Beginning in September 2013, OCLC is systematically adding FAST headings to WorldCat bibliographic records. The records affected will already have LCSH assigned, and the routines will be applied only to records that are attributed as being English-language-of-cataloging.
FAST-enriched WorldCat records will include “OCLCF” in the MARC 040 subfield “d” (ǂd), have one or –- more likely -- several 6xx fields with a second indicator of “7” and subfield “2” (ǂ2) that contains the string, “fast.” Additionally, subfield “zero” (ǂ0) will be present in the machine-process-added FAST headings -- this provides the FAST authority record number.
The processes performing this FAST enrichment work in WorldCat will run as background processes and should not adversely impact system performance. OCLC will initially prioritize the enriching records originally created by the Library of Congress and then will apply the FAST enrichment process to records from other sources. For the initial run, records will be excluded from FAST enrichment until at least six months from date of entry have elapsed.
More detailed information about this enrichment of WorldCat is available here: http://www.oclc.org/en-US/news/announcements/2013/enriching-worldcat-with-fast.html