Shell Plc on Monday said the reignited fire at its chemicals facility in the Houston suburb of Deer Park, Texas, was extinguished Sunday night but intermittent flaring could continue.

The fire, which initially ignited on Friday in an explosion in an olefins unit, was extinguished for a few hours on Saturday morning before reigniting later.

"We are using less water to manage the hot spots and have closed the valve eliminating discharge to the Houston Ship Channel," the company said in a statement.

No injuries were reported from the fire. Nine people were evaluated and released at local hospitals on Friday for possible chemical exposure.

"Air monitoring is ongoing and has not detected any harmful levels of chemicals affecting neighboring communities. There is no danger to the nearby community," Shell said, adding the cause of the fire was under investigation.

Jennifer Hadayia, executive director of Air Alliance Houston, said Shell's statements about risks to the community were self-serving.

"History has shown that these early statements are for the benefit of industry public relations and not public health," Hadayia said.

Water may continue to be sprayed for up to 36 hours after the fire is extinguished to keep nearby equipment cool, Shell spokesperson Curtis Smith said on Sunday.

Olefins units are the central units in petrochemical complexes, producing ethylene, butadiene and propylene that are used to make plastics and other products like detergent and rubber.

(Reporting by Deep Vakil in Bengaluru; Editing by Lisa Shumaker)