As EPA Rolls Back Regulations for Large Industrial Polluters, It Finds a New Target: A Two-Person Geoengineering Startup

The U.S. Environmental Protection Agency is demanding information from a small geoengineering startup company it says is launching pollution into the air.  The EPA’s Office of Air and Radiation submitted a demand for information to Make Sunsets, which launches balloons filled with sulfur dioxide (SO₂) into the atmosphere in an attempt to lower the planet’s temperature and sell “cooling credits.” “The idea that individuals, supported by venture capitalists, are putting criteria air pollutants into the air to sell ‘cooling’ credits shows how climate extremism has overtaken common sense,”  EPA Administrator Lee Zeldin said in a written statement. “Based on Make Sunsets’ responses to our information request, we will look into all our authorities to ensure that we continue maintaining clean air for all Americans.”  David Bookbinder, the director of law and policy for the Environmental Integrity Project called the demands “ridiculous.” “It’s absolutely hilarious that Zeldin and EPA, which is doing its level-best to allow emissions to increase as much as possible—exempting industries, rolling back rules, determined to just let industrial sources put whatever they want into the atmosphere—[to say] that he’s concerned about sulfur dioxide emissions from balloons the size of three bread boxes put together.”  When released in the stratosphere, sulfur dioxide can cool the planet by reflecting sunlight back into space. However, the EPA considers SO₂ a “criteria pollutant” that can harm human health and the environment. This occurs when elevated concentrations of the pollutant occur closer to Earth, either from ground-level emissions or, potentially, if large volumes of SO₂ were used in geoengineering and subsequently fell back down to Earth. Sulfur dioxide near the Earth’s surface can cause respiratory problems and acid rain. The National Academies of Sciences, Engineering, and Medicine notes that solar geoengineering “could reduce the surface temperature of Earth, but there are many unknowns about the impacts solar geoengineering would have on ecosystems, human health, and political and economic systems.” In a Tuesday post on the social media site X (formerly Twitter), Zeldin added, “This company is polluting the air we breathe. I’ve instructed my team that we need to quickly get to the bottom of this and take immediate action.”

Meanwhile, Zeldin introduced what he called “the largest deregulatory announcement in U.S. history” on March 12 when the EPA released 31 separate actions to roll back restrictions on air and water pollution, hand over more authority to states and relinquish EPA’s mandate to act on climate change under the Clean Air Act. Make Sunsets has launched 147 balloons and sold 128,000 “cooling credits” that offset the warming equivalent to the release of 128,000 metric tons of carbon dioxide since February 2023, according to the company’s website. The emissions reductions are equal to three percent of the annual greenhouse gas emissions of one coal-fired power plant, according to the EPA’s greenhouse gas equivalency calculator.  “If this outfit continued in existence for 100 years at its pace, it would not equal in terms of sulfur dioxide what any given industrial facility puts up in two days,” Bookbinder said. “I can point him [Zeldin] to 20 facilities in the United States that are emitting sulfur dioxide in quantities that actually threaten people’s health, of which EPA couldn’t care less.” An EPA spokesperson said in a written response to Bookbinder’s comments that they were glad to see that a climate advocate was “totally on board with polluting the environment.”  The spokesperson added that ”the Trump EPA will continue to advance conservation and environmental stewardship.” Luke Iseman, the founder of Make Sunsets, said he was surprised to receive a letter from the EPA. “We’re a two-person startup with an RV as our main office,” he said. “It’s a little surprising and scary, frankly, to have the head of a very powerful federal agency declare that he’s—threatened on Twitter that he’s—targeting you for enforcement.”

The agency noted that Make Sunsets is already banned in Mexico and states on its website that they seek to scale its activity significantly. The EPA added that it is unclear where the balloons are launched from. Iseman said the Mexican government notified his company that they were considering banning them from releasing balloons in Mexico, at which point they stopped their activity there. Iseman said they release their balloons in California and Nevada and report all release activity to the National Oceanic and Atmospheric Administration, as required by federal law. In its letter to the company, the EPA sought additional information, including the altitude at which the balloons release sulfur dioxide into the atmosphere and whether any balloons have burst at ground level prior to launch. Iseman said releases occur at approximately 14 to 15 miles above the Earth and that one balloon burst at ground level at a launch in Mexico when it hit a barbed-wire fence. Iseman added that their biggest balloons hold under 2 kilograms of sulfur dioxide. “When you fly from San Francisco to New York, the plane outputs over six kilograms of SO₂,” Iseman added.  A report submitted by the company for releases from May 2023 to early January 2024 is available for download on the NOAA website for weather modification projects. Iseman said his company has submitted its 2024 report to NOAA but the agency hasn’t yet posted it on its website. “We’ve been in contact with multiple US government agencies (CIA, FBI, FAA, and NOAA),” the company states on its website. “They are aware of our business and activities.” In March 2024, Bookbinder and others petitioned NOAA to expand reporting requirements for weather modification activities, including calling for new requirements to report activity by U.S. citizens that occurs outside the United States and additional reporting related to the sale of “cooling credits.” The petition also called on the agency to go beyond reporting requirements and come up with a strategy to regulate future solar radiation management activities. “The ultimate problem is that there is no governance,” Bookbinder said. “All NOAA can do is get information, but there’s no governance on geoengineering itself. And it’s not these people [Make Sunsets] that we have to worry about. It’s when somebody says, ‘OK, I’m going to go up there and start ladling tons of stuff into the stratosphere’ and there’s no restrictions on someone doing that.” EPA’s letter to Make Sunsets comes as the Trump Administration has fired thousands of employees at the agency and may soon ask Congress to cut NOAA’s budget significantly.  Bookbinder said he is not aware of any new regulatory activity on solar geoengineering since he and others filed their petition. “I haven’t heard that anything has come of it, and I doubt, with this administration there will be,” he said.