A judge has ordered Denver International Airport to pay $33.5 million for noise violations that affected nearby neighborhoods during a three-year period starting in 2014.

Jefferson County District Judge Christie Bachmeyer ruled that DIA did not properly monitor aircraft noise, violating an intergovernmental agreement with Adams County dating back to the late 1980s, The Denver Post reported. The ruling was handed down Friday and made public Monday.

Bachmeyer said the airport must now pay $500,000 for each of the 67 violations over the three-year period from 2014 through 2016.

Adams County argued that the airport relied on an arcane and outdated noise modeling system, rather than actual ground measurements, to gauge airport noise. The county, along with the cities of Thornton, Aurora and Brighton, sued DIA in 2018 over the noise issue, which affected long-established neighborhoods west and south of the airport. The case went to trial in Jefferson County last fall.

Denver had agreed to measure and minimize aircraft noise as part of its annexation of land in Adams County back in the 1980s for the 53-square-mile (137-square-kilometer) airport, the county argued at trial.

“Adams County was willing to take on the burdens of having an international airport as long those burdens were mitigated,” County Commissioner Steve O’Dorisio said Monday.

DIA spokeswoman Stacey Stegman said Monday that airport leaders are “disappointed in the decision and are considering next steps.” She did not say if that would include an appeal.

Airport officials have argued that as aviation technology advanced and planes became quieter, the municipalities feared money generated from excessive noise fines would dry up — precipitating the most recent litigation.