The Santa Anita Racetrack on July 30, 2018 in Arcadia, Los Angeles, California. (James Bernal for KPCC)

After closing down last week following the death of 21 horses in under three months, Santa Anita Park reopened its main, one-mile track on Monday morning for training.

According to a statement on the track's website, the track will be available only to joggers and gallopers, and is still not open for racing.

In a statement released Saturday announcing the park's reopening, trackman Dennis Moore — who has been retained by the park to lead an investigation of the main track — said that "we've been able to do a great deal in terms of amending the soil and inspecting it."

In an interview with KPCC, the park's director of publicity, Mike Willman, did not use the word "death" in reference to the problems the track has been having, and declined to confirm with one hundred percent certainty what was causing so many horses to sustain fatal injuries. He instead noted that the "whole situation is multi-factorial," but is probably, at least in part, a result of the recent heavy rains.

"There is no magic bullet...in terms of findings," he said. "You try and go at it from every which way. That said, it just has to be that the leading indicator with this recent unacceptable spike in issues has been the inordinate amount of rain in a short period of time."

The rain, Willman explained, can cause silt and sand to "leech out of the soil," leaving a disproportionate amount of clay. That, in turn, can cause the soil to become compacted, which can be dangerous to horses who are running on it at top speed.

To test the track, Moore and his team used a machine that simulates the impact of a thoroughbred's forelegs — the limbs that typically take the most trauma during racing and training, said Willman. The team also tested samples of the soil, and used techniques such as harrowing, rototilling and churning to remix the soil.

In February, the park's main track was evaluated and was deemed "one hundred percent ready" for training and racing. At least one horse was fatally injured in the weeks following that announcement.

The track will institute new safety protocols when racing resumes. Those include requiring trainers to apply for permission to engage in high-speed training exercises with horses at least 24 hours in advance, hiring a director of equine welfare and requiring complete transparency with regard to veterinary records.

The park expects to reopen for racing within the next few weeks.