BAKU - Azerbaijan's oil exports via the Baku-Tbilisi-Ceyhan pipeline, fell to 16.2 million metric tons in the January-July period, a decline of 5.9% from a year earlier, Azerbaijani data showed, as the route was marred by tainted oil.

The BTC pipeline, which runs through Georgia to Turkey, is used to export oil from the Azeri, Chirag and Guneshli oilfields, which are operated by BP.

The fall in exports reflects a long-term decline in production as Azerbaijan's oil reserves gradually deplete.

But organic chloride was also detected in Azeri BTC crude cargoes last month, pushing price differentials to a four-year low and delaying loadings.

Organic chloride is used in the oil industry to boost extraction from oilfields and must be removed before crude enters pipelines. The extent of the contamination and its impact on customers remain unclear but oil loadings from Ceyhan were disrupted for several days.

Azeri BTC loadings from Ceyhan totalled 423,000 barrels per day (bpd) in July, according to data from analytics firm Kpler, below the 561,000 bpd scheduled on the loading programme.

Azerbaijan's total oil transit in the first seven months of the year amounted to 21.6 million tons, of which 75.0% flowed through the BTC, according to the country's statistics committee.

The volume of transit oil sourced from other countries such as Kazakhstan and Turkmenistan via the BTC fell to 2.645 million tons from 3.214 million tons in the same period of 2024, the data showed.

(Reporting by Nailia Bagirova; Editing by Kirsten Donovan)