The label is the law. Read your product's label before you mix or apply; the rates here come from the labels listed under Sources.
- Active ingredient
- 2,4-D (2,4-dichlorophenoxyacetic acid), sold as salts and esters (CAS 94-75-7)
- Chemical class
- Phenoxy auxin-type herbicide; its toxicity and behavior in the environment depend on whether it is the acid, a salt or an ester.[1][3]
- Mode of action
- WSSA Group 4: Synthetic auxins (phenoxycarboxylic acids)[3]
- Signal word
- Amine 400 2,4-D Weed Killer (also sold as Hi-Yield 2,4-D Amine No. 4): Danger[2]
How it works
2,4-D makes the cells in a plant's water- and nutrient-carrying tissue divide and grow without stopping; herbicides that act this way are called auxin-type herbicides.[1]
In soil, half of it usually breaks down within 1 to 14 days, mostly through bacteria, though low levels have been found in shallow groundwater and streams.[1]
Storing and disposing of the concentrate
The label requires storing it in the original container in a locked area children and pets cannot reach, and keeping it from freezing.[2]
Leftover concentrate, spray mix and rinsate are classed as acutely hazardous wastes; if they cannot be used up according to the label, contact your state pesticide agency for disposal guidance.[2]
Where it is used
Use on established lawns of bluegrass, perennial ryegrass or fescue when weeds are actively growing, not on newly seeded areas or on a new lawn until it has been mowed twice, and delay mowing before and after treatment.[2]
Zoysiagrass, bermudagrass, St. Augustinegrass, dichondra and clovers can be severely injured, so only spot-treat weeds in those lawns; never use it on bentgrass greens or broadleaf groundcovers.[2]
Do not apply when temperatures are above 90°F and humidity is high, and do not spray where drift can reach gardens or other susceptible broadleaf plants; even invisible drift can injure them.[2]
Products and registrations
| Product | Registrant | EPA Reg. No. | Active % | Formulation | Signal word |
|---|---|---|---|---|---|
| Amine 400 2,4-D Weed Killer (also sold as Hi-Yield 2,4-D Amine No. 4)[2] | PBI/Gordon Corporation | 2217-2 | 46.47% | soluble concentrate (amine salt) | Danger |
Label rates
| Product | Use | Pests | Rate |
|---|---|---|---|
| Amine 400 2,4-D Weed Killer (also sold as Hi-Yield 2,4-D Amine No. 4) | Established lawns: cool-season grasses such as bluegrass, perennial ryegrass and fescue | Broadleaf weeds | 1.0–1.1 fl oz per 1,000 sq ft[2] With a hand sprayer, 1 fl oz (2 Tbs) in 1 gallon of water treats 1,000 sq ft. The label maximum is 1.1 fl oz per 1,000 sq ft per application and two broadcast applications a year. Spot-treat only on zoysia, bermuda, St. Augustine and other creeping grasses. |
How to apply it, step by step
1. Protective gear
- This concentrate carries the DANGER signal word: it is corrosive and causes irreversible eye damage. Wear goggles or a face shield, a long-sleeved shirt, long pants, shoes, socks and chemical-resistant gloves, plus a chemical-resistant apron while mixing or cleaning up.[2]
- Throw away clothing soaked with the concentrate rather than washing it, and wash with soap and water after handling.[2]
2. Before you spray
- Use it on established lawns of bluegrass, perennial ryegrass or fescue; only spot-treat weeds in zoysia, bermuda, St. Augustine, dichondra or clover lawns, which it can badly injure.[2]
- Don't spray when it's above 90°F and humid, or where drift could reach gardens, shrubs or other broadleaf plants; even invisible drift can injure them.[2]
- Never apply it through an irrigation system.[2]
3. Mixing
- With a hand sprayer, mix 2 tablespoons (1 fl oz) in 1 gallon of water to treat 1,000 sq ft, or 1 tablespoon in half a gallon for 500 sq ft.[2]
4. Applying
- Spray weeds that have emerged and are actively growing; deep-rooted perennials may need a repeat application.[2]
- Stay within the label limits: no more than 1.1 fl oz per 1,000 sq ft per application and two broadcast applications a year.[2]
5. After you spray
- Keep people and pets out of the treated area until the spray has dried.[2]
First aid
