WASHINGTON (AP) — The House Oversight Committee is investigating the agency that operates the Texas power grid, seeking information and documents about the lack of preparation for the recent winter storm that caused millions of power outages and dozens of deaths across the state.

Rep. Ro Khanna, a California Democrat who chairs an environment subcommittee, sent a letter to the Electric Reliability Council of Texas, saying he is concerned that the loss of electric service — “and the resulting human suffering, deaths and economic costs” — will happen again unless ERCOT and the state of Texas adequately prepare for a predicted increase in extreme weather events.

Severe winter storms in Texas “have occurred repeatedly over decades, and ERCOT has been unprepared for them,” Khanna wrote in a letter to ERCOT CEO Bill Magness. The group’s own consultant has predicted that severe winter weather events will continue to occur every decade, yet ERCOT and state officials have done little to prepare for them or build appropriate infrastructure, Khanna said.

Magness was fired Wednesday amid growing calls for his ouster following the deadly storms, but will stay on for two months to “work with state leaders and regulators on potential reforms to ERCOT,” the organization said in a statement.

“The failures of ERCOT and the state of Texas were costly,” Khanna wrote. At least 49 Texans have died, and more than 4.5 million people experienced power outages

“Homeowners, renters and businesses face steep expenses to fix damage from frozen and burst pipes, with the Texas Insurance Council estimating that claims could be more than $20 billion,” Khanna wrote.