The Environmental Protection Agency (EPA) has opened an investigation into Make Sunsets, a controversial climate startup accused of conducting unauthorized geoengineering experiments.
EPA Administrator Lee Zeldin announced the probe on Wednesday, citing growing concerns about the company’s stratospheric sulfur dioxide releases.
Make Sunsets, a private firm based in the U.S., has admitted to launching high-altitude balloons designed to release sulfur dioxide into the upper atmosphere.
The goal, according to the company, is to reflect a portion of the sun’s rays back into space — a process known as solar radiation management — to combat global warming.
However, the method is drawing sharp criticism from scientists, regulators, and environmentalists who warn that such interventions carry significant risks.
Sulfur dioxide is a tightly regulated pollutant under the Clean Air Act and is known to cause respiratory problems, skin irritation, and contribute to the formation of acid rain.
Watch:
Its environmental and health impacts are well-documented, and unauthorized atmospheric releases could have unintended consequences on weather patterns and ecosystems.
“This isn’t just a question of innovation — it’s a matter of public safety and environmental integrity,” Zeldin said.
“We cannot allow unregulated actors to manipulate the climate without oversight.”
The investigation marks one of the first federal responses to private-sector geoengineering efforts, a field that has long operated in a legal and regulatory gray area.
Critics say Make Sunsets is effectively running climate experiments without consent or transparency, potentially setting a dangerous precedent.
The EPA is expected to evaluate whether the company’s actions violated federal environmental laws and if enforcement measures, including penalties or a possible shutdown, are warranted.
As the climate crisis intensifies, the debate over how far we should go to engineer Earth’s atmosphere is only beginning.
