ARCADIA, California — Jason Muñoz looked out at the pristine dirt and turf tracks at Santa Anita Park, bathed in sunshine beneath the sentry-like backdrop of the San Gabriel Mountains, and said: "Sad. So sad."

It was Muñoz's first visit to Santa Anita, on the closing day of the racing season at one of the premier horse racing venues in the country, home to the storied Breeders' Cup. He'd come on Sunday with family and friends "for the experience," he said, but only after he'd done some research on the 30 horses that have died or been put to death at the raceway since late December.

Muñoz likened the magnificent half-ton horses that would round the mile-long dirt track and the slightly shorter turf track that it rings to other world-class athletes, the football and soccer stars who risk crippling injury for the enjoyment of the paying audience.

"They're the ones providing the entertainment," he said. But unlike the human athletes, the horses have no say in the matter.

"If there needs to be reforms, I fully support that," he said.

Those reforms have already started. The track was closed for almost all of March; when it reopened March 29, it did so under new rules: Jockeys had to give up their whips for softer cushion crops, and officials sharply clamped down on the use of medicines, including Lasix, an anti-bleeding and diuretic medication that's used to prevent respiratory bleeding in horses, which can cause fatal pulmonary hemorrhages. The American Veterinary Medical Association reported in 2015 that opponents of Lasix "believe a key motivation is the lift in performance seen in horses administered the powerful diuretic."

But horses kept on dying or suffering fatal injuries.

On June 10, the California Horse Racing Board recommended that Santa Anita suspend the rest of its season. The track's owner, the Stronach Group, refused, and because the racing board doesn't have the authority to close a track on its own, horses entered the gates at Santa Anita again this weekend.

On Saturday, American Currency, a 4-year-old gelding, suffered a leg injury while exercising and was put to death, the racing board said — the fourth horse trained by Jerry Hollendorfer to have died this season.

Later in the day, the Stronach Group banned Hollendorfer, 73, a member of the National Museum of Racing's Hall of Fame, from Santa Anita and its other California tracks. That includes Golden Gate Fields in Berkeley, where he's the all-time leading trainer.

"Whatever reforms were put out there, they were followed closely," Hollendorfer said in an interview Sunday on wsRadio of San Diego. "In our barn, I didn't break any rules or anything like that."

Stronach didn't make executives available for comment Sunday.

The deaths began Dec. 30, when a horse called Psychedelicat — also trained by Hollendorfer — was put down after suffering a fatal injury during a $16,000 claiming race. Twenty-nine more followed in the ensuing 25 weeks.

The Los Angeles County district attorney is investigating. Gov. Gavin Newsom called for racing to be halted until the problem is somehow solved. So has Dianne Feinstein, the state's senior U.S. senator — twice.

Bettors flock to automated wagering machines in the south concourse on Sunday, the final day of the 2018-19 season at Santa Anita Park in Arcadia, California. Alex Johnson / NBC News

That assumes there is a "problem," at least in numerical terms. The 2018-19 season at Santa Anita was certainly unusual — but not because so many horses died or were put to death. It was unusual because, relatively speaking, so few were.

Records of the state racing board indicate that 2018-19 was the safest season at Santa Anita since the 2010-11 program, when Santa Anita installed the mile-long dirt track to replace a synthetic main track.

In addition to the 30 confirmed racing or training deaths since Dec. 30, unconfirmed reports from horse racing opponents tallied two other horses that were put to death specifically following injuries during racing or training from July through November, when there were only 22 racing days. If they're confirmed when official figures are released, that would mean 32 horses died or were euthanized during the July 2017 to June 2018 fiscal year, the reporting period for the state racing board.

During the same period through June of last year, 37 horses suffered fatal injuries while racing or training at Santa Anita, according to racing board records. The year before, 54 died — which was an improvement from the tally of 57 in 2015-16.

It's not clear why this season's death toll began raising alarm bells among officials.

The great majority of horses have died or been put to death after having raced or trained on Santa Anita's dirt track since it was installed. Southern California had an unusually wet winter, with 17.85 inches of rain falling on the Pasadena/Arcadia area in January and February, just before racing was suspended in the first week of March — more than double the historical average for the same period. Excessive rain is strongly correlated with danger to horses on dirt tracks.

"My opinion is the problem is with the bad weather," Hall of Fame trainer Ron McAnally told the horse racing magazine Bloodhorse in March.

Pedestrian traffic is blocked off as a horse is walked out of Santa Anita Park in Arcadia, California, on Sunday, the final day of racing for the 2018-19 season. Alex Johnson / NBC News

Stronach says it is working with independent track surface experts "to ensure the safest racing surfaces possible."

Meanwhile, Jerry Hollendorfer is moving his stable to Los Alamitos Race Course, about 25 miles south of Arcadia, where he's been cleared to race at the meet that begins Saturday because, in the words of Ed Allred, the track's owner and chairman, "we do not feel he should be a scapegoat for a problem which derives from a number of factors."

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In his radio interview Sunday, Hollendorfer said he would be all right. His concern, he said, is with "the folks that are working here and have to go to another location," many of whom are Latino and Hispanic immigrants.

"These people depend on me for their livelihoods," he said.

With calls growing to close Santa Anita Park, Paco Wong said he understands the concern. But he's confident the track will stay open, he said Sunday at the Champions gift kiosk on the south concourse of the track, where he was staffing the cash register one last time before he heads off to the University of California at Santa Barbara in the fall.

"Every year, there's a bunch of horses that die," he said. But "if you shut this place down, there would be hundreds of jobs lost."