Three harness-racing drivers were seriously injured Tuesday night in a pileup during a race at Rosecroft Raceway, authorities said.

None of the injuries appeared to be life-threatening, according to Mark Brady, spokesman for the Prince George’s County fire and rescue department.

Brady said two of the drivers were initially unconscious and suffered possible head injuries. They were flown to a hospital by helicopter. The third, who suffered undisclosed injuries, was taken by ambulance, Brady said.

Drivers sit behind their horses in two-wheeled carts called sulkies. The pileup, in the night’s fifth race, was apparently touched off by a collision between those in first and second positions. More collisions followed, producing a tangle of arms and legs, wheels and hoofs.

No horses were seriously hurt, officials said.

Rescue vehicles were asked to approach the track with sirens off, to avoid startling the horses.

The Fort Washington track has been in operation for more than 60 years and is located about a mile south of the Capital Beltway near the St. Barnabas Road interchange.