The union representing California grocery clerks is urging an end to a work stoppage that has put 70,000 workers on the picket line. The four-month dispute is over the rising cost of health care benefits.

The issue sparked a strike against one grocery chain and led two others to lock their workers out until the dispute is settled. The three companies, which operate most large California supermarkets, are demanding that workers pay a bigger share of the cost of their medical insurance. The strike and lockout have cost the companies millions of dollars in profit, and cost the workers millions of dollars in wages.

Officials of the United Food and Commercial Workers union want to put the case to a neutral arbitrator, who would have the power to impose a settlement. The companies rejected the offer for binding arbitration. Contract negotiations broke off in December, and the three companies, in a joint statement, ask that they resume.

The supermarket chains want workers to help offset health insurance costs that are rising more than 10 percent a year. The companies also want a two-level system that would offer fewer benefits to new workers.

Local union president Rick Icaza says the higher cost of health insurance would put it out the reach of many of his members. And he says a loss by the union would set a national precedent.

"If the employers prevail in what they want to do, every worker in the nation will be adversely impacted by the fact that they will be taking away health care for all workers, as far as we're concerned," he said.

The companies have said they can no longer compete with discount chains like Wal-Mart, which offer fewer benefits to their workers.

Civil rights leader Jesse Jackson, who came to support the clerks, says the reduction of benefits by discount super-chains threatens the country. "We must start the Wal-Mart-ization of our economy. It will not stop here," he said.

The rising cost of health care has become an issue in one U.S. industry after another. It sparked a recent transit strike that stopped Los Angeles buses for more than one month.

Health care is also an issue in the U.S. presidential election. In December, President Bush signed into law an overhaul of the Medicare system for the elderly and disabled, providing added benefits for prescription medicines. Democratic critics say the bill doesn't do enough to curb rising medical costs, or provide coverage for more than 40 million uninsured Americans.