ADAMS COUNTY, Colo. -- A family discovered there are cancer-causing chemicals in their well water, yet they continue to fight state regulators who say nearby oil and gas activity is not to blame -- including the abandoned oil well on the family's property.
An independent hydrogeologist, who agreed to review the family's decade-old case pro bono, believes regulators at the Colorado Oil and Gas Conservation Commission (COGCC) jumped to conclusions too quickly.
The Ohlson family bought their acreage a few miles north of Denver International Airport in roughly 2004 and built a new home. Several years afterward, they learned of the abandoned oil well from the 1970s somewhere on their property.
Though maps indicate the well is beneath their horse round pen, neither they nor excavators have been able to locate it.
The discovery soured what they consider their "dream home."
Gary Ohlson said no one told him about the oil well beforehand.
"It was never disclosed in any records or any closing documents," he said in an interview with Denver7 Investigates.
In more-recent years, a trench-like sinkhole formed in the area where the oil well is thought to be.
"Even today, the state knows that there's an abandoned oil well on our land, but they have been unable to find it," Ohlson said.
In the process of regulators trying to locate the well in 2014 and 2015, they tested the family's well water numerous times and discovered increasing amounts of benzene that exceeded legal limits in Colorado.
Benzene is a chemical found in crude oil, gasoline, and other liquids of a similar origin.
Still, the commission concluded in a letter to the family that "there is no evidence that the occurrence of benzene in your water well is due to oil & gas activity in your area or on your property." In fact, the commission suggested that the Ohlson's long-ago water well driller may have caused the contamination or the Ohlsons may have contaminated the water themselves.
"So, we've been accused of polluting our own water supply for no financial gain," Ohlson said, in part. "We have no reason to pollute the water we depend on to drink and to feed all of our animals."
Gary Ohlson contacted the Denver7 Investigates team in the wake of the state's long-running investigation and in the weeks after an oil and gas-related explosion destroyed a home in Firestone, Colo., killing two people.
The family points out what's easily discoverable on the oil and gas commission's mapping site -- that there are numerous oil and gas wells around their property, a number of which were in production in the 1970s as well.
The independent hydrogeologist acknowledged the same fact and petitioned the oil and gas commission last week -- concluding that "past investigations by COGCC have been too limited and therefore unsuccessful" in ruling out oil and gas activity.
VIEW: Hydrogeologist's letter to COGCC
Furthermore, the hydrogeologist said oil and gas wells in the early 1970s had "unlined" pits next to them to collect drilling fluids and other chemicals, which would have had the opportunity to "percolate downward into the shallow water-bearing zone beneath the [Ohlson's] property."
The hydrogeologist also said the commission should have done more extensive soil testing and that there is "no evidence that these investigations ever happened."
"Basically, they've told us unless you can prove it's our fault, we're not taking responsibility," Ohlson said of COGCC.
Since COGCC took the helm in the work it did, the owner of the abandoned oil well -- BP -- absolved itself from drawing its own conclusions on the matter.
In an email to Denver7 Investigates, a spokesperson said, in part, "We respect the judgment of the COGCC and we will continue to work closely and cooperatively with them going forward."
In separate emails exchanged by a COGCC environmental specialist and a BP strategy manager over the past few years, obtained by Denver7 through a public records request, the strategy manager said, in part, that they wanted "to see if we can find a GC signature for the benzene that would point us away from oil and gas." The COGCC specialist responded by saying, "We will be glad to assist you in any way."
Neither those emails, nor COGCC's efforts, have settled well with the Ohlson family.
"We understand we need oil in this country, but let's do it where the environment's protected and the landowners," Ohlson said.
Their frustrations ring especially true given that the commission told Denver7 Investigates that it "does not have plans to take further action" because it could never pinpoint "any potential sources of hydrocarbon contamination."
Through a spokesperson, the commission added, "If a near surface source of hydrocarbons related to oil & gas had been identified, then additional assessment to determine vertical & lateral extent would have been appropriate."
On Tuesday, the Ohlsons' hydrogeologist argued that COGCC is once again not doing the thorough analysis that science would necessitate all these years later.
All told, COGCC said even if it had determined that oil and gas was a contributing factor in the contamination, it would have recommended that the Ohlson family install a water treatment system, which the family already had done long before the contamination came to light. As such, the commission says the water tested in the family's home is free of benzene. However, the well water the family uses to irrigate their land and feed their farm animals is untreated -- and may still contain benzene among other cancer-causing chemicals.
The Ohlsons also say they would now be required to disclose the benzene in the water should they choose to sell their home.
"We have proof, in writing, that when you trust oil and gas to step up to do the right thing, they won't," Ohlson said.
