Effects of breathing small amounts of natural gas for extended periods?

[Dave Plowman (News)]

I had a smell which I thought was gas. Turned out to be a dead rat...

[Mike D]

That's interesting... my cat *has* been known to bring dead mice into the house. All I need now is an electronic dead-mouse finder! It took me ages to find the last one. It eventually turned up in a coat pocket, of all places. I still can't imagine how it got there. Funny how mice keep cropping up in this thread. First 'ha ha mice', now 'dead mice'...

Mike D

[Mike D]

It takes so long, you may as will light up a cigarette while waiting...

Mike

[Pete Cross]

My wife rang me at work a few week back saying there's a strong smell of gas in my son's bedroom. To be on the safe side I bought a CO monitor/alarm on the way home as the only source I could imagine was the boiler flue about

10ft from his window maybe getting sucked in through an airbrick or ? I got home and it did smell like gas so I 'paid a visit' before putting batteries in the monitor, the smell of gas was increased by me letting out the coffee I'd had at work earlier! she'd put a load of bleach in the loo! it really did smell like gas..... the monitor has been all over the house btw and it reads 0ppm everywhere even on top of the boiler....

Also, interestingly, to test the meter it says to use a joss stick! close up it should read 10ppm! wonder how unhealthy a handfull in a room would be ?

Pete

[Paul C]

Methane is odourless so they add a 'smelly'. I think the additive is Ethyl Mercaptan (Ethanethiol) and its a ridiculously low concentration as that stuff is so smelly. When I worked in a lab years ago, someone threw 5 millilitres down a sink and the building had to be evacuated due to the nauseous affect of the pong. Neighbours around the site were phoning British Gas reporting smell of gas.

Paul

[Andrew Gabriel]

Imperial College in the early 1980's, or did someone else do that too?

[Aidan Karley]

MOST natural gases contain significant ethane mixed with the methane, though the proportions do vary. (Exception - natural gas produced by the biological decomposition of organic matter can be essentially pure methane. But practical gas sources in Western Europe are the result of natural catalytic cracking, so produce a spread of output compounds depending on the feedstock and the conditions of cracking.) Ethane is readily available onshore (and offshore in many cases, from co-processing of other parts of the field), so mixing to produce the desired blend for the consumer network is not a major problem. What happens with re-gasifying LNG (at places like Milford Haven), I don't know. I could see real arguments going both ways for keeping the gases pure, or for keeping the gases blended.