A tanker carrying around one million barrels of bitumen mix was involved in a collision near the Chinese port city of Qingdao, spilling oil into the Yellow Sea, Chinese maritime officials and tanker representatives said on Tuesday.

The collision involving the anchored Liberia-flagged tanker A Symphony and the bulk vessel Sea Justice took place at 0850 local time (0050 GMT), A Symphony’s manager Goodwood Ship Management said in an e-mail.

“The force of the impact on the forward port side caused a breach in cargo tanks and ballast tanks, with a quantity of oil lost into the ocean,” Goodwood said, adding all of the crew had been accounted for and there were no injuries.

It was not immediately possible to contact the owner of the Sea Justice.

“The oil spill came after a clash between two vessels,” an official for China’s Shandong Maritime Safety Administration told Reuters on condition of anonymity, confirming that no one was injured.

Heavy fog, which has hampered navigation off the Qingdao coast since Monday, led to poor visibility at the time of the collision, Goodwood said.

“Immediately after the allision (violent striking) occurred, the master initiated emergency procedures onboard, mobilizing the vessel’s oil spill response team and initiating an internal transfer to limit the loss of product,” Goodwood said in an emailed statement.

It said the incident was reported to local authorities and steps to contain and clean up the oil had begun, although the port’s closure because of “zero visibility” was hindering the efforts.

The Shandong Maritime Safety Administration has instructed other ships in the area to stay at least 10 nautical miles from the A Symphony, but did not provide details on how much oil has leaked.

The A Symphony, a Suezmax tanker, was last seen near the Qingdao port, live shipping data on Refinitiv Eikon showed.

The tanker called at Linggi International Transhipment Hub, near Malacca in peninsular Malaysia, earlier this month, where it fully loaded with oil and set sail for China, the data showed.

Contacted by Reuters, an executive at Run Cheng International Resource (HK) Co said the company owned the 150,000-tonne cargo of bitumen blend on board A Symphony.

Bitumen, a mixture of hydrocarbons from residue in refining, is used for road surfacing and roofing. However, shipping sources said bitumen is typically moved in smaller vessels with specialized heating rather than suezmaxes.

The 272 meter-long and 46 meter-wide oil tanker was sold in May 2019 to its new owners Symphony Shipholding SA and NGM Energy, Equasis data showed.

Symphony Shipholding SA and NGM Energy could not be immediately reached for comment.