Is exposure to the odor of 2,4-D hazardous?
Pure 2,4-D is odorless. Odor associated with the application of 2,4-D comes from a small amount of the primary breakdown product, 2,4-dichlorophenol (DCP).

Another odor may come from a small amount of dimethylamine, a neutralizing agent of the 2,4 D formulation. Both of these compounds possess extremely low toxicity as a vapor, though low levels can be quite odorous. Government agencies have indicated low toxicological concern for inhalation of 2,4-D.

Odor exposure of 2,4-D is not of toxicological concern.