Fine, it was a jail, not a prison. the choice of construction materials was to save 600,000 in construction costs.
http://www.sdsheriff.net/library/bf_jails.html
a web search will turn up more references. I found an old article indicating that 11 jailbreaks occured over 7 years, mostly from quick punches through walls. Im almost positive that the building was either closed or turned into a all-female adolecent correctional facility or something.