What is coal ash and how is it regulated?

CATHY WURZER: Crews right now are digging up soil and pumps are pulling water to clean up a leak of sludgy water at a power plant near Cohasset in Northern Minnesota. Two weeks ago today, Minnesota Power reported that wastewater containing coal ash had spilled from a pipeline at the Boswell Energy Center. Coal ash is pretty much what it sounds like, the waste product created when we burn coal for power. The company and the State Pollution Control Agency say about 5.5 million gallons of water containing ash leaked, with some of it reaching Blackwater Lake on the Mississippi River.

As of yesterday morning, the MPCA says about 639,000 gallons had been pumped back into the plant's system, and sampling from the area has found higher-than-normal levels of sulfate and boron. All of this comes as the federal government is getting stricter this year with how coal ash and coal ash wastewater are regulated.

As an energy reporter and investigative journalism professor, Kari Lydersen has learned a lot about coal ash. She's on the line to help give us some context. Thank you for joining us.

KARI LYDERSEN: Hi, thank you.

CATHY WURZER: I understand back in 2022, you led a student investigation of coal ash pollution around the country. Explain that project for us, if you could, please.

KARI LYDERSEN: Yeah, with the investigative lab that I lead at Northwestern University and the Graduate Journalism School, and then with Energy News Network where I work, and also Detroit Public TV'S Great Lakes Now, we had this team of students who were investigating, basically under the 2015 coal ash rules, companies that operate coal power plants have to do groundwater monitoring around their coal ash dumps and post that data online. But it's very rarely looked at seemingly by anyone.

So we were looking at a lot of this groundwater monitoring data that was posted online by the companies, and then just the larger issues with coal ash nationwide, and it turned out to be at a really good time because in early 2022, this was when the Biden administration EPA actually did start essentially enforcing these rules that had been on the books for seven years, but not really enforced until at that point. So we looked at all different environmental justice and drinking water and other implications of this coal ash pollution.

CATHY WURZER: I don't think people really understand much about coal ash, to be honest with you. What are the human and the environmental concerns associated with coal ash?

KARI LYDERSEN: Yeah, it's really this huge issue that, especially until recently, and even now, has just surprisingly not gotten much attention given what a massive volume of contamination it is and really what a big threat it is in the US. The Kingston spill in Tennessee in 2008 got a lot of attention, but that is really just the tip of the iceberg of ongoing problems and potential disasters that could be looming.

So when coal is burned to produce electricity, this toxic coal ash results, and there's been about 5 billion tons of coal ash produced over the last 100 years. And it doesn't disappear, that's all still with us.

And a large-- most of that is stored in different types of impoundments and landfills and just dumps, and even just scattered over land where, in almost all cases, the actual data from the companies themselves show that it is contaminating groundwater and, in some cases, also surface water. So there's public health risks. There's serious environmental risks. And since we're still burning coal, it's just a problem that continues to keep growing.

CATHY WURZER: You mentioned the coal ash spill in Tennessee in '08, and that was a huge mess. I think that was, what, more than a billion gallons of the sludge that was over hundreds of acres after this containing wall gave way. That was a mess. What has changed since '08 of anything in terms of trying to prevent that kind of disaster from happening again?

KARI LYDERSEN: Yeah, there have been big changes, at least if you take the glass half-full kind of approach because the 2015 Federal Rules on Coal Ash were hashed out, and after a pretty long, contentious process, were implemented. So those rules do require that, for most coal ash impoundments or repositories, the companies do monitor the groundwater and post those results online.

And in theory under the rules, they're supposed to clean up contamination that results and prevent contamination from happening and come up with closure plans for the impoundments that won't result in ongoing contamination.

So the rules look pretty good, you could say, on paper, but they didn't cover and still don't cover all the coal ash repositories. There have Been updates, thanks to legal action by advocates, that have expanded the coverage of those coal ash rules.

But it's like I mentioned just in the past couple years, that the government has actually really started enforcing those rules, and there's just this massive backlog of impoundments that have been, all this time contaminating groundwater, really, with no accountability. So even with the rules, there's still just this massive enforcement challenge that continues.

CATHY WURZER: So you mentioned the impacts in terms of the contamination. And I'm wondering, especially for places like Northern Minnesota, wild rice is a very important crop that's up north. And I'm wondering, how might this kind of pollution affect aquatic plants like wild rice? Do we know?

KARI LYDERSEN: Yeah, I don't know if there's been studies on that in particular, but I know that's a really delicate crop. And this is serious, serious pollution. One, it's actually sludge, as you mentioned, that's a physical-- thick, physical material that can drown things out, and then it's full of toxic heavy metals, things that are dangerous to humans, and I'm sure also to plant life, too.

And it can bioaccumulate, probably, in plants depending how the pathways go. So it's absolutely not something that you want in any water body that's crucial to the ecosystem or to human use.

So this may sound like maybe a simplistic question, but as I'm listening to you. With all of these impoundments, with all of this coal ash across the country, can anything be done with that byproduct? Any potential beneficial use of coal ash in anything? Or can we do anything with this at all.

Yeah. Well, that's a great question. There is a whole sector of beneficial reuse, which is the exact term that's used. And it is actually used in-- certain types of coal ash are used in making drywall. It's a really crucial component in concrete. It actually replaces Portland Cement, which is very greenhouse gas-intensive. So it can potentially play a good role environmentally in concrete.

And it's also just used as fill. Like many construction projects and lake fronts are actually built up with coal ash. So some of this beneficial reuse, if it's really encapsulated in concrete and it's not exposing-- humans aren't exposed to it, like that really could be considered a beneficial reuse.

But there's also a lot of controversy about the unencapsulated uses, the uses just putting it in the ground as landfill where it still can leach contamination. And there's a number of horror stories where that has happened, including the town of Pines in Indiana where the whole town failed-- it really exhibited serious health problems linked to the coal ash, and it became a hugely expensive Superfund cleanup.

So there are these different types of beneficial-- or beneficial use out there. And then really, the kind of gold standard for dealing with it, if it's not used in concrete-- and not all types of ash can be used in concrete or those safe ways. So really, the other solution is just to get it out of water because most of the impoundments are in water, in groundwater, or in contact with groundwater. So to move it to a lined, dry, safe landfill where it can just be stored without contaminating the soil or groundwater or surface water.

CATHY WURZER: Real quick, final question here, Kari. Minnesota Power plans to stop operations at this specific power plant by 2035. We have this new state law requiring a carbon-free electricity by 2040. So I'm wondering, what might happen to all that coal ash at that plant?

KARI LYDERSEN: Yeah, that's same story all around the country. Many, many coal plants have closed and the coal ash still remains there, and the responsible company still needs to follow those rules and get it cleaned up.

But in other cases, we have seen things where private equity investors or LLCs or other entities end up taking control of the site and being even less accountable than these power companies have been, so there's always that risk. But Yeah, that coal ash is still going to be there, and someone is still obligated to make sure it's not contaminating and ultimately clean it up.

CATHY WURZER: I appreciate your time, professor. Thank you so much.

KARI LYDERSEN: Thank you.

CATHY WURZER: Kari Lydersen is a journalist and Professor who teaches investigative journalism at Northwest's Medill School of Journalism in Illinois.