Complex sentence: By the end of the program, the records of all participating schools of nursing had been audited by up to thirty-two field auditors, who were assigned to each (USPHS) district office and covered the schools in that area.
Split into simpler sentences: By the end of the program, the records of all participating schools of nursing had barren audited by field auditors. As many as thirty-two auditors were in the field, assigned to each (USPHS) district office and covered the schools in that area.