Hazen Article on Disinfection Byproduct Research Published in AWWA Water Science

(DENVER, CO – April 2, 2026) – Hazen Associate Eric S. Peterson, PhD, PE and Associate Vice President Ben Stanford, PhD have co-authored an article, which highlights priority research topics related to disinfection byproducts (DBPs), that was recently published in AWWA Water Science.

The paper, titled “Disinfection Byproducts: Health Risks, Occurrence, Control, and Implications for Regulatory Revision,” details the research that is needed to better understand unregulated DBPs, which in turn will help inform effective future regulations. The article is timely, as potential changes to the set of drinking water regulations collectively called the Microbial and Disinfection Byproduct (M/DBP) Rules are on the horizon.

The U.S. Environmental Protection Agency (EPA) is undergoing a revision of the M/DBP Rules with the goal of strengthening public health protection. Periodic updates to these rules are necessary to reflect advances in scientific understanding of which DBPs pose meaningful human health risks and to ensure that treatment requirements reduce those risks in a cost-effective and equitable manner.  

There are over 700 known DBPs. While the scientific community’s understanding of some of their potential health risks has grown, there are still lingering uncertainties about many of these chemical compounds. Research conducted over the past two decades has indicated that some currently unregulated DBPs that often form in drinking water could be more harmful than two types of regulated DBPs—trihalomethanes (THMs) and haloacetic acids (HAAs). Additional research is needed focusing on translating observations from laboratory cell assays into human health risk that may be appropriately addressed through regulations.

This article summarizes the state of the science for both regulated and unregulated DBPs related to the potential M/DBP Rule changes, discusses the regulatory implications of these advancements, and identifies research priorities to support regulatory revisions. This research is important for water utilities to be aware of, as many cost-effective DBP compliance strategies used to control THMs and HAAs are not always effective for other types of DBPs. As the EPA increases its regulatory focus on emerging DBPs, utilities may want to explore and consider treatment strategies that would achieve compliance with potential future regulations in their current decision-making.

AWWA Water Science is an interdisciplinary journal of peer-reviewed research and is produced through the American Water Works Association. Hazen’s Dr. Peterson and Dr. Stanford co-authored the article in collaboration with other industry experts. The full article is available to AWWA Water Science subscribers on the American Water Works Association website.