No doubt ethylene glycol is toxic.  That was not the point.  The point is
that it it is broken down by organisms in soil and sewer systems within a
couple of days in most cases.  Many airports do not recycle the fluid.

Certainly, it is best to recycle it and one should be aware of local
requirements.  The point is that one should also not get in a panic if it
gets flushed down the toilet.

See the link

http://www.inchem.org/documents/cicads/cicads/cicad_22.htm#PartNumber:1
which uses these references:

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