2,4-D

Synonyms

2,4-Dichlorophenoxyacetic acid; (2,4-Dichloor-fenoxy)-azijnzuur [Dutch]; (2,4-Dichlor-phenoxy)-essigsaeure [German]; (2,4-Dichlorophenyloxy)acetic acid; 2,4-D acid; 2,4-Dwuchlorofenoksyoctowy kwas [Polish]; 2,4-PA; Acetic acid, (2,4-dichlorophenoxy)-; Acide 2,4-dichloro phenoxyacetique; Acide 2,4-dichloro phenoxyacetique [French]; Acido(2,4-dicloro-fenossi)-acetico; Acido(2,4-dicloro-fenossi)-acetico [Italian]; Acme LV 4; Acme LV 6; Agricorn D; Agrotect; Amoxone; B-Selektonon; BH 2,4-D; Barrage; Brush-rhap; Butoxy-D 3: 1 Liquid emulsifiable Brushkiller LV96; Butoxy-D 3: 1 Liquid emulsifiable Brushkiller LV96 [Canada]; Chipco turf herbicide "D"; Chloroxone; Citrus fix; Crop rider; Croprider; De-Pester Ded-Weed LV-2; Debroussaillant 600; Ded-Weed LV-69; Deherban; Dichlorophenoxyacetic acid; Dicopur; Dormon; Dormone; ENT 8,538; Emulsamine; Emulsamine BK; Emulsamine E-3; Envert DT; Esteron 44 weed killer; Esteron 76 BE; Estone; Fernesta; Fernimine; Ferxone; Foredex 75; Green Cross Weed-No-More "80"; Hedonal; Hedonal (the herbicide); Herbidal; Hivol-44; Ipaner; Kwas 2,4-dwuchlorofenoksyoctowy [Polish]; Kwasu 2,4-dwuchlorofenoksyoctowego [Polish]; Kyselina 2,4-dichlorfenoxyoctova [Czech]; Lawn-keep; Macondray; Macrondray; Miracle; Mota Maskros; Moxon; Moxone; Netagrone; Netagrone 600; Pennamine D; Phenox; Phenoxyacetic acid, 2,4-dichloro-; Pielik; Planotox; Plantgard; R-H Weed Rhap 20; Red Devil Dry Weed Killer; Rhodia; Scott's 4-XD Weed Control; Silvaprop 1; Superormone concentre; Tributon; U 46DP; U-5043; Vergemaster; Verton 2D; Verton 38; Vidon 638; Visko-rhap low drift herbicides; Visko-rhap low volatile 4l; Weed TOX; Weed-Ag-Bar; Weed-B-gon; Weed-Rhap A-4; Weed-Rhap B-266; Weed-Rhap B-4; Weed-Rhap I-3.34; Weed-Rhap LV-4-0; Weed-rhap; Weedatul; Weedez Wonder BAR; Weedone; Weedone 100 Emulsifiable [Canada]; Weedone LV4; Weedtrol; 2,4-D [Chlorophenoxy herbicides]; 2,4-D, salts and esters; Acetic acid, (2,4-dichlorophenoxy)-, salts and esters; [ChemIDplus] UN2765; 2,4D

Category

Herbicides, Chlorophenoxy

Description

White to yellow, crystalline, odorless powder. [herbicide]; [NIOSH] White solid; Primary formulations are as amine salt in aqueous solution and as ester in emulsifiable concentrate; [Reference #2]

Sources/Uses

Used as selective broadleaf herbicide with minor applications as a plant growth regulator and fungicide; Active ingredient in approximately 660 agricultural and home use products; [Reference #2] Other agricultural uses include conifer release, to enhance red color in potatoes, for uniform fruit ripening in tomatoes, and to increase latex output in old rubber trees; Was used as a component of the military defoliant Agent Orange; [HSDB] Since 1987, process changes have reduced the chance of 2,4-D being contaminated with chlorinated dioxins; [ACGIH]

Comments

Poisoning by ingestion of large amounts of chlorophenoxy acids has been reported. Patients developed severe metabolic acidosis and multiple organ failure. [EPA Pesticides, p. 95] There is limited positive data that 2,4-D causes birth defects in experimental animals. The data from human studies for skeletal defects is strongly negative. [ATSDR Case Studies # 29] In poisoning cases by ingestion of chlorophenoxy compounds, elevated liver enzymes and rhabdomyolysis with secondary renal failure have been reported; [HSDB] A skin, eye, and respiratory tract irritant; Exposure to high levels may cause nervous system effects; [ICSC] Rapidly decomposed by water; [CAMEO] Shown to increase congenital malformations in mice, rats, hamsters, and sheep, although these effects not reproduced in other studies of mice or rabbits; Most human data pertains to the mixture Agent Orange; [REPROTOX] "TLV Basis" is thyroid effects and kidney tubular damage; In 2-year feeding studies of rats, caused histopathological kidney changes and depressed serum T4 levels (females only) at 45 mg/kg (the highest dose tested); [ACGIH]

Reference Link #1

Biomedical References

No

Yes

10 mg/m3, inhalable particulate matter

10 mg/m3

2 mg/m3, inhalable fraction (including salts and esters)

100 mg/m3

Excerpts from Documentation for IDLHs

Human data: It has been reported that the lethal oral dose ranges from 80 to 800 mg/kg [Dalgaard-Mikkelsen and Poulsen 1962; Dudley and Thapar 1972]. [Note: Oral doses of 80 to 800 mg/kg are equivalent to a worker being exposed to about 3,700 to 37,000 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]

1.4E-07 mm Hg

LC50 (rat) > 1,790 mg/m3

Explanatory Notes

The Guide in the Emergency Response Guidebook is for "Phenoxy pesticide, solid, toxic."

Whole body: 220 hours (reduced to 4-7 hours by urinary alkalinization); mean plasma 1/2 life: 12 hours; [TDR, p. 510]

Reference Link #2

Hepatoxic (a) from occupational exposure (secondary effect) or (b) in animal studies or in humans after ingestion

Yes

Yes

Possible (2b)

Not Classifiable

Processes

Industrial Processes with risk of exposure:

• Farming (Pesticides)