Jesse Ceniceros was at the top of his profession as a mechanic for Lockheed Martin (search) when he was injured on the job and fell into California's workers' compensation (search) maze.

Now out of work and hobbled by pain, he may lose tens of thousands of dollars in benefits because of the sweeping changes in the system that were pushed through the Legislature earlier this year by Gov. Arnold Schwarzenegger (search).

The new law, part of a two-year effort by lawmakers to rein-in skyrocketing workers' comp insurance rates, also has delayed or reopened many workers' cases, in large part because of new treatment guidelines that have brought a flood of rejection notices from insurers, critics say.

"Every day we're getting 15 of these rejections or more," says Helen Seagull, a paralegal at a law office in Pomona. "The client calls me and asks me what can I do? Nothing. We can't do a thing."

Among other things, the new law requires physicians to determine the percentage of a worker's permanent disability that is caused by work and the percentage that can be attributed to other factors such as arthritis, osteoporosis (search) and body weight.

Even whether or not a woman has given birth can affect how much benefits injured workers receive under the new law. Earlier this year, a doctor concluded that 2 percent of a hotel maid's abdominal problem was caused by hauling a bed and 98 percent by the fact that she was overweight and had three children.

"It could affect anybody," says Ceniceros, 49.

At the same time the changes in law haven't made a huge dent in the cost of the workers' compensation insurance that most employers are required to buy.

Workers' comp insurance rates have dropped an average 10.38 percent since the changes were enacted last fall and this spring, according to the Department of Insurance. Yet from 2000 to 2003, rates jumped an average 149 percent, the department said.

"I think this is going to go down as one of the biggest insurance company rip-offs of all time," says Sen. Richard Alarcon, a leading Democratic critic of the legislation and an advocate for state regulation of workers' comp rates.

The legislation's supporters say it's too early to tell what the full impact of the new law will be because much of it hasn't taken effect yet.

"I think companies are cutting rates as much as they are able to, given that we haven't seen all the savings from these reforms yet," said Nicole Mahrt, a spokeswoman for the American Insurance Association (search).

Sen. Chuck Poochigian, a Republican who was the lead author of the legislation, said he expects the law to produce great improvements and more rate reductions.

"When all is said and done and we are a year or two down the road and say it's still a crisis and rates have not come down adequately, obviously we are going to look for further ways to bring about a system that isn't harmful to enterprise," he says. "But that assumes facts not in evidence."

Ceniceros said lawmakers shouldn't wait that long to rework what they did this year, and he wants to talk to Schwarzenegger to give him a real-world view of the effect. "I don't know that he realizes with this gung-ho attitude what he has done to injured workers," Ceniceros said.

Ceniceros' problems started in March 1999 when his left knee popped as he climbed into an electric cart. Knee surgery failed to alleviate his pain and favoring the left leg led to problems with his right knee, hips and back, Ceniceros said.

In May, citing the change in law signed by Schwarzenegger, a physician selected by attorneys for Lockheed and Ceniceros blamed half his hip problems on arthritis, although the doctor said the workplace injury accelerated the condition.

The previous interpretation was that the work-related injury was the sole cause of the disability if the employee had no symptoms of a disabling medical condition, said Mark Gerlach, a consultant for the California Applicant Attorneys Association (search), a group of lawyers who represent injured workers.

Ceniceros says he had no indication he had arthritis before he was injured, although he had diabetes. If the doctor's opinion stands, it could cost Ceniceros about $70,000 to $80,000 in permanent disability pay plus pension benefits that could total another $20,000, said his attorney, Scott Rubel.

Willie Washington, a lobbyist for the California Manufacturers & Technology Association (search), said it's not fair to force employers to pay for conditions that are a natural part of aging.

"The point here is we will pay for the injury but we're not willing to pay for the arthritis you have, unless they can show specially that work itself contributed to the arthritic condition," he said.