2,4-dichlorophenoxyacetic acid (2,4-D) can result from exposure to this very common herbicide that was a part of a chemical mixture called Agent Orange, used by the U.S. during the Vietnam War to increase the visibility for war planes by destroying plant undergrowth and crops.

Herbicides are chemical agents intended to kill unwanted vegetation such as broadleaf weeds and woody plants. They are used in agriculture and on residential properties. People can be exposed to herbicides by breathing them or by skin contact from their residential use or living near application sites, and by eating contaminated food and drinking contaminated water.

- Mean urinary levels of 2,4-D among workers involved in mixing, loading, and applying this herbicide ranged from 5 to 837 μg /L.

- Median urine 2,4-D concentrations at baseline and a day after application of this herbicide were 2.1 and 73.1 μg/L for farming applicators, and 1.5 and 2.9 μg/L for their children.

- 2,4-D has a half-life of approximately 12-36 h.

Health issues:

- Neuritis, weakness, nausea, abdominal pain, headache, dizziness, peripheral neuropathy, stupor, seizures, brain damage, and impaired reflexes have been associated with dermal or oral exposure.

- 2,4-D is a known endocrine disruptor, and can block hormone distribution and cause glandular breakdown.

- It is linked to immune system damage, birth defects and reproductive issues possibly due to its frequent contamination with dioxins.