Mexican oil and gas companies, including state giant Pemex, are lagging behind on their obligations to identify, report and mitigate methane emissions from their installations, an investigation by a group of non-profits found.
Methane, a potent greenhouse gas that traps heat in the atmosphere, has emerged as a top threat to the climate.
Government regulation requires oil and gas companies to identify and measure their methane emissions, and submit a so-called program for prevention and integrated control of methane emissions (PPCIEM) to environmental regulator.
Investigators at the Mexican Methane Emissions Observatory, an alliance of three non-profit organizations, found that so far only 7% of regulated entities have submitted some of the required documents.
A company may need to respond to requests for documents for several parts of its operations.
Pemex, which dominates the sector, only submitted documents for two of its regulated entities - though the investigators highlighted that it was not certain whether this included all of the installations.
For the vast majority of installations in Mexico, there is no certainty on compliance, they found.
Pemex did not respond to a Reuters request for comment.
The documents were requested via Mexico's transparency institute from three different regulators and the energy ministry in November last year.
"Controlling the emissions of methane is what Mexico can and should do to comply with its international commitments," said Adrian Fernandez, a former environmental official, who founded the Mexico Climate Initiative, one of the nonprofits backing the alliance.
"There are huge challenges in mitigating methane emissions but at least in the oil and gas sector the technology already exists, and is accessible," he told Reuters in an interview.
Reuters reported last year that satellites recorded two vast methane leaks at an offshore platform belonging to Pemex in the Gulf of Mexico.
Mexico is the world's tenth biggest emitter of methane, according to the Global Methane Tracker 2022, published by the International Energy Agency.
Research increasingly shows that reducing methane output is vital to keeping global warming to within 2 degrees Celsius - above pre-industrial times - in order to avert the worst impacts of climate change.
(Reporting by Stefanie Eschenbacher; Editing by Aurora Ellis)