Hazardous Mataterial - Recognizing and Identifying the Hazards No. 1 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 3 of 20 3.  What is the single most critical factor at the haz mat incident? p. 178 Choices: Concentration of the contaminant in the air Area affected by the spill Time of day the contamination occurs Quantity of material that has been spilled