You have been called to a private residence for reports of several people attending a gathering that are feeling unwell.

[answerhappygod]

You have been called to a private residence for reports of
several people attending a gathering that are feeling unwell. On
arrival, each person is complaining of sudden headache, nausea and
breathing difficulties. On further scene assessment you immediately
identify two (2) people are unconscious in the main lounge with a
gas BBQ located inside.
A) What measures would you employ to safeguard yourself, your
partner and others on scene?