The University has an air permit for the steam-generating boilers in the Central Plant. We also claim several types of general air emission sources that are allowed by the TCEQ without the need for a specific permit. These are called permits by rule (PBRs) and the University's most common PBR emission source is emergency power generators found throughout the campus. EHL tracks the use of emergency generators on a 12 month rolling period. The emergency electric generators are operated under permit by rule authorization 106.511. Other permits such as bench-scale analytical work covers much of the work performed in research labs.