So you would not expect proponents of clean energy to embrace — and even subsidize — paper mill operations under the banner of fighting climate change.

You would be wrong.

And that’s insane — because black liquor is nasty stuff. Burning it produces sulfur oxides, nitrogen oxides, particulate matter, arsenic and lead, and as much carbon pollution as coal.

Those pollutants are part of the reason that paper manufacturing giant WestRock remains the single largest privately owned emitter of toxic air pollution in Virginia, according to EPA data. WestRock owns three paper mills in Virginia that produce black liquor renewable energy credits for the Maryland market, as well as paper products for the rest of the world. Its mill in Covington, Va., was the No. 1 emitter of toxic air pollutants in Virginia in 2015, besting even the state’s largest coal plants.

Data from the Maryland Public Service Commission suggest renewable energy credit payments from Maryland consumers to WestRock in 2016 totaled more than $7 million. That’s not a lot of money for a multinational corporation with nearly $5 billion in assets. But 7 million bucks would be enough to put solar on the homes of hundreds of low-income Maryland residents. Repeated year after year, that’s a lot of solar energy forgone.

WestRock is not the only Virginia beneficiary of the black liquor gravy train. International Paper’s Franklin Mill facility earned an estimated $1.3 million in renewable energy credit payments from Maryland in 2017. It also earned the No. 3 spot on the list of top toxic air polluters in Virginia.

I have nothing against paper; lord knows I’m responsible for a lot of cardboard boxes showing up at my house. And I understand why a company would burn waste products for power rather than disposing of them and paying for electricity. Paper companies have done it since the 1930s; it saves them money.

But I cannot fathom why Maryland’s electricity consumers should pay extra to multinational corporations — in other states! — for a practice that makes air pollution worse, and one that does not even put electricity on the grid as part of a program that is supposed to procure clean energy and lower carbon emissions in Maryland.

Black liquor owes its place in the Maryland renewable portfolio standard to a single paper mill in western Maryland that benefits from renewable energy credits sales, though in much lower amounts. Luke Mill generated about $780,000 worth of renewable energy credits in 2017, according to the Maryland PSC report.

When Maryland environmentalists tried to remove black liquor from the renewable portfolio standard for the obvious reasons, the argument against doing so was simply that Luke Mill needed the money. So today, even as Maryland moves toward passage of a bill that would increase the renewable portfolio standard to 50 percent by 2030, black liquor remains firmly a part of the picture.

There is an extra layer of irony here. While 94 percent of black liquor renewable energy credits come from outside Maryland, the renewable portfolio standard does not allow out-of-state solar facilities to sell renewable energy credits to Maryland.

Yes, that’s right: Maryland wants to subsidize Virginia’s toxic air polluters, but it draws the line at actual clean-energy producers.

Perhaps it is not the place of a Virginian to point fingers. Our own renewable portfolio standard, while merely voluntary and modest to a fault, still manages to suck money from Virginia ratepayers for millions of renewable energy credits from the burning of trees and trash.

But all this proves is that we Virginians are plenty capable of messing up our environment on our own in the name of clean energy. We don’t need Maryland’s help with it.