On Sat, 25 Feb 2012 23:05:35 -0500, John
wrote:

You could always get a canary.

John

That only works in Coal Mines.

And I doubt you'll get a Class 1 Group A B C D rating on a Canary - by
the time they complete the testing regimen and the certification
paperwork it would die of old age, and they'd have to get another
chick and start over.

-- Bruce --