- In the eyes, hold them open and rinse slowly and gently with water for 15 to 20 minutes, removing contact lenses after the first 5 minutes, and call a poison control center or doctor.[2]
- If swallowed, call a poison control center or doctor immediately, have the person sip a glass of water if able, and don't induce vomiting unless told to; on skin or clothing, take off the clothing and rinse skin with plenty of water.[2]
Storage, spills and disposal
- Store it in its original container in a locked area children and pets can't reach, and keep it from freezing.[2]
- Leftover concentrate, spray mix and rinse water are acutely hazardous waste: if you can't use them up as the label directs, contact your state pesticide or environmental agency for disposal guidance.[2]
From the safety data sheet
- The product is a liquid with an amine odor.[4]
- The SDS classifies it as harmful if swallowed, as causing serious eye damage, and as able to cause an allergic skin reaction.[4]
- For eye contact, flush with plenty of water right away, remove contact lenses after the first flushing, keep flushing for at least 15 minutes and call a physician; wash skin immediately with soap and plenty of water while removing contaminated clothing.[4]
- Soak up spills with an inert absorbent such as sand or sawdust and keep the product out of drains, sewers and surface water; the SDS rates it toxic to aquatic life with long-lasting effects.[4]
- Keep it in labeled, tightly closed containers in a cool, well-ventilated place, away from strong acids, bases and oxidizers.[4]
Safety and environmental hazards
People
This amine concentrate carries the signal word DANGER: it is corrosive and causes irreversible eye damage, and the label requires goggles or a face shield, chemical-resistant gloves and an apron when mixing. NPIC says the acid and salt forms can cause severe eye irritation, and EPA decided in 2004 that 2,4-D could not be classified for cancer because there was not enough data.[2][1]
Pets
Pets are exposed by walking on or eating grass still wet with spray and then grooming; dogs may be more sensitive to 2,4-D than other animals, and dogs and cats that swallowed products have vomited, drooled, staggered or had convulsions. Stay off treated grass until the leaves are dry.[1]
Bees and pollinators
NPIC reports that 2,4-D is practically non-toxic to honeybees and is not expected to harm other beneficial insects.[1]
Fish and water
The label says it is toxic to fish and aquatic invertebrates; NPIC notes that ester forms can be very toxic to fish while salt forms like this amine may be only slightly toxic, and that aquatic animals grow more sensitive as water warms.[2][1]
Common questions
- How much 2,4-D per gallon for my lawn?
- This label calls for 1 fluid ounce (2 tablespoons) in 1 gallon of water to treat 1,000 square feet.[2]
- Will 2,4-D kill my St. Augustine or bermuda grass?
- It can injure them severely. The label says to only spot-treat weeds in zoysia, bermuda, St. Augustine, dichondra or clover.[2]
- When is it too hot to spray 2,4-D?
- The label says not to apply when temperatures exceed 90°F and humidity is high.[2]
- Is 2,4-D safe for dogs?
- Keep dogs off treated grass until it is dry; NPIC notes dogs may be more sensitive to 2,4-D than other animals.[1]
Sources
- National Pesticide Information Center, “2,4-D General Fact Sheet.” npic.orst.edu/factsheets/24Dgen.html (accessed 2026-10-06)
- U.S. EPA Pesticide Product Label System, “Amine 400 2,4-D Weed Killer label, EPA Reg. No. 2217-2 (EPA-stamped, Aug. 18, 2021).” www3.epa.gov/pesticides/chem_search/ppls/002217-00002-20210818.pdf (accessed 2026-10-06)
- Weed Science Society of America, “Summary of Herbicide Mechanism of Action According to the Weed Science Society of America.” wssa.net/wp-content/uploads/WSSA-Mechanism-of-Action.pdf (accessed 2026-10-06)
- PBI-Gordon Corporation, “Amine 400 2,4-D Weed Killer Safety Data Sheet (PBI-Gordon Corporation, EPA Reg. No. 2217-2, revised April 8, 2015; copy hosted by the National Interagency Fire Center, Great Basin Coordination Center).” gacc.nifc.gov/gbcc/dispatch/id-eic/admin/SDS%20PDFs/Amine%20400%202,4-D%20Weed%20Killer_%20PBI%20Gordon%20Corp_SDS_3.12.15.pdf (accessed 2026-10-17)