They were overcome by carbon monoxide gas - believed to be from a faulty boiler at their hotel.

Then he sets about tackling the 'noise, carbon monoxide gas and exasperation caused by the traffic problem in our big towns'.

The 'slapdash, shoddy' repair left carbon monoxide gas leaking out.

Carbon monoxide gas was released from the exhaust pipes of tank engines.

Other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories.