Ceteareth-11

Ceteareth-11 is a nonionic surfactant made by reacting cetearyl alcohol (a blend of C16 and C18 fatty alcohols) with about eleven units of ethylene oxide. In car care it is the workhorse emulsifier: it lets an oil carrier, water, and a mineral abrasive coexist as one stable cream that will not separate on the shelf, and it helps the residue wipe off with a microfiber rather than smearing.

The number after the name is the average count of ethylene oxide units. Lower numbers (Ceteareth-6) are more oil-loving; higher numbers are more water-loving. Formulators often use two grades together to tune how a compound wets a pad and how easily it releases.

Two things matter for safety. First, the neat higher-ethoxylate material is classified for serious eye damage, which is why compounds built on it commonly carry an eye-irritation code even after dilution. Second, ethoxylation is done with ethylene oxide, and a trace residual of that reagent remains in the finished surfactant. Ethylene oxide is on California's Proposition 65 list, so products disclosing a ceteareth under the California Cleaning Product Right to Know Act generally list it as a nonfunctional constituent.