Mexican State Seeks to Punish Pemex for Emissions from Cadereyta Refinery

Mexico's northern state Nuevo Leon on Sunday warned that it would seek penalties for state oil company Pemex after a dramatic increase in visible emissions from its Cadereyta refinery earlier in the day.

Video footage posted on social media, including by State Governor Samuel Garcia, showed thick, yellow and black smoke billowing from flare stacks - meant to burn off only small volumes of excess natural gas.

"We're going to impose harsh penalties for this incident," Garcia, who belongs to the Citizens' Movement, a party in opposition to the ruling National Regeneration Movement (MORENA), said in a video message.

"I've asked the environmental minister to be forceful and apply the law so that, whatever happens, I no longer see these types of events that pollute our air. We have the right to clean air in Nuevo Leon."

Pemex (PEMX.UL) said in a statement that it had "safely halted" operations in one of the plants at the Cadereyta refinery in the afternoon; the company added there was no risk to the population and the emissions were under control.

Nuevo Leon's environment ministry, however, said in a statement that it had repeatedly detected "intensified" emissions from the refinery, particularly at night, and that the refinery was responsible for 90% of sulfur dioxide emissions in the metropolitan area of Monterrey city, the state's capital.

The ministry said that state environmental law gave it the right, if necessary, to halt operations at the refinery.

Heavily indebted, Pemex is under intense international pressure, including from the United States, and its own bond investors, to clean up its operations after two vast methane leaks last year and excessive gas flaring.

(Reporting by Jackie Botts; Editing by Stefanie Eschenbacher)