Involved in degradation of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). Is also able to degrade 2-methyl-4-chlorophenoxyacetic acid and 3-chlorobenzoic acid. (2,4-dichlorophenoxy)acetate + 2-oxoglutarate + O2 = 2,4-dichlorophenol + CO2 + glyoxylate + succinate Binds 1 Fe(2+) ion per subunit. Activated by ascorbate. Xenobiotic degradation; (2,4-dichlorophenoxy)acetate degradation. Hydroxylated on Trp-113; inactivates the enzyme. Belongs to the TfdA dioxygenase family.