AUSTIN, TEXAS>> Top board leaders of Texas’ embattled power grid operator said today they will resign following outrage over more than 4 million customers losing electricity last week during a deadly winter storm, including many whose frigid homes lacked heat for days in subfreezing temperatures.

The resignations are the first since the crisis began in Texas, and calls for wider firings remain in the aftermath of one of the worst power outages in U.S. history.

All of the four board directors who are stepping down, including Chairwoman Sally Talberg, live outside of Texas, which only intensified criticism of the Electric Reliability Council of Texas. The resignations are effective Wednesday — a day before Texas lawmakers are expected to sharply question grid managers and energy officials about the failures during hearings at the state Capitol.

A fifth board member also resigned, and a candidate for a director position who also does not live in Texas withdrew his name.

The board members acknowledged “concerns about out-of-state board leadership” in a letter to grid members and the state’s Public Utility Commission, which oversees ERCOT. During the crisis, ERCOT officials removed contact information for board members off its website, saying they had become the target of threats.

“Our hearts go out to all Texans who have had to go without electricity, heat, and water during frigid temperatures and continue to face the tragic consequences of this emergency,” the letter read.

The other board members are vice chairman Peter Cramton, Terry Bulger and Raymond Hepper. Talberg lives in Michigan and Bulger lives in Wheaton, Illinois, according to their biographies on ERCOT’s website. Cramton and Hepper spent their careers working outside Texas. The fifth board member leaving is Vanessa Anesetti-Parra.

There are a total of 16 members on ERCOT’s board, which appoints officers who manage the grid manager’s day-to-day operations.

Historic snowfall and single-digit temperatures in Texas last week left millions without power and water for days. The storm was part of any icy blast across the Deep South t hat is blamed for at least 80 deaths.

Republican Gov. Greg Abbott has largely blamed the outages on ERCOT and called for investigations. But the problems were wider than ERCOT, including power plants that were knocked offline by the extreme cold and natural gas producers didn’t protect wellheads from freezing.

“The lack of preparedness and transparency at ERCOT is unacceptable, and I welcome these resignations,” Abbott said in a statement. “The State of Texas will continue to investigate ERCOT and uncover the full picture of what went wrong, and we will ensure that the disastrous events of last week are never repeated.”

ERCOT president Bill Magness has said Texas’ power grid — which is uniquely isolated from the rest of the U.S. — was on the brink of collapse in the early hours of Feb. 15 as power plants froze in the cold and a record demand for electricity to heat home overwhelmed the system. He has defended the outages as a necessity, while Abbott has accused ERCOT of misleading Texas about the readiness of the grid.

After ERCOT removed board members’ information from the website, Magness conceded it was public information in a call last week with reporters but did not describe the nature of the threats.

“It was a security, safety idea,” Magness said.

Cramton, whose page on the professional networking site LinkedIn lists him as living in California, declined comment when contacted Tuesday. The other board members did not immediately respond to requests for comment.