Regulations last checked for updates: Oct 02, 2026

Title 40 - Protection of Environment last revised: Sep 29, 2026
§ 180.535 - Fluroxypyr 1-methylheptyl ester; tolerances for residues.

(a) General. Tolerances are established for residues of the herbicide fluroxypyr 1-methylheptyl ester, including its metabolites and degradates, in or on the commodities listed in table 1 to this paragraph (a). Compliance with the tolerance levels specified in table 1 to this paragraph (a) is to be determined by measuring only the sum of the free and conjugated forms of fluroxypyr 1-methylheptyl ester [1-methylheptyl 2-[(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetate] and its metabolite fluroxypyr [2-[(4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy]acetic acid] calculated as the stoichiometric equivalent of fluroxypyr, in or on the commodity.

Table 1 to Paragraph (a)

Commodity Parts per million
Barley, forage12
Barley, grain0.5
Barley, hay20
Barley, straw12
Cattle, fat0.1
Cattle, kidney1.5
Cattle, meat byproducts0.1
Corn, field, forage1
Corn, field, grain0.02
Corn, field, stover0.5
Corn, sweet, forage1
Corn, sweet, kernel plus cob with husks removed0.02
Corn, sweet, stover2
Fruit, pome, group 110.02
Garlic, bulb0.03
Goat, fat0.1
Goat, kidney1.5
Goat, meat0.1
Goat, meat byproducts0.1
Grain, aspirated fractions0.6
Grass, forage, fodder and hay, group 17, forage120
Grass, forage, fodder and hay, group 17, hay160
Hog, fat0.1
Hog, kidney1.5
Hog, meat0.1
Hog, meat byproducts0.1
Horse, fat0.1
Horse, kidney1.5
Horse, meat0.1
Horse, meat byproducts0.1
Milk0.3
Millet, forage12
Millet, grain0.5
Millet, hay20
Millet, proso, straw12
Oat, forage12
Oat, grain0.5
Oat, hay20
Oat, straw12
Onion, bulb0.03
Rice, bran3
Rice, grain1.5
Shallot, bulb0.03
Sheep, fat0.1
Sheep, kidney1.5
Sheep, meat0.1
Sheep, meat byproducts0.1
Sorghum, grain, forage2
Sorghum, grain, grain0.02
Sorghum, grain, stover4
Teff, forage12
Teff, grain0.5
Teff, hay20
Teff, straw12
Wheat, forage12
Wheat, grain0.5
Wheat, hay20
Wheat, straw12

(b) Section 18 emergency exemptions. [Reserved]

(c) Tolerances with regional registrations. [Reserved]

(d) Indirect or inadvertent residues. [Reserved]

[63 FR 52169, Sept. 30, 1998, as amended at 64 FR 22799, Apr. 28, 1999; 66 FR 37598, July 19, 2001; 66 FR 47971, Sept. 17, 2001; 67 FR 46884, July 17, 2002; 67 FR 60146, Sept. 25, 2002; 68 FR 75438, Dec. 31, 2003; 69 FR 2074, Jan. 14, 2004; 70 FR 3649, Jan. 26, 2005; 70 FR 7047, Feb. 10, 2005; 71 FR 76204, Dec. 20, 2006; 72 FR 73635, Dec. 28, 2007; 78 FR 3333, Jan. 16, 2013; 83 FR 29706, June 26, 2018; 91 FR 8113, Feb. 20, 2026]
authority: 21 U.S.C. 321(q), 346a and 371
source: 36 FR 22540, Nov. 25, 1971, unless otherwise noted.
cite as: 40 CFR 180.535