Block on Trump's Asylum Ban Upheld by Supreme Court
El Dorado Chemical Company (EDCC) makes chemicals. Flat Creek, Haynes Creek, and two unnamed tributaries (UTA and UTB) don't make anything, but they're waterways in Arkansas with little fishies in them. The EPA protects the fishies. As part of its operations, EDCC discharges minerals into the water.
This is OK -- a little bit. Arkansas enforces water standards through a program called the National Pollutant Discharge Elimination System (NPDES). A company can't discharge things into the water without a permit from NPDES, which includes limitations on amount and type of discharge; the EPA must approve these permits.
I Don't Like Your Fishies
EDCC thought that the limitations in its NPDES permit were too restrictive, so it applied to the state for a revision in its permit, which increased the limits on minerals in the water and removed the four waterways from the domestic water supply. Arkansas agreed, and the EPA said okey-dokey-sure -- but only to removing the waterways from the water supply.
The EPA left the mineral limits unchanged, concerned about the effects of more minerals in the water on the fishies. EDCC then petitioned Arkansas to revise the water quality standards for those waterways to increase the allowable concentration of minerals. Once again, Arkansas said yes, but the EPA said no. Then -- guess what? -- EDCC challenged the EPA's decision in court.
States' Rights at Issue
EDCC took a federalism approach in arguing that the EPA's actions should be judged under "compelling evidence" instead of "arbitrary and capricious" because the latter standard "undermines the primacy of the states." EDCC also claimed that the EPA "usurped Arkansas' role in setting water quality standards" because the implementing regulations don't refer to downstream waters, meaning EPA can't regulate downstream effects.
The Eighth Circuit disagreed with both of these arguments. Reading EDCC's single cherry-picked regulation together with other environmental regulations and the Clean Water Act, it's clear that the EPA has the power to take downstream effects into consideration when a change is made to the regulations upstream.
Having established that the EPA does have the authority to regulate downstream effects, the court agreed with EPA that the EDCC's studies on the effects of increased minerals in the water were flawed and the EPA was entitled to disapprove them when deciding to implement new water quality rules.
A states' rights approach is a questionable tactic, given the Supreme Court's recent history of upholding EPA regulatory authority in spite of the Court's more conservative bent. Then again, it may have been EDCC's only argument, as it's pretty clear the EPA didn't believe EDCC's studies showing that more minerals didn't increase toxicity in the water. In the face of such a high level of agency deference, challenging the whole regulatory scheme is the best you can do (next to not challenging the regulations at all).