Port operators and freight companies will have to pay up for tightened security checks that will extend full background checks to all workers entering U.S. maritime facilities and vessels by the end of the year, industry sources said on Tuesday. Industry sources say they are concerned over the high enrollment and electronic hardware costs associated with the roll-out of high-security biometric identification cards in the next phase of the Transportation Worker Identification Credential (TWIC) program. Homeland Security will begin to require security screening of all workers with unescorted access to ports at the end of the year, raising the number subject to checks to 850,000 from about 400,000 workers, who were required to be screened in April in the TWIC's first phase.