Ethylene oxide and Dioxan in Triton X 100 and Tween 20?

Dear Experts,

I just noticed that some preparations of Tween 20 and Triton X 100 are
certified "free of ethylen oxide and dioxan". They probably are traces
from the synthesis of the poly(ethyleneglycol) residues present in the
substance. I just wonder how that stuff should affect any usual lab
application.

Ethylene oxide should be immediately hydrolyzed by water to ethandiol,
dioxan probably is a made of 2x ethylene oxide or a byproduct of
ethylene oxide synthesis) and is water soluble, too. Maybe they are
sort of toxic to cells (would you want to treat them with detergent
anyway except lysing them?).

Why should I be concerned about them as they only would occur in
smallest traces (say: 0.1% in the detergent in a 0.1% detergent
solution makes a 0.0001% solution which would be equivalent to 1
ppm)

Any clues?

Wo