This paper will describe the design of two infrared optical pyrometers used to study dust explosions. One is a six-wavelength pyrometer which can measure both dust particle temperature and gas temperature by observing continuum and gas band emission in the 1 to 5µm infrared region using PbSe detectors. The second pyrometer measures particle continuum emission in the 0.8 to 1.0 µm region of the near infrared using Si detectors. Temperature data are presented for both laboratory and full-scale mine explosions.