It looks like it's loophole closure time all over again.

Supervisor David Campos is once again proposing legislation to stop employers from pocketing millions of dollars that were supposed to pay for employee health care as part of the city's universal health care law.

The centerpiece of Campos' proposal is a requirement that money employers deposit in savings accounts to reimburse their workers for their health care expenses actually gets used for that. Now, employers may take back the unused portion of the money after two years, and some do.

In 2010, 860 employers put a total of $62.5 million into the accounts, paid out $12.4 million and kept the rest, officials reported.

Campos, who on Tuesday will ask the city attorney to draft this latest legislation, tried to close the loophole in 2011 by preventing employers from taking back money until 18 months after an employee had left the company. But after the Board of Supervisors approved his legislation, Mayor Ed Lee vetoed it amid concerns from businesses that said it would tie up millions of dollars and could force them to lay off workers or possibly close.

A draft report from the Office of Labor Standards Enforcement in July indicated that the situation had only improved somewhat.

The overall reimbursement rate to employees rose from 17 percent in 2011 to 25 percent in 2012, with actual payments jumping from $11.3 million to $26.4 million in 2012.

In 2011, 17 percent of employers who opted for the reimbursement accounts to comply with the city's Health Care Security Ordinance paid out absolutely nothing, the draft report said.

In 2012, after the loophole fix, 12 percent of employers with the accounts reported reimbursing nothing for employee health care, the report said.

With the city's economy humming amid growing frustration about income disparity, Campos may find a better reception at the Board of Supervisors for his legislation this time around and get eight votes to make it veto-proof.

More:

Campos wants stricter rules on S.F. health care accounts