6 ms·

They have fume extractor fans in the tunnels. If they aren't on, CO poisoning for everyone.

• ghshephard 14y ago
  One would hope that the "fail safe" scenario for fume extractor fans would be "Blow at full speed"
  • redthrowaway 14y ago
    Or, indeed, that they wouldn't be linked to the traffic light system in the first place.