July 11 (Reuters) - More than 1.3 million homes and

businesses in Texas remained without power on Thursday, four

days after Hurricane Beryl lashed the state with fierce winds

and heavy flooding, sparking frustration among residents who

were facing extreme heat.

Around 1.1 million of those without power were customers of

CenterPoint Energy ( CNP ), the state's largest provider, data

from PowerOutage.us showed.

Although the utility had restored power to 1.16 million

customers since the storm, it was facing increased scrutiny over

its preparations ahead of Beryl. In a letter to CentrePoint,

Congresswoman Sylvia Garcia called the slow restoration of power

a public health crisis.

CenterPoint said on Wednesday it expected to restore power

to an additional 400,000 customers by Friday and 350,000

customers by Sunday. In total, 2.26 million of is customers lost

power in the storm.

"Crews have identified extensive tree damage across the

company's system. Trees across the Greater Houston area were

particularly vulnerable due to three unusual years of weather,

including significant freezes, drought and heavy rain this past

spring," CenterPoint said in a release.

Temperatures in southeast Texas were expected to be in the

low to mid-90 degrees Fahrenheit (low to mid-32 degrees Celsius)

on Thursday, with heat indices in the 100s, the National Weather

Service said on Thursday.

Damage from Beryl could cost insurers in the United States

roughly $2.7 million, catastrophe modeling company Karen Clark &

Co said on Thursday.

Beryl, which made landfall as a Category-1 storm early

Monday morning, shut major ports along the Gulf Coast and

disrupted some refining and production processes, though many

had resumed normal operations by Thursday.

The Texas Gulf Coast is home to massive oil and gas

processing facilities, as well as export plants and chemical

manufacturers. Texas accounts for 40% of U.S. oil output and 20%

of the country's natural gas production.

Freeport LNG, one of the largest liquefied natural gas

facilities in the United States, was set to restart operations

on Thursday, sources told Reuters earlier this week, after

ramping down production for the storm over the weekend.

Operations at the facility would be limited by the port,

which continued to operate with restrictions.

Chemical maker Olin declared a force majeure for some

product and aromatic shipments after Beryl caused damage to its

Freeport facilities.