Cancer concern was part of my motivation.
The International Agency for Research on Cancer classifies glyphosate as probably carcinogenic to humans, Group 2A, and 2,4-D as possibly carcinogenic to humans, Group 2B. These are cancer-hazard classifications, not a statement that a particular labeled lawn exposure will cause cancer. The U.S. EPA has reached a different conclusion for glyphosate, saying its earlier assessment found no human-health risks of concern from labeled uses, and EPA is updating that assessment in 2026. I saw the disagreement itself as a reason to ask whether routine broadcast treatment can be reduced when a precise alternative is possible.




