John Marquez, who grew up in a farmworker family, knows how hot the fields can get.
He knows as well that drinking plenty of water and resting in the shade can keep a worker from being overcome by heat.
"It's common sense, but you don't realize it until it hits you," said Marquez, a Fresno-based consultant to farm labor contractors in the San Joaquin Valley and on the central coast.
He was among about 50 people who attended a seminar Wednesday in Modesto on state rules for protecting workers from heat.
It was one of nearly 40 such events being held this year by the California Division of Occupational Safety and Health and other sponsors.
The rules were tightened in 2006 in response to the deaths of several farmworkers around the state the year before. The rules also apply to people in construction, landscaping and other outdoor jobs.
"The sun has always been out there, but sometimes we forget about it and we don't realize what it does," said George Robinette, a Stockton-based loss control representative with the State Compensation Insurance Fund, co- sponsor of the Modesto seminar. Robinette said workers can be overcome even when temperatures are in the 80s, or when they are not doing strenuous tasks.
The rules require employers to provide each worker with at least one quart of drinking water per hour. They must get breaks of at least five minutes if they are overcome by heat.
"If someone is feeling a little woozy, a little faint, and they need a rest, they can go rest in the shade," Robinette said.
The conditions can range from heat exhaustion, which brings fatigue and nausea, to heatstroke, which can kill if not treated quickly.
Robinette said some job sites, such as roads where asphalt is being laid, are especially dangerous because they radiate heat from the sun.
He said supervisors must assure workers are "acclimated" to heat: Workers tend to do better in midsummer than during an early heat wave, such as the one this week.
Marquez said the prevention message needs to get to farmworkers who are paid by how much of a crop they bring in, rather than an hourly wage.
"A lot of these people that are working a piece rate, they push themselves, they push themselves, they push themselves," he said. "They don't want to take a break."
The rules in general are not burdensome to growers, said Wayne Zipser, executive manager of the Stanislaus County Farm Bureau.
"I just think we need to be conscious of the fact that it gets hot out there," said Zip-ser, who was not at the seminar.
He did question a few details, such as a claim that almond trees don't provide full shade, and how a tractor driver can store drinking water.
The United Farm Workers has redoubled its efforts on heat concerns since Maria Isabel Vasquez Jimenez, 17, died last year after working in a vineyard near Farmington.
In a statement last month, the union said seminars for employers are not enough. It called for increased enforcement of the rules and criminal prosecution of violators.
"The evidence points to neglect, not ignorance, as the cause of farmworker deaths," the statement said.
Bee staff writer John Holland can be reached at email@example.com or 578-2385.