1 x dewar liquid nitrogen
Wait 'til they're all asleep - better if they all sleep in the same room - close the door, block up the window as best you can, and pump a load of liquid nitrogen onto the floor of the room. They'll die painlessly in about 20-30 minutes and your client will knock on the door the following morning to find they all 'mysteriously' asphyxiated during the night.
(LongJohnBaldry, Fri 11 Jun 2010, 14:54, 2 replies, latest was 16 years ago)

I like this idea
The application of science to a social problem.
( K2k6 has a proper job these days, Fri 11 Jun 2010, 14:55, Reply)

The only good thing about the seemingly endless health and safety talks
is how many different ways you can learn how to kill somebody.
(LongJohnBaldry, Fri 11 Jun 2010, 14:56, Reply)

how would you kill someone with a slight indentation in the carpet?

( Kitty v1.0 desperately naive, Fri 11 Jun 2010, 15:34, Reply)

It's a win-win all round

(Bicycle Repairman "you're also a bit of a wanker", Fri 11 Jun 2010, 14:57, Reply)

Nitrogen is possibly the most dangerous gas you can have around.
Because the body just doesn't react to it. You should not know such things young person.
( Bartleby A dead man on vacation, Fri 11 Jun 2010, 14:56, Reply)

It's used a lot in food packaging IIRC

(Bicycle Repairman "you're also a bit of a wanker", Fri 11 Jun 2010, 14:57, Reply)

It is
I think I'm right in saying that gaseous nitrogen is less of a problem, say, if you have a leaking cylinder, because it won't expand that much when released. Liquid nitrogen, on the other hand, expands to something like 700 times its volume when it boils, which is why it drives all the oxygen out of the room. And all the while, you don't feel a thing, apparently.
(LongJohnBaldry, Fri 11 Jun 2010, 14:59, Reply)

Depends on how big the leak is
If there's enough escaping, it'll displace the air. Remember a new cylinder is at 230 bar, so will produce 230 times its own volume when it's at 1 atmosphere, or thereabouts.
( K2k6 has a proper job these days, Fri 11 Jun 2010, 15:00, Reply)

In small quantities, and its not like you are inside a bag of crispy salad.
I've seen it used to purge gas pipelines, and they clear the site while it goes on.
( Bartleby A dead man on vacation, Fri 11 Jun 2010, 15:01, Reply)

How can you be sure he's not inside a bag of crispy salad?
He might like it in there.
(LongJohnBaldry, Fri 11 Jun 2010, 15:05, Reply)

So how do frogs sometimes survive in those packs?

( Naked Ape call me Caitlyn, Fri 11 Jun 2010, 15:08, Reply)

Their lungs don't need oxygen
due to all of the Gauloises
( K2k6 has a proper job these days, Fri 11 Jun 2010, 15:10, Reply)

Haw hee haw hee haw!

( Naked Ape call me Caitlyn, Fri 11 Jun 2010, 15:10, Reply)

See below for further farmyard noises

(LongJohnBaldry, Fri 11 Jun 2010, 15:11, Reply)

This is a frenchman laughing

( Naked Ape call me Caitlyn, Fri 11 Jun 2010, 15:14, Reply)

I suspected as much
but written down, it could easily be mistaken for a donkey braying
(LongJohnBaldry, Fri 11 Jun 2010, 15:16, Reply)

That's less to do with the nitrogen itself
and more to do with the hazards of pressurised gas tanks and the original contents of the pipe systems having to be vented/ flared etc.

Crashingly dull post, sorry.
(Oil Slick, Sun 13 Jun 2010, 21:42, Reply)

That's why
you're not allowed to carry liquid nitrogen in a lift, and also why we have oxygen monitors in the cylinder store and N₂(l) store.
( K2k6 has a proper job these days, Fri 11 Jun 2010, 14:58, Reply)

Less mature response:
I NO RITE - BUT IT'S LIKE 78% OF THE ATMOSPHERE AND ROOM TEMPERATURE AND PRESSURE!!!!eleventy-one!!!

ASPHYXIATIONLOLS!!!!!
(LongJohnBaldry, Fri 11 Jun 2010, 15:00, Reply)