Perma-Fix Environmental Services, Inc.

Item 8.01 – Other Events. On September 22, 2026, Perma-Fix Environmental Services, Inc. (the “Company”) filed a Current Report on Form 8-K that included as Exhibit 99.1 the Company’s “Investor Presentation, September 2026” (the “Original Presentation”). The Company is filing this Current Report on Form 8-K/A to provide a revised version of that presentation (the “Revised Presentation”), which is attached to this Report as Exhibit 99.1 and incorporated herein by reference. The Revised Presentation revises the Company’s presentation of the Direct-Feed Low-Activity Waste (“DFLAW”) program on slides 9 and 16. Following investor inquiries, the Company concluded that the Original Presentation did not adequately portray the values it was intended to present. Slide 9 now states that the Company continues to reference the U.S. Department of Energy’s (“DOE”) estimate of 8,000 cubic meters of effluent generated annually at the site, which the Company estimates would equate to approximately $70 million in annual DFLAW-related revenue at full operation, that DOE has not revised that estimate, and that timing depends on how quickly DFLAW ramps toward design capacity. On slide 16, the DFLAW lines have been revised to present combined DFLAW waste (Effluent Management Facility (“EMF”) effluent and dry waste) of approximately 4,000 cubic meters, estimated at approximately $35 million of annual revenue, based on an assumption that DFLAW reaches 50% of production capacity in 2027. The DFLAW - EMF line is a component of that amount and is not additive, and production levels at DFLAW could vary and are not known at this time. The 200 East lines have been combined, and the initial 200 East amount has been revised to approximately $28.8 million to reflect a consistent pricing assumption across the volumes shown. The table states that revenue assumes base rate pricing for standard waste, with waste having higher organics, metals or radioactivity carrying higher pricing. As revised, the 2028 illustrative run rate shown on slide 16 is approximately $97.4 million. The Revised Presentation supersedes the Original Presentation and is posted to the Company’s website. The Revised Presentation contains forward-looking statements, which are subject to the cautionary statements included in the Revised Presentation and the risk factors described in the Company’s filings with the Securities and Exchange Commission.