In my personal assessment (with severely limited information), the two truck-mounted processing units were used for a clandestine biological program at some point or another. In my observation and extrapolation (seeing them on TV and reading publicly disclosed analysis) they were abandoned quite some while ago. I have little doubt that they will be used to bolster the WMD reports, in any event, which Blair stated will be released at some future time. Otherwise, an article perhaps of interest:
No germ agents in Iraqi mobile labs
Painstaking analysis has failed to find any trace of outlawed germ warfare agents in two truck-mounted biological processing plants that U.S. forces discovered in Iraq...