Silvex 2,4,5-TP
2,4,5-TP·Affects liver, kidneys
A chlorinated herbicide banned in 1985 due to dioxin contamination during manufacture. Legacy soil and groundwater contamination persists at former application sites.
2,4,5-TP
EPA limit
0.05 mg/L (MCL)
Most at risk
Well-water households near former rangeland, rice fields, sugarcane, and right-of-way spray areas
Found in
City water · Well water
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Silvex (2,4,5-TP, also called fenoprop) is a chlorophenoxy herbicide closely related to 2,4-D and 2,4,5-T. The EPA cancelled all uses in 1985 primarily because the manufacturing process produced trace amounts of 2,3,7,8-TCDD, the most toxic dioxin known. The dioxin contamination, more than the silvex itself, drove the ban.
The liver and kidneys are the primary target organs for chronic silvex exposure. Animal studies show hepatic and renal damage at sustained moderate doses. Silvex also produces developmental effects.
Because silvex was a key ingredient in formulations like Agent Orange's chemical cousins, exposure assessments at contaminated sites often consider silvex and TCDD dioxin together. The current MCL of 50 ppb addresses silvex itself; separate dioxin standards address the contamination concern.
Where it comes from
How it gets into your water
Silvex was widely used from the 1950s through the early 1980s to control broadleaf and woody weeds on rangeland, pastures, rice paddies, sugarcane, golf courses, lawns, and utility rights-of-way. The 1985 cancellation halted new use, but legacy contamination persists at heavy-application sites.
The parent compound has a moderate soil half-life and is moderately mobile in groundwater. The TCDD dioxin co-contaminant binds tightly to soil and persists for decades, so contaminated-site assessments often focus more on dioxin than on residual silvex.
Former rangeland and pastures
Heavy broadcast application pre-1985
Former rice and sugarcane fields
Aquatic weed control in flooded paddies
Right-of-way spray areas
Utility and highway vegetation management
Legacy groundwater contamination
Persists at historic application sites
Find out for yourself
Is it in your water?
Public utilities test for silvex under the EPA's primary drinking water regulations and report results in the annual Consumer Confidence Report. Detections in modern city water are rare because of the 40-year-old ban.
Well-water households in regions with historic heavy use, particularly former rice and sugarcane areas of the Gulf South and rangeland in the West, should consider testing for chlorophenoxy herbicides as a group, which catches silvex alongside 2,4-D, 2,4,5-T, and dicamba. State environmental agencies can advise on local contamination history.
The fix
How AquaOx filters it
Silvex is filtered efficiently by activated carbon. The coconut shell carbon stage in The AquaOx adsorbs chlorophenoxy herbicides as water passes through the bed, with independent testing showing reductions well above 90%.
For well-water households in regions with legacy herbicide contamination, we recommend pairing The AquaOx with our FE or RE Edition if iron or hydrogen sulfide is also present, and adding the under-sink RO for additional drinking-water polish.