Water & Air / Products / Municipal Chlorination Byproducts — Trihalomethanes (THMs) and Haloacetic Acids (HAAs), Chloroform, Bladder Cancer Association (Disinfection Byproduct Rule)

Municipal Chlorination Byproducts — Trihalomethanes (THMs) and Haloacetic Acids (HAAs), Chloroform, Bladder Cancer Association (Disinfection Byproduct Rule) — water/air safety profile

Moderate risk

Municipal water chlorination, which protects 300+ million Americans from waterborne pathogens, produces disinfection byproducts (DBPs) when chlorine reacts with naturally occurring organic matter (humic and fulvic acids) in source water.

What is this product?

Municipal water chlorination, which protects 300+ million Americans from waterborne pathogens, produces disinfection byproducts (DBPs) when chlorine reacts with naturally occurring organic matter (humic and fulvic acids) in source water. The two regulated DBP classes are trihalomethanes (THMs: chloroform, bromodichloromethane, dibromochloromethane, bromoform) and haloacetic acids (HAAs: monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, dibromoacetic acid). Chloroform (CHCl3) is typically the dominant THM at 40-80% of total THM concentration. The EPA Stage 2 Disinfectant and Disinfection Byproducts Rule (2006) sets locational running annual averages (LRAAs) of 80 ug/L for total THMs and 60 ug/L for HAA5. Epidemiological meta-analyses associate long-term THM exposure (>40 ug/L) with a 20-40% increased risk of bladder cancer (Villanueva et al. 2004, 2007), and dichloroacetic acid is classified as a Group 2B possible carcinogen by IARC. DBP formation increases with higher organic matter, warmer temperatures, higher chlorine doses, and longer distribution system residence times — meaning rural systems with long pipe runs and seasonal algae often exceed limits.

What's in it

Click any compound name for its full safety profile, regulatory consensus, and exposure data.

Primary Dbp

Frequently asked questions

No FAQs generated.

Look up Municipal Chlorination Byproducts — Trihalomethanes (THMs) and Haloacetic Acids (HAAs), Chloroform, Bladder Cancer Association (Disinfection Byproduct Rule) in the water app

Search by ingredient, browse by category, or compare to alternatives in the live app.

Open in water View raw API data

Reference data, not professional advice. Aggregates publicly available regulatory and scientific information. Why we built ALETHEIA →