Texas intervened in its natural gas industry amid an unprecedented energy crisis by banning producers from shipping the power and heating fuel across state lines.

Texas Governor Greg Abbott said during a media briefing Wednesday that he issued an order forbidding sales to power producers outside of its borders through Feb. 21, forcing them to sell to Texas power generators instead.

Abbott was forced to act as millions of Texans remain without power for a third day amid frigid temperatures, with no clear timeline for restoring service. Harris County, which encompasses Houston, said blackouts in the nation’s fourth-largest city may last two more days.

The crumbling of the state’s gas supplies as arctic temperatures took hold at the start of the week has been one of the driving factors behind the cascade of outages. Abbott said 19,800 megawatts of gas-fired generation remains offline in Texas.