Jet engine condensation trails contain metal nanoparticles and sulfur that form lingering lines in the troposphere that disperse and form cirrus cloud cover that blocks the sun and sky when the air is cold and wet enough.

These lines are often referred to as "chemtrails," though the term can be misleading and imply the trails are mostly caused by independent spray apparatuses attached to aircraft.

There is ongoing debate (here) among the anti-geoengineering community as to whether the cause of these sun- and sky-blocking emissions is jet engine exhaust or independent sprayers.

The FAA, NASA, and NOAA have officially admitted that jets emit substances that linger in the sky and alter the weather.

The EPA's new move follows the revelation that Rainmaker, a drone-based cloud seeding startup backed by Peter Thiel's elite fellowship, had active government clearance to deploy weather-modifying chemicals over Texas just days before historic July 2025 floods killed more than 60 people.

"EPA created these new online resources to communicate everything the agency knows about the latest science, research and other information regarding contrails and geoengineering," the Thursday press release reads. "EPA is committed to total transparency with the American public on these topics."

EPA Administrator Lee Zeldin emphasized that Americans "have legitimate questions about contrails and geoengineering, and they deserve straight answers" and his team is "publishing everything EPA knows about these topics on these websites."

The agency's new online resource on condensation trails (contrails) "explains the science behind the aerial phenomenon and addresses myths and misconceptions that have persisted for decades," according to the press release.

"The new webpage also addresses head-on various claims that these occurrences are actually an intentional release of dangerous chemicals or biological agents at high altitudes for a variety of nefarious purposes, including population control, mind control, or attempts to geoengineer Earth or modify the weather."

It's worth noting the EPA's contrail resource page does state that persistent contrails "can interact with wind and clouds to form cirrus clouds" and that "persistent contrail clouds could have a small net warming effect."

These cirrus clouds are described as "thin, wispy clouds that are common at high altitudes."