California's Occupational Safety and Health agency is investigating the death Wednesday of a farm laborer in Kern County as another possible heat-related fatality on the job.

Abdon Felix, 42, spent the morning loading boxes of table grapes onto a truck in an Arvin vineyard in heat that rose to 108 degrees, according to the Kern County Coroner's Office.

Felix and a co-worker drove north to put the grapes in cold storage in Delano, and Felix became ill near Bakersfield. His co-worker called 911 to summon help at 2:50 p.m., coroner's officials said. But when emergency workers arrived, they found that Felix was not breathing.

They took him to Delano Regional Medical Center, where staff said Felix's core body temperature was 108 degrees. He died about 4 p.m.

"We are treating this as a heat fatality, and we are investigating it," said Dean Fryer, spokesman for Cal-OSHA in San Francisco.

In response to forecasts of more scorching temperatures this week, Cal-OSHA has issued heat alerts and sent out 17 teams of labor inspectors to monitor conditions at work sites, Fryer said.

Cal-OSHA is already investigating the confirmed heat-stress deaths of one farmworker and an oil worker in May, and a possible third heat-related farmworker death in June.

Final results of an autopsy confirming the cause of Felix's death may not be ready for several weeks.

Sunview Vineyards, the Kern County company that coroner's officials identified as Felix's employer, could not be reached for comment.

Fryer said another field laborer fell ill Wednesday in a different Kern County vineyard. Felipe Martinez, 46, was harvesting table grapes outside Bakersfield. He remained hospitalized at Kern Medical Center on Thursday, Fryer said.

In 2005, a year when 12 workers died from heat stress, California adopted a set of regulations that require employers to draft heat-stress response plans, train all workers and provide water, shade and breaks.

Eight workers died as the result of heat in 2006; one died in 2007.

On Wednesday, the day Felix died, state labor officials announced a joint effort with 15 farm industry organizations to hold seminars on heat-stress prevention around the state this month and in August. The first was Thursday in Fresno.

The state also mailed notices about the seminars to all 1,400 licensed farm labor contractors in California. Officials encourage employers to attend, but it is not mandatory.

"I'm thankful they're doing it, but it's too little, too late," United Farm Workers President Arturo Rodriguez said.

He said the union has reported many violations of water and shade requirements in the fields during heat waves this year, but that the state "can't keep up."

Raudel Felix, Abdon Felix's brother, said Thursday that his brother was in good health and that he had been on the job this season for only three days. He said Abdon lived part of the year in his home state of Zacatecas, Mexico, where his wife returned to live with their three children because one child is asthmatic and the Central Valley air made the condition worse.

Raudel said he suspects his brother's death was due, in part, to the speed with which he had to load boxes.

"The more work they do, the more money they make," Raudel said. "But I think these conditions are not appropriate. The truck wasn't air-conditioned either, and they had to drive a long distance."

The three other deaths that Cal-OSHA is investigating have all occurred since May.

On May 16, farmworker Maria Isavel Vasquez Jimenez, 17, died after collapsing two days earlier in a vineyard east of Stockton during a heat wave. The state revoked the license of Merced Farm Labor, the teenager's employer, because of failure to comply with heat-stress prevention rules.

Also on May 16, 27-year-old oil field worker Julius Askew died after suffering heat stroke while working outside in the Bakersfield area.

The agency is also investigating the June 20 death of Jose Macarena Hernandez, 64, who collapsed in a field near Santa Maria, in Santa Barbara County, during 110-degree heat.

Call The Bee's Susan Ferriss, (916) 321-1267.