Milestone is a liquid herbicide created and distributed by Dow AgroSciences. It is used to kill broadleaf weeds and, according to Dow, is specifically designed for use on ranges and pastures. Its active ingredient is aminopyralid, a chemical created and patented by Dow. Although Milestone is designed to be effective at much lower concentrations than similar herbicides, it still poses health risks to humans, particularly if ingested or applied to the skin or eyes.

Milestone herbicide may cause eye irritation, according to the product's Materials Safety Data Sheet, or MSDS. To remove Milestone from the eyes, rinse eyes thoroughly with clean water for several minutes. After the first minute or two of washing, remove any contact lenses. If eye irritation or similar eye symptoms persist, the patient should see an ophthalmologist, or his or her regular physician if an ophthalmologist is not available. To avoid eye contact, the product's Specimen Label recommends that users wear long clothing and gloves, and stand upwind of any application of Milestone.

A risk of skin irritation from exposure to Milestone herbicide also exists, according to the product's MSDS information. If you experience skin irritation from exposure to Milestone, remove your clothes and wash any areas of skin that may have come in contact with the herbicide. Contact your physician if skin irritation persists. Although there is no specific antidote for Milestone herbicide, even prolonged skin exposure is not likely to cause death, according to Dow.

Although testing has not revealed that Milestone herbicide causes any severe or long-term damage to the lungs, according to the product's MSDS information, inhalation of Milestone may still cause irritation of the respiratory system, including the lungs, in some people. Always spray or handle Milestone in a well-ventilated area, preferably outdoors. If you inhale the product, move away from the area and into a place with clean, well ventilated air. If you experience any irritation or other symptoms in your nose, mouth, throat or chest, contact a physician.