Onterris, Inc. ONT

What this company does

The company provides environmental services to private and public sector clients across the life cycle of their needs, including launching new projects, maintaining operations, decommissioning operations, rehabilitating assets, managing the impacts of climate change, and responding to environmental disruption. As of December 31, 2025, it had approximately 3,500 employees, of whom approximately 2,650, or 76%, were based in the United States, with approximately 730 in Canada and approximately 120 in Australia. Its largest client accounted for approximately 17.8% of revenue for the fiscal year ended December 31, 2025, generated from more than 285 separate projects that included a large emergency response event. The company organizes its operations into three business segments: Assessment, Permitting and Response; Measurement and Analysis; and Remediation and Reuse. Its Assessment, Permitting and Response segment provides scientific advisory and consulting services for environmental assessments, environmental emergency response and recovery, toxicology consulting, and environmental audits and permits covering current operations, facility upgrades, new projects, decommissioning projects and development projects. Its Measurement and Analysis segment tests and analyzes air, water and soil to determine concentrations of contaminants and their toxicological impact on flora, fauna and human health, and offers source and ambient air testing and monitoring, leak detection, and multi-media laboratory services covering air, soil, stormwater, wastewater and drinking water analysis. Its Remediation and Reuse segment provides clients with engineering, design and implementation services, primarily treatment technologies that treat contaminated water and remove contaminants from soil. The company traces its inception to 2012.

Written from the business description in Onterris, Inc.'s annual report to the U.S. Securities and Exchange Commission, filed 26 February 2026. Every sentence was checked against that document before publication.