Jose Alatorre was overcome by fumes from the fetid stew as he tried to fix a pump at the bottom of a 30-foot concrete shaft. His partner died trying to save him.

Both men were full-time workers but, according to prosecutors, were given no safety training and no safety equipment to deal with the predictably hazardous air.

The deaths received a burst of attention in early 2001, but 18 months later in the same small town, a third Mexican-born worker died in the same way at another dairy.

Sobering statistics

The AP's investigation focused on 1996 through 2002, the most recent set of worker death data from the U.S. Bureau of Labor Statistics. Those were years when the economic boom coaxed about 1 million Mexicans beyond the border states, according to government estimates.

During those years, the analysis showed, Mexicans were increasingly more likely to die on the job than U.S. workers of any race.

The annual death rate for Mexicans increased to the point that about 1 in 16,000 workers died. Meanwhile, for the average U.S.-born worker, the rate steadily decreased to about 1 in 28,000.

Mexicans now represent about 1 in 24 workers in the United States, but about 1 in 14 workplace deaths.

Workplace fatalities had distinct regional patterns:

CALIFORNIA AND TEXAS: These states, where generations of Mexicans have developed strong support networks, still rank atop the annual number of Mexican worker deaths — but their numbers have steadied or fallen recently. Though low relative to other states, the death rate for Mexican workers in California is still greater than the average for U.S.-born workers.

SOUTH: In the bloc of states from Louisiana to Maryland, the Mexican death rate averaged about 1 in 6,200 workers — four times that of native-born workers. Total deaths more than tripled from 27 in 1996 to 94 in 2002 in the South (excluding Texas), where some states saw Mexican populations triple to more than 100,000 workers.

WEST: Outside California, deaths in Western states increased from 41 to 58, and death rates hovered above the national average. Colorado and Washington stood out with consistently high rates.

MIDWEST: The number of Mexicans killed annually doubled between 1996 and 2002, from 19 to 38; death rates were slightly above the national average for Mexicans.

NORTHEAST: The region has the fewest Mexicans, but death rates still far exceeded American worker averages. Total annual deaths rose from eight to 17.