How dangerous is a chlorine spill?

A train derailed about 5 miles from my apartment and it apparently in contains chlorine and other hazardous materials. I was wondering how bad it would be if anything leaked.

Read my cite more carefully and thankfully the “hazardous containers” are empty. Other cites say different but we will see.

Hopefully no gas, then, but -

Chlorine gas can kill you. The chances of a derailment 5 miles away being able to affect you would likely depend on weather and terrain conditions between you and the crash site.

To be fair, your link only says that cars (sometimes contain hazardous material, but empty in this case) have been derailed. No mention of chlorine. Maybe it was edited after your post.

Chlorine is nasty stuff. There was a train collision in South Carolina in 2005 where 60 tons of chlorine gas were released.

Chlorine was used as a chemical warfare agent in WW1, before they switched to more effective phosgene or phosgene/chlorine mix.

So year, pretty nasty stuff.

TL;DR: it doesn’t take much chlorine at all to severely injure you, and it doesn’t take much more than that to kill you.

The Emergency Response Guidebook recommends an evacuation distance of at least 5 miles downwind from a large chlorine spill at night.