Many catalogs are contaminated by explosions and in SEISAN, explosions can be dealt with in several ways. In the data base, confirmed explosion are marked with E and probable explosions with P. These indicators are mostly put in when the operator first registers the event. However, there is also a possibility to automatically identify events which are probable explosions. This is done with program EXFILTER (section 37). In the data base S-files, there is a special format for recording explosion information (command EXP in EEV). The explosion site there can be assigned a three letter code, which can be used by SELECT to find explosions from specific sites. In this format it is also possible to store the explosion charge and explosion location and origin time separately from the calculated location and origin time. In EEV, the command QUARRYCHECK, will look for known quarries near the epicenter in the S-file.