Navajo Nation has a sacred connection with its land. The group believes Mother Earth is a relative, an ancestor. So what happens when the land is making them sick? Some say much of the problem can be traced back to a mining incident that sent tons of radioactive waste flowing through their community. ABC's Maria Villarreal has more on the decades long cleanup and the fears of more mining in the future.

This is it.

Square I was born. We don't want to leave because this is where we grew up. The mind, they started coming in when maybe I was in 5th, 6th grade. They were all over the place. I was scared of them.

This land is home to 300,000 Navajo citizens, including retired healthcare worker Bertha Ned. Her backyard is part of an open secret that's plagued this community for more than 70 years.

My grandparents used to have a lot of sheep and goats where we all grew up. We wanted to stay here.

Hundreds of abandoned uranium mines line the 25,000 sq mi of the Navajo Nation. And now a possible renewed threat, striking fear among its citizens. During the Cold War era. The US. Department of Defense contracted with several companies to extract almost 30 million tons of uranium from Navajo lands for American nuclear programs.

There's my, my dad participating in the ceremonial parade. And this one here, there's my older sister again, April, with my mom. I was probably four months old in her tummy. Get up here. Come here.

Larry King was an eyewitness to the largest radioactive spill in American history, which occurred on Navajo lands in 1979.

That's about where the location of the tylene's ponds are. And all that contamination flowed on the other side of the hilltop here.

The Church Rock spill occurred when an earthen dam holding back 94 million gallons of radioactive waste failed, pouring its toxic waste into the Puerca watershed that lines Larry's property. 44 years later, the cleanup is still underway.

Their method of cleanup was hire some labors, give them a shovel, five gallon buckets, start scooping all that slime that was left behind into those buckets.

Two decades later, Navajo researchers released the DNA Project, a study that found people living near abandoned uranium mines had significantly higher risk for respiratory illnesses, cancer and kidney failure. Shortly after, the Navajo Nation passed a ban on uranium mining, saying as long as there are no answers to cancer, we shouldn't have uranium mining on the Navajo Nation.

We want our future kids, grandkids, all to be safe. That's what we want. Because we lost a lot of people that were getting uranium mine. They had problems, respiratory problems, cancer and all kinds of stuff. We rather have a safe place to live and people to be safe.

Near the mining site, the Red Water pond was once home to as many as 30 families, but now there's only a handful. Bertha Nez's family has moved at least three times since 2007. Under the EPA's temporary housing program during cleanup efforts.

We don't want to leave because we're used to this our residence, and this is where we grew up.

They say the environmental contamination has bled into every aspect of their family's life, haunting them to this day.

We don't have the sheep anymore. At one time, we had a sheep we butchered, and it wasn't good anymore. We opened it up inside. It was all yellow. We couldn't take it anymore. Damage has been done already. People are sick for cancer and respiratory problem, and they pass away, most of them.

In the last decade, corporate and government settlements started funding cleanup efforts to reduce risks to the Navajo people. Community fears are growing with the possibility of new threats as renewed uranium exploration progresses along Navajo borders.

So this is New Mexico.

Boo Nigrin is the president of the Navajo Nation. And so this is what we're talking about when we say the checkerboard situation, where there's parts of here that don't.

Belong to the nation.

So you'll see little squares there that say, that's checkerboard. So that's not part of the Navajo Nation. Some are private land, state land, and so they're all within the boundaries of the Navajo Nation, but they're not Navajo Nation lands.

The private land he's talking about is now owned by Toronto based corporation Laramide, a company hoping to extract uranium from the Earth through a modern day technique called insitu recovery. ISR for short. According to the Nuclear Regulatory Commission, ISR is a primary extraction method currently used to obtain uranium from underground. In an email to ABC News, laramide said, ISR is more akin to a water treatment plant than what most people would think of as mining. But whether it's a traditional form of mining or a water based technique, the desired end result is the same uranium.

People are always going to try to find a loophole, but to me, we hope that officials understand that they shouldn't be doing that in the first place.

The Navajo government has battled over the jurisdiction of this property since it's surrounded by the nation. But the courts have ruled the operations are on private land and not subject to Navajo sovereignty.

We truly believe the Navajo Nation did their part supplied uranium. We still have over 500 plus mines that are still abandoned and not cleaned up. I know it's going to cost a lot of money in the billions of dollars, but we got to start somewhere.

In August, the Department of Energy awarded Laramide a nearly $2 million grant to study how to restore the groundwater source they plan to use.

If they move forward, it's subsidizing with US. Taxpayer money, foreign companies to try to get uranium out of the ground, in this case, in places where the local communities and the Navajo Nation don't want it out of the ground, they want it left there. Laramide is a mining company. Its goal is to get uranium out of the ground, sell it to utilities to make profit.

Chris Shewey says the companies that mined the Navajo Nation decades ago have a questionable track record what we've seen from.

The history of the uranium industry. Once the financial benefits were exhausted, the company's up and left.

A major concern with the proposed project for many is the potential impact on one of the region's only freshwater sources, the Westwater Canyon aquifer. Many fear this would add to an already existing water shortage. 30% of homes in the Navajo Nation do not have access to clean running water.

You need to protect the aquifer. The water water is life.

What does that mean for the 15,000.

People that live in this area?

That's a disaster for the community around this area, complete disaster.

What does justice mean in this situation?

The legacy cleanup, and also with this one NRC license that's still on the table, and the threat of new mining from that license. That license is rescinded.

The NRC says the primary restoration goal for any company is to return groundwater to pre injection levels. If that's not possible, the NRC says it will accept the standards set by the EPA under the Safe Drinking Water Act.

The NRC's own admission there has never been a mining company that has returned an aquifer back to its pre mining stage.

You run the risk of committing a portion of your groundwater to long term contamination.

The Environmental Protection Agency has been the lead agency addressing abandoned mines in the area since cleanup began in 2008. We met with the EPA's Jacob Phipps on the Luca Chukai mountains. He says there are approximately 32 abandoned uranium mines in this area.

For those people that will say you haven't been able to clean up one mine in decades, what's taking so long? How do you respond?

We hear a lot of times in these communities that the process is just taking too long. Our process does take a long time. We step foot on site is we have to determine where the contamination is, how far is it in the ground, how widespread is it? That takes some time.

Does it feel like this is an uphill battle for you and the staff and for that matter, the nation that has been trying to clean this up for so long?

We've committed to do cleanup on at least 240 of these mine sites, and I think that they're all achievable.

Navajo leaders say they are determined to keep fighting for the land that's so closely tied to their future. What does success look like here when it comes to these mines?

Success for me in my term as president would be to have one mine clean, and that would be a huge success, something that hasn't been done in 20 plus years.

Navajo leaders say they are determined to keep fighting for the land that's so closely tied to their future.

After all this time, you have continued to fight. How much more fight do you have in you?

Until the day I leave this mother Earth. What keeps me going is looking out my front door and seeing the landscape and also for my grandkids looking at them. And for that reason, I keep myself going.

Land that's worth fighting for. Our thanks to Maria.

Hi, everyone. George Stephanopoulos here. Thanks for checking out the ABC News YouTube channel. If you'd like to get more videos, show highlights and watch live event coverage, click on the right over here to subscribe to our channel. And don't forget to download the ABC News app for breaking news alerts. Thanks for watching.