Sept 17 (Reuters) - Energy Transfer ( ET ) said a fire

at its natural gas liquid (NGL) pipeline in La Porte, Texas,

which started on Monday, was continuing to burn itself out on

Tuesday morning.

The massive fire on Monday morning knocked out power to

thousands of homes and businesses and prompted a widespread

evacuation of the area, but there were no serious injuries

reported and the pipeline was isolated by midday for residual

product to burn off.

The fire occurred at a valve station on a 20-inch

(50.8-cm) pipeline used to carry NGLs, according to Energy

Transfer ( ET ). NGLs can be used as inputs for petrochemical plants or

burned for space heating and cooking, among other uses.

"Law enforcement agencies have initiated an investigation

into the cause of the incident," Energy Transfer ( ET ) said.

The Texas Railroad Commission, which regulates the state's

oil and gas industry, also said it was investigating what caused

the fire.

About 1,500 CenterPoint Energy ( CNP ) customers were

without power on Tuesday, after initially affecting about 5,000

customers, according to the company's website.

Impacted land owners were being taken care of and have

been provided with lodging at area hotels, Energy Transfer ( ET ) said,

adding that this will continue until evacuation orders are

lifted.