Half a dozen men in hard hats watched as their drill rig rose more than 100 feet high. On top, an American flag fluttered in the sun. At the work site just east of Interstate 25 in Adams County, the crew was preparing for the start of an unusual job.

Instead of drilling a mile beneath the surface to extract oil, they were about to rip a well out of the ground. In its place, they'd leave cement plugs strong enough to seal the hole for thousands of years.

The well in question is known as an "orphaned well." When oil and gas companies go bankrupt or stop taking care of their equipment, their wells fall into the state's hands. Thus, the term "orphaned."

The Colorado Oil and Gas Conservation Commission knows of 275 such wells and 422 associated locations or facilities. There are likely more.

Enter crews like the one in Adams County. At the edge of the site, Mike Hickey, an engineer with the COGCC's orphan well unit, braced himself for the day ahead.

"We never operated this well," Hickey said. "So we're not completely sure what's in it until we start pulling it out."

In front of him, the rig fired up.

Graphic by Rae Ellen Bichell/KUNC

A growing threat

Some orphaned wells are more than 100 years old, others only two or three decades.

Many lack important records and documentation. At least 88 are considered "high-priority" for plugging, meaning the state sees them as a potential threat to nearby homes and buildings.

That's why, in one of his last actions as governor, John Hickenlooper set a deadline to plug most of the wells by 2023. He made the announcement in July 2018.

The executive order also included a tenfold increase in state funding to fast-track the cleanup.

Now, a year after the deadline was set, the COGCC has assembled a brand new staff, including several engineers and environmental specialists dedicated solely to solving the orphan well issue.

Dave Andrews, manager of the COGCC's orphan well unit, said the state has plugged 10 mid-to-high priority wells since last July. Now that it's fully staffed, Andrews said the unit's goal is to plug at least 38 per year.

"I don't think we're in a position where (the deadline) is going to be easily obtainable," he said. "We're definitely going to be pushing hard to get to that point."

Plugging just one of the 275 wells on the state's list can take more than a week - not counting the months of paperwork leading up to the actual job. By the time it's over, it can cost upwards of $80,000.

KUNC's Matt Bloom spent three days with a crew to learn more about the process.

Credit Matt Bloom / KUNC / KUNC Dusty Daniels (right) talks to one of his crew members. Daniels and his crew drove four hours from Rangely, a small town on the Western Slope, to do the orphaned well job. The orphaned well is pictured center right.

Day 1

I pulled up to the well site on a Thursday morning, just as workers were getting started for the day. As we walked towards the well, I asked Mike Hickey how it got orphaned in the first place.

"It was kind of a sad story," he said. "The sole proprietor got really sick."

Because of that, Hickey said the family-run, Canadian company basically stopped taking care of it. Soon after, the violations racked up.

"And so in the final hearing (the state) said, you know, your license to operate in the state is revoked," Hickey said. "And as soon as that happens, it becomes an orphan, doesn't have an operator anymore."

That was three years ago. Since then, the COGCC has taken control and classified it as a high priority for plugging. Hickey said that was because of its proximity to new neighborhoods in nearby Brighton.

"This is one of the first times that I've been out here when you couldn't hear roofing hammers going on on all sides," he said.

On the surface, the well looked small, a couple feet of dirty pipe jutting out of the ground with rusted valves and meters. But it's about a mile deep underground.

Credit Matt Bloom / KUNC / KUNC The crew uses a massive drill rig to yank rods and casing from an abandoned orphan well in unincorporated Adams County.

The crew started by removing the inner workings of the well, what're called rods. They used a drill rig to yank the long, thin pieces out one by one.

But then, something made the crew stop. Hickey ran over to see what was wrong. After a minute, he waved me over.

"You can see all the goo on these and it's getting worse," he said, pointing to a black material dripping off some of the rods. "The crew can't drive down the highway with this. It's not allowed. It's too messy."

The substance was paraffin, a greasy material that gloms onto the inside of wells after years of neglect. The crew now needed to call in a special truck called a hot oiler to clean it.

We waited an hour, but no luck.

"Looks like we may be shut down 'til morning," Hickey said.

Credit Matt Bloom / KUNC / KUNC Mike Hickey, an engineer with the Colorado Oil and Gas Conservation Commission, makes a phone call. Hickey is one of the recent additions to the state's ramped up orphan well unit.

Day 2

So, I came back the next morning. By the time I arrived, the rods were all cleaned up.

The crew got a hot oiler to come by first thing to pump water down the well. Now, they're back at it, removing the inner pieces of the well one by one.

"There's a lot of stuff that goes into it," Hickey said. "There's the rods and then there's the tubing and then there's the casing."

This will likely take the entire day, Hickey said. In the meantime, he showed me the plug.

Credit Matt Bloom / KUNC / KUNC Mike Hickey points to the plug. The toothed mechanism is lowered into the well more than a mile below the surface. A controlled explosion expands the plug, sealing the well shut.

The plug is attached to the end of a long metal pipe, which is packed with explosives.

Once the well is cleared of its inner rods and casing, the crew lowers the plug underground, detonates it and seals the cracks with cement. They'll repeat the process four more times at various depths.

As the six-man crew took a break, I learned that they were from Rangely, a small town on the Western Slope. The state contracts them to do several wells at a time.

Dusty Daniels is their manager. He brings his Irish Terrier, Chip Daniels, along to every site.

"My wife bought him eight years ago because she needed a companion," Daniels said. "She couldn't take him one day so I brought him to the rig with me and he's been here every day since."

Combined, they've plugged about two dozen orphaned wells in the past three or four years. And he hopes they can do more.

"This is actually in my opinion some of the better work especially for the state," Daniels said. "It's clean cut, laid out. 90% of the time it goes like it's supposed to."

For the most part, the rest of the day went smoothly. The temperature hit 101 degrees though, which slowed things down. But Mike Hickey's crew didn't stop.

"Peyton Manning made the NFL look easy," he said. "So these guys are really good at what they do."

And unlike me, they worked right through the weekend.

Credit Matt Bloom / KUNC / KUNC A crew member hangs from the drill rig to help steady a piece of the orphaned well being pulled from the ground.

Day 3

I didn't check back in until Monday.

On his phone, Hickey showed me a photo of the rig at sunrise.

"Snapped a picture of the rig this morning because there were hot air balloons in the background," he said.

Hickey said they detonated the first plug early Saturday. That one was a mile down. Then they set another at 2,500 feet.

Now, they were putting a third plug in at 1,500 feet, just below an aquifer to protect the water. It might seem excessive, but Hickey said there's a reason.

"Most people are thinking in the 20-year timeframe. But we think 1,000-year plugs, really, 10,000-year plugs. These have to be permanent," he said.

I asked him if he thinks there will ever be a day when the state doesn't need to clean up after oil and gas operators. He said he was optimistic.

"Most of the well plugging that goes on in this state is operators plugging their own wells," he said. "These (orphan wells) are by far a minority compared to the guys who are doing it right."

After the aquifer protection plug is set, there were just a few more steps.

"And then we cut it off four feet down, weld a cap on it, put identifying information on that cap, bury it, and sweep the floor," he said.

Before and after photos courtesy of Mike Hickey.