn't make it automatically invalid. Just new, and thus, requiring prudence.