Company officials, including Belinda Stronach, the chairwoman and president, insisted that safety had always been the top priority, though she has never hidden her desire to make Santa Anita as profitable as it can be — profitable enough to resist the temptation to sell the track to developers.

The push to boost revenues required a relentless racing schedule, the people said, despite unusually rainy and cold weather in Southern California that might have made the track less safe. Of the 30 deaths, 11 occurred during training, when horses were presumably not going full speed, suggesting problems with the track’s surface.

And to increase betting, track managers held more races with bigger fields, which put intense pressure on trainers to race horses that may not have had enough rest or been in the proper condition, owners and trainers said.

The track tolerated trainers who had been cited for using performance-affecting drugs, records showed. Experts have long considered drugs a leading cause of horse deaths. Not only do they dull pain and mask injuries, letting at-risk horses run when they should not, but they make horses unnaturally stronger and faster, increasing stress on their limbs.

“It was the perfect storm of terrible weather, a dearth of horses — many of them who shouldn’t have been running here,” said Rick Arthur, the equine medical director for the California Horse Racing Board. “There was a big push to fill races, and some people haven’t been as cautious as they should have, on both sides.”

State regulators are investigating the rash of deaths, as is the Los Angeles County district attorney’s office.