Independent industry ranking reflects continued growth, innovation and leadership in solving environmental challenges.

Onterris (NYSE: ONT), a global environmental solutions company solving complex challenges for planet and progress, today announced it has advanced to No. 5 among the world's leading pure-play environmental firms in the latest Engineering News-Record (ENR) Top 200 Environmental Firms rankings.

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The recognition marks a significant milestone for Onterris, which improved from No. 7, in 2025, to No. 5 among pure-play environmental firms and continues to strengthen its position as one of the industry's leading providers of environmental consulting, engineering, remediation, testing and treatment solutions.

"This ranking is a reflection of our people, our purpose and the trust our clients place in us every day," said Vijay Manthripragada, President and Chief Executive Officer of Onterris. "As environmental challenges grow, our clients are looking for integrated solutions and the scientific expertise that helps them navigate regulatory, infrastructure and sustainability pressures while advancing their business objectives. Advancing to become the number five pure-play environmental firm in the world demonstrates the strength of our strategy and the value we deliver across the markets and communities we serve."

Published annually, ENR's Top 200 Environmental Firms rankings are widely regarded as one of the environmental industry's most respected benchmarks, evaluating firms based on environmental services revenue and performance across key environmental disciplines.

The rankings reflect growing demand for the Company’s expertise across environmental consulting, hazardous waste management, remediation, water solutions, permitting, regulatory compliance, air quality management and emerging contaminant solutions. As governments, industries and communities face increasingly complex environmental challenges, Onterris continues to help clients achieve progress through science-based, practical and innovative solutions.

"Being recognized among the top five pure-play environmental firms globally underscores the impact of our talented teams and our commitment to helping clients solve some of the world's most pressing environmental challenges," said Manthripragada. "We are proud of this achievement and remain focused on delivering solutions that protect human health, preserve natural resources and create lasting value for our clients and stakeholders."

About Onterris

Onterris is a global environmental solutions company partnering with organizations to solve complex challenges where environmental pressures, regulatory expectations and operational risks intersect. Guided by our mission to advance the way of life without compromising the integrity of our environment, we believe environmental responsibility and human progress are fundamentally connected. Our scientists, engineers, field teams and consultants apply systems thinking that unite science, data and practical expertise to deliver solutions that strengthen our clients’ resilience, mitigate risk and help protect the air, water and soil that sustain communities, while uncovering responsible paths forward for planet and progress. For more information, visit Onterris.com.

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"This ranking is a reflection of our people, our purpose and the trust our clients place in us every day," said Vijay Manthripragada, President and Chief Executive Officer of Onterris.