originally posted to FA a few hours ago -
- no apologies if I missed anything changing from FA's standard to Weasyl's goofy system
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In case you haven't heard yet, at about a quarter after midnight Saturday night/Sunday morning, some arsehole took a bottle of what was probably swimming pool hypochlorate, (what the news has been referring to as "powdered chlorine"), and smashed it in the stairwell on the ninth floor of the Hyatt Regency hotel where MFF was going on. Somebody smelled it and reported it to the hotel; the hotel told the fire department and the fire department called in a hazmat team. The hotel was evacuated between a quarter to one and twenty after four in the morning. Nineteen people were taken to hospital with symptoms related to chlorine gas exposure, (I don't know as I write how many of them were Furries and how many were hotel staff or other hotel guests.)

Most of the evacuees were there for MFF. However, the Hyatt Regency was also hosting a dog show for the Skokie Valley Kennel Club. So we might have been attacked by trolls, but it might have been PETA attacking the pet owners. (Or something else.) Police are still investigating.

Collected below are some news reports of the incident. I'm posting The Cardinal's report first because it was the most helpful.
http://www.arlingtoncardinal.com/2014/12/glass-jar-with-white-substance-strong-chlorine-smell-causes-firefighter-ems-hazmat-response-evacuation-at-hyatt-regency-rosemont/?utm_medium=twitte
http://www.bt.cdc.gov/agent/chlorine/basics/facts.asp -- CDC brief on the effects of chlorine gas
http://abc7chicago.com/news/furfest-evacuated-by-intentional-chemical-leak/425617/ -- ABC7
http://abc13.com/news/photos-furfest-evacuated-after-chemical-leak/425633/[/url] -- ABC13
http://www.nbcchicago.com/news/local/Intentional-Chemical-Leak-at-Hyatt-Regency-285008481.html-- NBC5
http://www.chicagotribune.com/news/local/breaking/chi-19-hospitalized-thousands-evacuated-in-gas-leak-at-rosemont-hotel-20141207-story.html-- Chicago Tribune
http://www.rawstory.com/rs/2014/12/19-hospitalized-after-intentional-release-of-chlorine-gas-at-chicago-furry-animal-character-confab/ -- Raw Story

And here are a few videos.
WGN News -- https://www.youtube.com/watch?v=Pv3lyMt0-3w

Associated Press -- https://www.youtube.com/watch?v=kG3H0oNW46c
(No AP, Anthrocon is not the same thing as Midwest FurFest.)

livecast by Axio Wolf -- https://www.youtube.com/watch?v=TUEqBCjhGSg

Axio Wolf Pt. 2 -- https://www.youtube.com/watch?v=i04y2heuM2g

https://www.youtube.com/results?search_query=axio+wolf-- Axio wolf's channel

Pyat Pt.1 --https://www.youtube.com/watch?v=wcdI4v49QRE

Pyat Pt.2 -- https://www.youtube.com/watch?v=v5ifgC4vVHQ

...assault (19 counts), administering a noxious agent, reckless endangerment, criminal vandalism... That should do for a start.
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UPDATE -- According to Fury Fire, (who worked at MFF2014), only 4-5 of the 19 Furries taken to hospital were effected by chlorine gas. The rest were fursuiters suffering from dehydration because they couldn't get water during the evacuation, (or other reasons.)
http://www.furaffinity.net/journal/6326463/#cid:43412815

An additional thought; a disgruntled employee would have had access to the hotel's supply of hypochlorate, assuming it has a pool. 8/DEC/2014
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UPDATE -- Prompted by a question to the duplicate of this journal on SF, I called the Hyatt Regency O'Hare and asked if they have a pool. They don't. later 8/DEC/2014