NASHVILLE, Tenn. — Investigators have not yet determined how a Ferris wheel seat flipped over at a Tennessee county fair, sending three children plummeting 30 to 45 feet to the ground. But the accident that left a 6-year-old girl with a traumatic brain injury sharpened the focus Tuesday on how carnival ride operators are regulated.

After a 2014 audit found shortcomings in Tennessee’s regulatory program for rides at fairs and amusement parks, state officials decided to get out of the inspection business altogether. Now, the state relies on private inspectors hired by operators and other states’ regulators to determine whether roller coasters, zip lines and Ferris wheels are safe.

Authorities said the three youngsters fell from the ride at the Greene County Fair in eastern Tennessee on Monday night.

In a follow-up to the audit last year, the agency said Tennessee law does not require the state to hire its own inspectors. Funding for the Amusement Device Unit was requested for the budget year ending in June but was denied.

Lawmakers this year did approve nearly $490,000 to bolster the state’s Amusement Device Unit with five new employees. They are not inspectors but will be assigned to work on permitting and verification of compliance with inspection and insurance requirements. Within two years, those jobs are supposed to be paid for through program fees.

The Ferris wheel at the Greene County Fair was operated by Valdosta, Georgia-based Family Attractions.

Dr. Bracken Burns, director of trauma services for Johnson City Medical Center, said the critically injured 6-year-old was in a seat with her 10-year-old sister and a 16-year-old female, who were both in stable condition. Burns said the 10-year-old suffered injuries to her forearms. He said he couldn’t give out information on injuries that the 16-year-old suffered.