(Bloomberg) -- Kazakhstan’s operator of natural gas pipelines said planned maintenance on a compressor station resulted in a release detected by satellite last month.

Coordinates for the methane plume estimated by geoanalytics firm Kayrros SAS fall near the No. 6 compressor station of the Central Asia-China main pipeline in Kazakhstan, said KazTransGas JSC, a joint venture partner in the pipeline with China, in response to Bloomberg questions.

About 16,700 cubic meters of natural gas, or roughly 12.8 metric tons of methane, were released during the work on the compressor station July 24. That discharge was less than the emissions rate of more than 200 tons an hour estimated by Kayrros, KazTransGas said, and was within emissions quotas. Kayrros’s estimate didn’t include a duration for the event because it was based off a single satellite observation.

“KazTransGas JSC pays great attention to ensuring safety at its facilities, including environmental safety,” the company said by email. Kayrros’ estimate “doesn’t correspond to reality and couldn’t remain undetected by the gas company’s round-the-clock safety monitoring system,” it said.

The plume was observed roughly 100 kilometers (62 miles) west of Almaty, Kazakhstan’s largest city, and matched the pattern of methane releases observed from gas infrastructure, according to Kayrros. The firm uses data collected by the European Space Agency’s Sentinel-5P satellite, which typically captures observable releases that happen at a rate of 5 tons of methane per hour or greater. Kayrros didn’t comment on KazTransGas’s response.

The 1,833-kilometer Central Asia-China pipeline helps transport gas mostly from Turkmenistan through Uzbekistan and Kazakhstan to China. A release of roughly 200 tons of methane would have roughly the same short-term climate warming impact as the annual emissions of 10,000 cars in the U.K.

Multiple studies show that methane emissions from oil and gas infrastructure are often higher than what operators and governments report. Previous Bloomberg reporting on methane plumes based on Kayrros data has to led to public acknowledgment of releases from Russia. Public and private satellite data are helping spot methane plumes in countries including Canada and Australia.

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