MEXICO CITY, Oct 12 (Reuters) - Mexican national oil

company Pemex's Deer Park oil refinery near Houston will operate

this weekend at a low level following a deadly chemical leak a

couple days ago, the company said in a statement late on Friday.

The state-owned oil company added that it continues to

investigate the cause of last Thursday's hydrogen sulfide gas

leak that killed two contract workers while injuring 35 others

during work on a unit at the 312,500-barrel-per-day (bpd)

refinery.

On Friday, Pemex's chief executive said that thirteen

workers remained hospitalized after being exposed to the leak,

while Mexico's energy minister said she expected the facility to

be back to normal operations later on Friday.

But the company walked back that expectation with its latest

statement.

"The refinery continues to operate in stable conditions at a

low level, a level that will be kept in place during the weekend

as long as it's possible to have access to the areas to carry

out the corresponding inspections," the company said in its

Friday night statement.

The U.S. Chemical Safety and Hazard Investigation Board

(CSB), which investigates industrial accidents and makes

recommendations to prevent future incidents, also has begun a

probe of what it described as a "very serious incident."