One person was airlifted to a hospital and another taken by ambulance with serious injuries after a boat ran aground at Lake Austin, in Texas, Sunday, authorities said.

According to the Austin-Travis County Emergency Medical Services (ATCEMS), a boat carrying seven people ran aground on Sunday evening. In addition to the two transported with serious injuries, two others were described as having “potentially serious injuries,” and a teen listed as “missing/unable to locate,” the ATCEMS said on X (formally known as Twitter). Two patients also refused transport to local hospitals.

Authorities declared the incident a Level-5 mass casualty.

The incident took place in a remote area and required the use of jet skis to move those who were injured. The responders are in “recovery mode,” according ATCEMS.

This is a developing story.

Marilyn Heck contributed to this story.