Hazardous Mataterial - Recognizing and Identifying the Hazards No. 2 Questions taken from Jones & Bartlett Fundamentals of Fire Fighter Skills (3rd Edition) Progress Indicator: Question 3 of 20 3.  The required minimum number and type of operational gas detectors that must be available to a MNM mine rescue team is? Choices: 2 equipped with CO, CO2, O2 and LEL 4 equipped with CO, NO2, O2 and LEL 2 electronic detectors and 2 Dragers equipped with CO, NO, O2 and Methane 4 detectors capable of testing for each gas that may be encountered