Since the law was adopted, however, 11 farmworkers have died in possible heat stroke deaths, eight of them confirmed. That's nearly twice the number of such deaths in the nearly three years before the laws were passed, and five of the deaths occurred this year alone.
An Associated Press investigation found that an understaffed labor agency in the nation's biggest agricultural state fails to consistently hold farms and labor contractors accountable for heat deaths or ensure they pay for violations and improve conditions in one of the most brutal jobs in America.
One recent high-profile death of a pregnant, teenage vineyard worker led Cal-OSHA - the state Division of Occupational Safety and Health - to issue a record fine of more than $262,000. But the fines often drop when appealed and have averaged less than $10,000 in other heat-related deaths. In one case, it ended up at just $250.
Currently, 210 state inspectors look for heat-related violations and other safety hazards at farms and all other kinds of work sites. But with just one inspector for every roughly 90,000 workers in California, the gaps are evident.
One day last month in Raisin City, about 20 miles southwest of Fresno, the owner of a cherry-tomato farm was fined $3,365 for violations that included offering no first aid and nothing to drink except a jug of foul, undrinkable water. But about 20 miles away in Kingsburg that same day, Ramiro Carrillo died after hand-picking nectarines in the 112-degree sun; he had gone home after apparently telling co-workers he felt sick.
"Why did no one run over to help him in an emergency? Maybe his life could have been saved," asked his grieving sister Natividad, who said she also fainted from heat stroke this year after pruning bushes at a San Joaquin Valley nursery. "People's lives are being lost but sometimes I wonder if anyone cares if another Mexican immigrant dies."
Only firefighters suffer from heat stroke at a higher rate than farmworkers, and no occupation sees more deaths from it.
Cal-OSHA officials say they've been aggressive in trying to prevent heat-related workplace deaths. They note that California has a lower rate of heat-related deaths among farmworkers than other states, including North Carolina, where seven farmworkers died from 2003 to 2006, and Florida, where four died in that time span.
Cal-OSHA Chief Len Welsh said inspectors have stepped up sweeps through the fields this summer in anticipation of a deadly string of heat waves, and set each penalty according to strict formulas.
"You see people crouching underneath tractors when you go out in the fields. We think workers should be able to rest with dignity," Welsh said. "If somebody doesn't have shade up and available for workers this summer, they're going to get a whooping."
Violations are common: The agency conducted 1,018 heat inspections last year and found that 490 companies had violated heat illness laws.
The AP review, however, found that authorities have yet to collect fines in several heat death cases. In four of the cases, the agency's appeals board cut the fines by around half, or sometimes more.
One central California farm paid the state just $250 after a 38-year-old man died harvesting lettuce seeds, following the farm's appeal of a $13,500 penalty, according to records.
Welsh said his office has no authority over the appeals process, and said the department that collects fines from employers has been slow to respond.
"Collections has been a problem historically and we need to fix it. I can't sugar coat it," he said. "People have been dying all along every year for decades, and now that we're finally focusing on it we're finding all these heat fatalities. We're doing all we can with the very limited resources we have."
The AP's review of state and federal data reveals Cal-OSHA's record-keeping is so poor officials have had trouble tallying how many people have died. Different data sets provided to the AP showed anywhere from six to 19 heat-related farmworker deaths confirmed or under investigation between 2005 and 2008, including several before the new rules took effect. Welsh acknowledged the agency needs to improve its record-keeping.
The highest-profile heat death in the fields has been that of Maria Isabel Vasquez Jimenez, a pregnant 17-year-old who died May 14. Authorities believe she collapsed because her supervisors denied her access to shade and water as she pruned white wine grapes for more than nine hours in nearly triple-digit heat.
Cal-OSHA recently hit the contractor in that case, Merced Farm Labor, with a $262,700 fine, the highest penalty the agency has ever issued to an agricultural firm, and state authorities now want to revoke the company's license. Merced has appealed the fine.
Outside of that incident, however, companies were fined an average of just $9,945 for farmworkers who died from 2005 to 2008, even in the case of "serious" violations. Merced's fine was higher because state officials concluded that its violations were deliberate.
State Assemblyman Sandre Swanson, an Alameda Democrat who sponsored a failed bill to give Cal-OSHA stronger enforcement powers, said the system is broken because employers don't have to fix hazards while the state's citations are being challenged.
"Unscrupulous employers can game the system by filing frivolous appeals," Swanson said. "We cannot expect our workers to endure a lengthy series of appeals, especially when people have actually died from these conditions."
Bryan Little, director of labor affairs with the California Farm Bureau Federation, said most growers strictly follow the rules and make a conscious effort to teach foremen how to watch for the signs of heat stroke.
Heat deaths are a nationwide problem at work places including farms, construction sites and oil derricks. At least 34 farmworkers in the U.S. have died of possible heat stroke between 2003 and 2008; according to state and federal data, 17 of those deaths were in California.
California is one of 21 states that has its own worker safety program.
Before the current law took effect, there were no specific employer rules regarding heat illness although they were required to have an injury and illness prevention program. A string of 10 deaths - four of them farmworkers - in a two-month period in 2005 prompted regulators to toughen the rules.
California Farm Bureau's Little said giving the agency still more oversight won't keep people from dying.
"Is the purpose of Cal-OSHA to induce compliance and protect workers, or is the purpose to collect fine money from employers?" Little said. "Encouraging employers to settle gets the hazards abated more quickly, and gets employees protected more quickly."
Advocates argue that lowering penalties - even when a worker has died - renders the regulations toothless.
"I completely understand that Cal-OSHA is overworked and understaffed, but what's offensive is that the agency is reducing fines with no justification," said Michael Marsh, an attorney with the nonprofit California Rural Legal Assistance. "In some cases, companies are paying pennies on the dollar from the original fine imposed."