WASHINGTON — Aaron Szabo has left the Environmental Protection Agency after leading the office responsible for national air-pollution and climate regulations, creating a leadership transition while a proposed successor awaits Senate action.
The EPA said Tuesday that Szabo’s departure was effective Friday, Oct. 2. The agency did not publicly give a reason for the departure. Szabo had remained in the job after an earlier plan to leave during the summer.
Why the air office matters
Szabo led the Office of Air and Radiation, which develops and administers programs covering industrial and vehicle emissions, air-quality monitoring, facility permitting, radiation protection, indoor air and the stratospheric ozone layer. The office is central to implementation of the Clean Air Act and parts of the Atomic Energy Act.
During Szabo’s tenure, the Trump administration moved to unwind a number of climate and air-pollution rules, including the 2009 finding that greenhouse gases endanger public health and welfare. That finding has served as a legal foundation for federal regulation of climate pollution.
The office also worked on changes affecting power plants, vehicles, oil and gas operations and renewable-fuel requirements. Those actions remain subject to separate rulemaking schedules and, in some cases, court challenges; Szabo’s departure does not by itself cancel or complete them.
EPA cites deregulation; its savings figure is an agency claim
In a statement provided to Reuters, EPA thanked Szabo for advancing the administration’s agenda and said his office helped produce what the agency called the largest deregulatory action in U.S. history. EPA valued the projected deregulatory savings during his tenure at more than $1.6 trillion.
That number is the agency’s estimate, not a realized cash total, and it depends on EPA’s assumptions about future compliance costs and the duration of the policy changes. The figure should therefore be read as an administration claim rather than an independently audited result.
Justin Schwab nomination remains pending
The White House sent Justin Schwab’s nomination for an EPA assistant administrator position to the Senate on Sept. 28. EPA said he has been nominated to replace Szabo. Schwab is a senior adviser to Administrator Lee Zeldin.
A nomination is not the same as confirmation. Until the Senate acts and the agency completes the transition, day-to-day authority may be handled by an acting official under federal succession rules. EPA had not identified an acting air-office chief in its public statement.
Reuters reported the departure and EPA response on Oct. 6. The White House nomination notice is dated Sept. 28. An EPA biography published July 24, 2025 describes Szabo’s office and its statutory responsibilities.
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Featured image: the U.S. Capitol in Washington, photographed by Caleb Perez via Unsplash. The image is illustrative.