In reply to xplorer:
What facts?
The simple point is I don't believe you and ask "why" for two reasons.
Why should I trust you, do you have specific knowledge, perhaps you work in a council yard, are a chemist or have qualifications in the area.
But the important why, is why would you add ethylene glycol to road grit. It makes no economic or technical sense. In addition it is a pollutant and as such it's use should be controlled and I find it hard to see how a UK council would spray the stuff about in anything other than very unusual circumstances.
Now if you have EVIDENCE that supports your argument then you should put it up here. Then if the quality of your evidence is greater than mine people will be minded to believe you and ignore me.
Here is some of my evidence, the British Standard BS 3247: 1991 for anti-icing salt for highways makes no allowance for the inclusion of ethelyne-glycol.
How about... Bristol Council (says no anti-freeze in it's grit)
https://twitter.com/BristolCouncil/status/293342153659256832
The environment agency report on de/anti-icing in the UK
http://www.environment-agency.gov.uk/static/documents/Business/PPTI_De_Icer...
DfT standards for winter road treatment... pointing out that salt is effective down to -10. Glycol gets mentioned only once in the annex on severe weather specialist materials.
http://www.dft.gov.uk/ha/standards/nmm_rwsc/docs/nmm_part_5.pdf
So, to recap. Anti-freeze (Ethylene Glycol) poisoning is a real and very nasty way for animals to die. The main reason it is so dangerous is that it has a sweet taste and thus lethal quantities can be ingested before the animal stops consuming it. It is toxic and concentrated, about 100 ml will kill an adult human. (ref www.fscimage.fishersci.com/msds/09400.htm)
Ethylene Glycol is (comparatively) fantastically expensive and un-nessesary in UK conditions making it unlikely to be used in bulk, unless you are de-icing an aeroplane.
Rock Salt is used on UK roads as an anti-icing treatment and in greater concentrations as a de-icer. At most it is about 40g /m^2. It does not have the same issues as E-G in terms of palatability or concentration. Interestingly the L/D 50 is quite low at only about 3000 mg/kg for rats (
http://www.sciencelab.com/msds.php?msdsId=9924972) Actually getting an animal to eat the L/D 50 is much harder for salt than for E-G where pools or containers of the fluid are an issue.