Three multi-vehicle crashes in the southbound lanes of Interstate 95 in a five-hour stretch Sunday, the first in Old Lyme and the other two in Waterford, resulted in a fatality and more than 20 injuries, and backed up the highway for hours.

The crashes taxed state and local police, firefighters and emergency medical personnel and even required both Life Star helicopters to transfer patients from Lawrence + Memorial Hospital. Ambulances were called in from area towns and there was an influx of patients to the hospital, its Pequot Health Center and the Shoreline Medical Center in Westbrook. State police said they believe the backup from the earlier crash played a role in the later ones.

The first crash, which occurred at 4:30 p.m. in Old Lyme between Exits 70 and 71, involved a tour bus and four passenger vehicles. State police said 15 people were transported to the Shoreline Medical Center in Westbrook for treatment of minor injuries. The crash backed up traffic on the highway to Waterford, but the road remained open and traffic slowly moved through the area in one lane. A staging area was set up just off Exit 71 for ambulances responding from several area towns. The Exit 71 on-ramp from Four Mile River Road was closed for a time.

At 7:05 p.m. in the vicinity of Exit 81 in Waterford, one person died and others were seriously injured in a crash involving a tractor-trailer truck and three cars, state police said. The person who died was a passenger in one of the cars. Other victims were transferred to Lawrence + Memorial Hospital, where a Life Star helicopter transferred one person to Yale-New Haven Hospital.

The crash initially closed the highway in both directions, but the northbound lanes were reopened about 9 p.m. Southbound traffic was already backed up because of the earlier crash in Old Lyme and worsened the backup.

At 9:35 p.m. another crash, involving seven vehicles including a tractor trailer, seriously injured more people near Exit 82. Life Star again landed at the hospital. Ambulances from surrounding towns were also needed to assist in transporting patients.

I-95 south remained closed between Exits 81 and 82 for nearly nine hours. The highway reopened at about 6:13 a.m. Monday.

In addition, state police responded Sunday night to several minor crashes on the highway.

t.townsend@theday.com

Twitter: @ConnecticuTess

j.wojtas@theday.com

@joewojtas

Editor's note: An earlier version of this story quoted state police as reporting that the accidents had resulted in two fatalities. The information provided by police later proved to be incorrect.