5 Min Read HOUSTON (Reuters) - Texas oil producers and refiners remained shut for a fifth day on Wednesday after several days of blistering cold, and the governor ordered a ban on natural gas exports from the state to try to speed the restoration of power. Alvin Williams, 66, checks on his smartphone while taking a shelter at Gallery Furniture store which opened its door and transformed into a warming station after winter weather caused electricity blackouts in Houston, Texas, U.S. February 17, 2021. REUTERS/Go Nakamura The cold snap, which has killed at least 21 people and knocked out power to more than 4 million people in Texas, is not expected to let up until this weekend.