The Cobb County School District will remove the controversial ultraviolet sanitizing lights installed in classrooms to fight the spread of COVID-19 after they malfunctioned last month, it announced Wednesday in a letter to parents.

The decision to remove the lights comes 9 days after lights in two offices at Argyle Elementary School malfunctioned, coming on while students and teachers were in the building. It also follows intense scrutiny by some parents after the Board of Education in December voted to spend up to $12 million to install the lights, as well as hand-rinsing machines, at all of Cobb’s 67 elementary schools.

The lights, which are installed in ceilings, are designed to activate during the overnight hours to kill harmful microbes on surfaces — when no one is in the building.

According to a letter sent to parents, students and teachers at Argyle, Baker, Belmont Hills, Bryant, City View, Ford, Murdock, Nicholson, Riverside, Smyrna and Sope Creek elementary schools, where the lights are installed, the malfunction was caused by a failure in the timing hardware and motion detectors.

The lights came on in two offices during the school day “when they should not have been able to operate,” the school district said.

“Although no students were present in either office, one adult was present, suggesting the motion detector and timing hardware failed,” the district said. “In addition, other UV lights flickered on and off throughout the building in what appeared to be attempts to turn on.”

According to information obtained by The Atlanta Journal-Constitution in an Open Records request, Cobb schools has so far paid ProTek Life $768,634 to install the lights. It’s not clear how many of the lights have been installed at the schools.

Following the malfunction, the district paused the use of the lights and investigated. It was later determined the product did not function as outlined in the district’s request for proposal for the technology, Cobb schools said.

The district has told ProTek Life, based in Kennesaw, that it will stop using the lights and will require the company to remove the technology from its schools. It’s also requesting ProTek to refund the money it spent on the purchase.

“We acknowledge the success of the ProTek Life product during the proof-of-concept period and ProTek Life’s belief that this is a single failure of their product,” the district said. “We also appreciate it does not appear any employees or students were harmed by this failure. However, we do not believe even a single failure to meet the high health and safety standard established in our RFP process is acceptable.”

School officials have never directly answered questions from parents about the health risk posed by exposure to the UV lights.

Parents who expressed concerns about the purchase said Superintendent Chris Ragsdale did not provide any data that proves the equipment is worth the price tag. Parents argued that the money would be better spent on items and processes proven to help stop the spread of COVID-19. They also said no information was provided to show the products were any more effective than soap and water in the fight against COVID.

Cobb school board member Charisse Davis, who voted against the December purchase, said she’s glad the district is removing “potentially harmful products from our schools.”

“Products that can potentially harm students and staff should undergo more scrutiny, not less,” she said.

Board Chairman Randy Scamihorn, who voted in favor of purchasing the lights, said it was unfortunate that the company was unable to fulfil the obligation spelled out in its contract. He also said the district’s decision to remove the lights is proof that the school system will do what is necessary to keep students and staff safe.

“Our students and faculty and staff always come first, no matter what,” he said.