BS! The security checks made on contractors and their employees 20 or more years ago didn't let anything slip through the cracks. I was always cleared within a day (probably since i've had an FBI file since I was 5) but the list of employees would take anywhere from 2 weeks to a month prior to starting a job and they were either squeeky clean or no clearance. It's simply a matter of lazy, stupid, and careless government employees and a total relaxation of rules.
You would be AMAZED at who got on board ships 20 years ago. Or did you hear about the Radioman Third Class who got deported as an illegal alien? Seems he had a Top Secret/SPECAT/SIOP clearance to boot.
A man of few words, but they're good ones.