Supporters of a bill that forces large companies to pay a minimum amount for health benefits planned to use the new data to press lawmakers for a vote on the measure.
Wal-Mart officials and business groups have railed against the proposal, saying it is meant to punish certain businesses and will have no real effect for workers who need help paying their hospital bills.
The report estimates that in 2004, Wal-Mart workers received more than $22.7 million in taxpayer-funded health benefits. More than $12.1 million of that total came from Washington state's coffers.
Democratic lawmakers and union activists scheduled a news conference Tuesday to release the report, which was obtained by The Associated Press through a public records request.
Wal-Mart spokeswoman Jennifer Holder questioned the report's accuracy and said company officials have been denied access to key state data on the subject.
In any case, employment numbers used to generate the cost figures are from 2004, and Wal-Mart has vastly improved its health care benefits since then, Holder said.
"It's an apples and oranges comparison from Wal-Mart in 2004 to Wal-Mart today," she said.
State Senate staffers based the estimates on figures in two earlier confidential reports detailing which employers in Washington had the most workers receiving government health benefits in 2004.
In those reports, Wal-Mart was the leader in workers receiving government health assistance. The world's largest retailer has about 16,000 employees in Washington.
Senate staff members used the earlier reports as a basis for the new cost estimates, figuring that Wal-Mart had 3,180 employees on the state-federal Medicaid program and 456 on the state-funded Basic Health Plan in 2004.
The new report also includes public-health cost estimates for three other large retail or grocery outlets: Safeway, with more than $10.8 million spent on its workers; Fred Meyer, with more than $7 million; and Target, with more than $5.8 million.
Officials computed an average monthly cost to the state of $182 for workers on Washington's Basic Health Plan. Each worker who received Medicaid benefits was assumed to cost the state an average of $291 per month. The report also calculates the federal share for Medicaid clients.
The reports do not attempt to calculate the additional cost of taxpayer health benefits for dependent children of those workers. But the report said costs would increase by 20 percent for each Medicaid-eligible child supported by a worker.
"You have to double, if not more than double, the numbers that we have per year. Just think about what that means," said Robby Stern, a union lobbyist pushing for the health care bills in Olympia.
The bills being considered in Washington this year are part of a push by organized labor in more than 30 states to force minimum health care spending. Washington state's version would require companies with at least 5,000 workers to contribute an amount equal to 9 percent of their payroll to health benefits.
On Tuesday, the Retail Industry Leaders Association, a trade group, sued to challenge a Maryland law designed to pressure Wal-Mart and other large companies to spend at least 8 percent of payroll on health care or contribute the difference to the state Medicaid fund.
Wal-Mart says it has more than 615,000 of its 1.3 million workers are covered by company health plans, and also says it has taken some 160,000 people off the uninsured rolls.
The health insurance bills are SB6356 and HB2517.
