Workers in hazmat suits used heavy machinery one cold day in January, working to unearth some of the hundreds of drums leaking toxic waste, the snowy Front Range a backdrop to land where no one thought houses would be built when a dump was opened more than 50 years ago.

As the northern suburbs have boomed, developer Richard Dean saw opportunity in Erie. He had a plan to clean up the old Neuhauser Landfill and build 600 single-family homes to the south, banking that homeowners would be lured by the amazing mountain views. But when the Colorado Department of Public Health and Environment required him to do an environmental assessment of the 300 acres of brownfield land, his plan became messy.

It took a two-year hunt to find 84,120 gallons of chemical waste, legally buried, but lost over time.

At first, experts didn’t find any contamination in the area near the proposed subdivision at the intersection of Weld County Roads 5 and 6. They looked closer and found signs of contamination but couldn’t determine the origin. They looked even more closely and discovered more than a thousand barrels thought to have been entombed elsewhere in the landscape marked by mounds of heavy, dense clay streaked red with chemical waste.

Back in the 1960s, the waste — most of it the byproduct of magnetic tape and developer produced by IBM in Boulder — was legally dumped, burned or buried at the landfill by Sanitation Engineering, according to a 1990 assessment of the area by the Environmental Protection Agency.

But the work wasn’t executed with competence. The landfill’s permit was revoked by Weld County in 1969 because of poor operating practices.

“This used to be a deeper ravine back in the day,” said the EPA’s on-scene coordinator, Joyce Ackerman. “We believe Neuhauser just had drums dumped in the ravine, plus trash, and then just pushed dirt over the top of them. The drums weren’t very deep, (covered by) maybe a foot or two of soil.”

IBM, which could be on the hook for the cleanup as a potential responsible party, says other companies dumped their trash in the landfill without documentation. Any unmarked barrels that are recovered could belong to a separate party, the company says. Most of the waste that still has a label is from IBM, though one label has been found for Condor Chemicals and one for Texas Refinery Company, according to CDPHE records.

Geosyntec, a company hired by Dean, has been shoveling dirt under the supervision of the EPA and CDPHE since Dec. 11. As of Feb. 4, 985 drums and drum fragments had been removed, according to CDPHE. The team of 15 to 20 workers will continue to remove drums for roughly two more weeks.

The waste being unearthed consists mainly of industrial solvents. They’ve found trichloroethylene, a known carcinogen, and 2-Butanone, which has been reported as causing neuropsychological effects.

Drums still containing liquid waste will be taken to an incinerator in Kimball, Neb. Empty drums will be tossed into Front Range Landfill, just north of Neuhauser.

Dean is footing the bill for the cleanup and said the tab has reached seven figures since he bought the land in July 2015.

Since then, CDPHE and the EPA have drilled monitoring wells to collect groundwater samples, in what Curt Stovall, technical expert for the state health department, referred to as “a pretty thorough investigation” of the area where the homes would eventually be built.

The tests didn’t find any significant signs of contamination.

Dean, however, wanted to be safe rather than sorry and suggested a buffer zone between the proposed development and the landfills. The town of Erie called CDPHE, wondering if the buffer was big enough.

That led to a comprehensive review, Stovall said. “There was an indication there was methane gas.”

CDPHE then suggested Dean do a more thorough investigation to identify any potential groundwater contamination or methane migrating from the landfill.

Dean completed a phase one environmental assessment, which is used to identify potential or existing environmental contamination liabilities. A more intensive phase 2 assessment also was completed.

The results of that work came back in May 2016 and showed high amounts of contamination.

“We said, ‘that’s not coming from the existing landfills,’” Stovall said. “(The drums) weren’t buried where everyone thought they were buried.”

Aerial photos were taken as part of the phase one assessment. “It was obvious there had been some disturbance in the area south of the landfills,” Stovall said. “We were able to determine all that waste ended up south of Old Erie Landfill.

“From May of 2016 through really up to now, there have been a number of investigations out there to try to identify where the drums might be and where the highest levels of contamination are,” he said.

Workers have documented everything that they’ve unearthed during the cleanup, including labels and other fragments.

The Jan. 4 daily report by Geosyntec includes a photo of a clear plastic ring, labeled, “IBM data processing magnetic tape.” The Dec. 16 report holds a photo of a rusty barrel with a label reading, “IBM Corporation (illegible) 34th Street, Boulder, Colorado.”‘

Lawyers for IBM, a $137 billion company that still has operations in Boulder County, have been in contact with health officials and have visited the site.

“Environmental protection has been an IBM imperative for decades,” IBM spokesman Doug Shelton said in an email to The Denver Post noting that the company in 2016 was cited as an environmental leader by the CDPHE. “We are aware of EPA’s request to the property owner, and the property owner’s ongoing drum removal activities. While we are observing the work, there is not enough information to draw conclusions at this time.”

But Stovall called the argument that only one intact label has been recovered “pretty weak.”

“All their drums were picked up from the same company and delivered to the same site,” he said. “After 50 years, it’s not surprising that not many of the labels survived.”

Stovall said the good news is that the high percentage of clay in the soil kept the chemicals from migrating. Homes in the subdivisions that have sprouted up south of the Erie landfills are on city water, not wells.

“We’re still assessing the nature and extent of the contamination but we have sampled a couple of ponds and surface sediment, there doesn’t appear to be any substantial contamination at the ground surface. No exposure pathways for plants and animals,” Stovall said. “There’s a lot of plastic, glass and metal that will remain in the ground but it will have a properly designed landfill cap and then long-term groundwater monitoring.”

Dean is not concerned about the stigma that may come with living in the area. The ethereal view of the mountains will, hopefully, bring buyers, he said.

“The views to the west are incredible from here,” he said during an interview in an onsite trailer. “When it gets done, it’s going to be better than what it was before. It was always going to be open space in this area that we’re finding the barrels in now; there was never going to be homes on top of that.”