Birchtech clears all patent challenges on mercury-removal technology
Birchtech Corp. has announced that every outstanding Inter Partes Review (IPR) petition filed against its core mercury-removal patents has been resolved, with the final remaining challengers filing termination requests at the US Patent Trial and Appeal Board (PTAB). The NYSE American- and TSX-listed company says all parties previously involved in the proceedings are now permanently barred from bringing further validity challenges against its SEA sorbent technology.
The outcome brings to a close a seven-year patent enforcement campaign that the company says has so far generated approximately $37 million in licence fees and settlements from utilities since 2020. A federal jury in Delaware found against the so-called CERT defendants on all counts in March 2024, with findings of willful, inducing and contributory infringement. In December 2025, the court increased the final judgement to $78.4 million inclusive of pre-judgement interest, with post-judgement interest continuing to accrue. Collection efforts are ongoing.
The technology and its market
Birchtech's patented SEA sorbent is an activated-carbon product designed to capture mercury emissions from coal-fired power stations, a requirement under US federal environmental regulations. Mercury air-toxics rules, enforced by the Environmental Protection Agency, oblige utilities operating coal plant to deploy emissions-control systems; Birchtech argues that a meaningful share of those deployments drew on its patented chemistry without a licence.
The activated-carbon market for emissions control is a relatively mature segment, its near-term trajectory tied directly to the remaining operating life of US coal generation. Coal's share of US power generation has declined sharply over the past decade, and a substantial fraction of the remaining fleet faces retirement pressure from economics as well as regulation. That trajectory limits the long-term addressable market for coal-specific air-treatment sorbents, which is likely why Birchtech is actively pivoting its intellectual property and manufacturing expertise toward water treatment.
Strategy pivot to water and PFAS
Chief executive Richard MacPherson signalled the forward direction explicitly, stating that "the same expertise and intellectual property discipline that protected our Clean Air business is now being applied to Water." The company says it is entering the North American water treatment market with technologies targeting per- and polyfluoroalkyl substances (PFAS) — synthetic compounds widely found in industrial and municipal water systems that have drawn intensifying regulatory scrutiny in both the US and Europe.
The PFAS remediation market is at an earlier commercial stage than mercury control, but regulatory momentum is building rapidly. The US EPA finalised maximum contaminant levels for several PFAS compounds in drinking water in 2024, creating a compliance-driven demand signal for treatment technologies. Activated carbon is one of the established removal pathways, alongside ion-exchange resins, though cost and regeneration logistics vary considerably by application.
From an investor standpoint, the resolution of the IPR proceedings stabilises Birchtech's IP position and removes a litigation overhang, but the more consequential question is whether the company can convert its air-treatment chemistry and the $78.4 million judgement into a credible water-treatment business before the coal-plant market contracts further. The company described its balance sheet as "bolstered" but did not provide updated cash or debt figures in this release.