(Adds Calpine postpones reopening, cases up sharply Thursday)
By Liz Hampton and Jennifer Hiller
HOUSTON, June 24 (Reuters) - U.S. energy companies slammed the brakes on returning staff to their Houston offices as COVID-19 cases soared and top hospitals warned they could soon run out of beds for the most severely ill patients.
Texas officials imposed restrictions as new cases in the state topped 5,000 on three consecutive days as of Thursday. Intensive care unit (ICU) beds were 97% full at Houston's Texas Medical Center, which said it may soon move to increase ICU capacity assignments, officials said.
Texas Governor Greg Abbott has announced a phased reopening of shops, bars and amusement parks from May 1, and businesses have rolled out their own office restarts. But on Wednesday, he warned of a "massive outbreak" and urged people to stay at home.
Many energy firms qualify as essential, and therefore are free to staff normally, but the surge in illness and hospitalizations has prompted large employers to delay or halt openings.
Halliburton Co, the second-largest U.S. oilfield service company by revenue, delayed for two weeks a second phase of its return-to-work plan, and power producer Calpine pushed back the start of returning non-essential workers to offices until August from July 6, representatives for the two companies said.
Chevron also has delayed its reopening plans for further evaluation, said spokesman Sean Comey. About 5% of its Houston office staff and about 2% of its San Ramon, California, workforce are in their offices now, he said.
Midcoast Energy, a natural gas pipeline company, reopened on June 1 but sent Houston employees home three weeks later after two tested positive for the virus, said a person familiar with the matter. President Robert Bond did not respond to requests for comment.
Exxon Mobil, Phillips 66 and ConocoPhillips returned some white-collar workers to their campuses in May or this month. Exxon will remain below 50% capacity at its Houston-area facility, a spokesman said. Conoco is prepared to change its return-to-office plan if needed, a spokesman said.
Phillips 66 said the vast majority of its staff had returned and would remain working from their offices.
"We are a critical infrastructure industry and have an ongoing obligation to continue operating," spokesman Joe Gannon said, noting that the company follows Centers for Disease Control and government advisories. (Reporting by Liz Hampton, Jennifer Hiller, Erwin Seba and Gary McWilliams; editing by Richard Pullin and Richard Chang)