Dirt flying as horses race around the track. Fans cheering as their favorite thunders down the stretch, hooves pounding toward the finish line.
That sight and sound has disappeared from some North American racetracks that have replaced traditional dirt with a synthetic surface made of wax-coated sand, fibers and recycled rubber.
It mutes hoofbeats and limits whatever kickback might fly in the faces of trailing horses.
From owners to trainers to jockeys to bettors, the debate is vigorous on whether synthetic surfaces are a potential answer to creating safer training and racing conditions.
The deaths of 12 horses at Churchill Downs, including two on Kentucky Derby day, in the last month have reignited public outcry about what horse racing is doing to prevent catastrophic injuries.
Investigations of the Churchill deaths are underway, including necropsies on the horses and probes of the track's dirt surface.
Synthetic surfaces, known by such trademarked names as Tapeta and Polytrack, are gaining traction in some major racing locales.
Gulfstream Park in Florida added Tapeta in 2021 to go with its dirt and grass courses. Woodbine near Toronto switched from dirt to Polytrack and then to Tapeta in 2016.
In 2015, Turfway Park near Cincinnati was the first track in North America to install Polytrack and five years later replaced it with Tapeta. Tiny Presque Isle Downs near Erie, Pa., has a Tapeta track.
Statistics from The Jockey Club's Equine Injury Database show the surface with the fewest deaths per 1,000 horses is synthetic.
From 2009-2022, there were 534 fatalities on synthetic from 482,169 starts or 1.11 per 1,000 starts. During that same period, there were 6,036 fatalities on dirt from 3,242,505 starts or 1.86 per 1,000 starts. And on grass, there were 1,032 fatalities from 728,445 starts or 1.41 per 1,000 starts.
The overall rate of fatal injury in 2022 was 1.25 deaths per 1,000 starts, down from 1.39 the year before. It's the fourth consecutive year the rate has decreased, according to the EID, and the first time the rate has been below 1.3 deaths per 1,000 since the database began in 2009.
"In my opinion, synthetic is safer," said veteran trainer Mark Casse, who estimates he starts about 1,200 horses a year on dirt, grass and synthetic in the U.S. and Canada.
It hasn't taken hold everywhere, however.
California racing officials mandated a switch from dirt to synthetics in 2007. Santa Anita, now-defunct Hollywood Park and Del Mar north of San Diego spent millions tearing out their dirt tracks in what proved to be a failed experiment.
Golden Gate Fields in the San Francisco Bay area is the only California track still racing on synthetic. Eight horses have died at that track this year -- three involved musculoskeletal issues; the others had varied reasons.
"If they didn't have so many issues early on in California, we'd all probably be racing on synthetic tracks," said Casse, citing the initial steep learning curve involved in installing and maintaining such surfaces.
Drainage problems cost Santa Anita racing days and the subsequent installation of another brand of synthetic failed to perform adequately under extreme temperatures. Heavy usage also wore down the materials quickly, and more watering was often needed to maintain the correct consistency.
"I think there were a lot of mistakes, but we're a a lot smarter now," Casse said.
Dirt still rules in Louisville, Kentucky; Baltimore and New York, where the Belmont Stakes will be run June 10 to conclude the Triple Crown.
But change is afoot.
In March, the New York Racing Association announced plans to install a 1-mile synthetic oval at Belmont Park. It will complement the existing 1 1/2-mile main dirt track and two grass courses when it's completed next spring.
"That's exciting," Casse said. "It's a huge step."
Said Glen Kozak, NYRA senior vice president of operations and capital projects, "The new track represents an investment in the future of Belmont Park that will enhance equine safety, support field size during inclement weather and provide horsemen with another year-round training option."