EPA Demands Answers From Start-Up Launching Sulfur Dioxide into Air

April 15, 2025

Contact Information

EPA Press Office (press@epa.gov)

WASHINGTON – The U.S. Environmental Protection Agency’s (EPA) Office of Air and Radiation (OAR) submitted a demand for information to a start-up company calling themselves “Make Sunsets,” which is launching balloons filled with sulfur dioxide (SO2) seeking to geoengineer the planet and generate “cooling” credits to sell. This issue was initially identified in 2023 during the last Administration, but no action was taken to find out more about this questionable start-up and activity. 

“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,” said EPA Administrator Zeldin. “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.” 

Make Sunsets is already banned in Mexico. Their website states they want to scale this activity significantly and have already conducted over 124 deployments. It is unclear where the balloons are launched and where the SO2 is from. Furthermore, it is not known if the company has been in contact with any state, local or federal air agencies. Thus, EPA is submitting a demand for information to get answers and plans to take additional actions as necessary. 

Under Section 114 of the Clean Air Act (CAA), EPA is authorized to require facilities to provide information about their operations.  

The agency is requesting a response within 30 days. 

Sulfur dioxide has been regulated by EPA since 1971 as part of the National Ambient Air Quality Standard (NAAQS) program. Sulfur dioxide can harm human health and the environment. Short-term exposures to SO2 can harm the human respiratory system and make breathing difficult. People with pulmonary diseases, particularly children, are sensitive to the effects of SO2. Additionally, SO2 can react in the atmosphere leading to acid rain or form particles that harm health and impair visibility.