Salvage and Overhaul No. 1 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 2 of 20 2.  The degree to which a toxic gas will affect you depends on three factors: how concentrated the gas is how toxic the gas is and _____________. Choices: the Threshold Limit Value of the gas. whether the gas has an IDLH limit. how well the gas interacts with oxygen. how long you are exposed to the gas.