Product gas from Underground Coal Gasification was monitored during the Hanna IV UCG test conducted by the Laramie Energy Technology Center. The monitoring was designed to provide both process development and environmental data to define the requirements for product gas clean up prior to end use. During two series of test runs, one in the spring of 1978 and the other in late summer of 1979, the product gas was monitored on a weekly basis for particulate loading and size distribution, trace nitrogen and sulfur components, major components, moisture, alkali metals, and seven trace elements.