Boulder County and Superior sue Jefferson County over Rocky Mountain Airport, citing lead exposure and noise pollution

Boulder County and the Town of Superior have jointly filed a lawsuit against Jefferson County for its operation of the Rocky Mountain Metropolitan Airport. The lawsuit alleges the airport exposes Boulder County residents to lead from the fuels used in aircraft and excessive noise due to the high volume of traffic the airport sees.

Rocky Mountain Metropolitan Airport is located in Broomfield, though Superior lies less than a mile away. And because of prevailing wind patterns, the lawsuit states, a majority of flights use a runway that necessitates planes flying over Superior for landings and takeoffs. In 2023, according to the lawsuit, Rocky Mountain averaged more than one take off or landing every two minutes for the entire year, with this rate expected to continue increasing.

While most of the planes using the airport do not use fuel containing lead, enough do to negatively impact nearby residents’ health, the lawsuit argues.

“On a day in which the Airport experienced approximately 1,400 operations, the Town’s airborne lead levels appear to be significantly higher than measurements that had been taken in the Town on a day with little to no overflight activity,” the lawsuit states. This is a concern because there is no safe amount of lead exposure, especially for children’s cognitive development, according to the Environmental Protection Agency.

On the Town of Superior’s website, several documents detail airborne tests conducted in Superior and surrounding cities and towns. The report dated June 16, 2023, concluded that there were no detectable levels of airborne lead particles above the laboratory reporting limit on the days sampled. Similar findings were reported in Superior on Jan. 25, 2024, in Louisville on Dec. 8, 2023, and in Lafayette on Nov. 20, 2023. Despite fluctuations, including higher levels in May 2023 compared to January 2024, potentially linked to increased aircraft traffic in the summer, all recorded levels remained below the National Ambient Air Quality Standards established by the federal Clean Air Act. 

However, the lawsuit asserts, “Jefferson County knows, or should know, that lead particulates in piston-engine aircraft emissions stemming from operations at the Airport pose an unreasonable hazard to Plaintiffs’ residents.” Piston-engine aircraft tend to burn lead-containing fuel. They are smaller planes often used for training new pilots or recreational use. Four flight schools operate at Rocky Mountain and almost all of their planes are piston-engine aircraft.

The lawsuit addresses airport noise, asserting that considerable aircraft noise increases the risk of heart disease, namely through the disruption and fragmentation of sleep. It suggests that eliminating “touch-and-go” operations, where an aircraft lands and takes off without stopping, could mitigate these effects. According to the lawsuit, many touch-and-gos at Rocky Mountain also involve lead-burning piston-engine aircraft, contributing to lead exposure for Superior residents. The lawsuit states that flight schools, primarily training new pilots, conduct almost exclusively these touch-and-gos.

“Our residents have had enough,” said Mark Lacis, mayor of the Town of Superior. “Jefferson County knows there is a problem and they could solve it immediately by eliminating touch-and-go operations by piston-engine aircraft. If Jefferson County won’t abate this nuisance voluntarily, we’ll have the Courts require it.”

This lawsuit comes as Boulder debates whether to close the Boulder Municipal Airport potentially in favor of building housing. Complaints about the Boulder airport have included noise and lead pollution.