Sodium Dodecyl Diphenyl Ether Disulfonate

Benzene, 1,1'-oxybis-, tetrapropylene derivs., sulfonated, sodium salts (CAS 119345-04-9) is a diphenyl-ether-disulfonate-class anionic surfactant (commercially known under trade names such as Dowfax) used as a wetting agent and emulsifier in industrial and automotive-care cleaning formulations.

SDS ecological data shows genuine aquatic toxicity at the ingredient level: LC50 (96-hour, rainbow trout) of 6.2 mg/L and EC50 (48-hour, Daphnia magna) of 1.64 mg/L, both well within ranges that trigger an aquatic-toxicity flag independent of whether the finished product's SDS Section 12 carries a mixture-level H4xx code. The SDS describes the substance as "inherently biodegradable" rather than "readily biodegradable," a weaker classification that does not support crediting the formula's biodegradable-credit line without further documentation.

Low bioaccumulation potential (Log Pow -2.68) means it is not expected to build up in tissue, but the acute aquatic toxicity data means any product containing this ingredient should not claim unqualified aquatic safety, and drain-destined rinse water should not be assumed benign.