Photo: Screenshot of a tweet on Tuesday by Tanker Trackers, an online service that tracks shipments of crude oil.

Hundreds of tons of oil might have leaked into the sea after a tanker collision off Qingdao, East China's Shandong Province. Maritime authorities have sent a dozen vessels to the site for an emergency clean-up, the Shandong Maritime Safety Administration (MSA) told the Global Times on Wednesday. 

The Suezmax tanker A Symphony registered in Liberia had a hole about six to seven meters long and two meters wide above the sea surface after being rammed by an inbound Panamanian bulk carrier Sea Justice while the tanker was at anchor, an official of the Command Center of the MSA who asked to remain anonymous revealed to the Global Times.

A preliminary investigation found that the oil leak might be hundreds of tons, showing an oil slick 3 kilometers long and 600 meters wide, he said, adding that the exact amount of the oil leak is unknown as the situation in the ocean has to be further verified.

The collision happened at about 8:50 am on Tuesday, Goodwood Ship Management was quoted as saying in a report by Reuters. The MSA said it received a report around 9:15 am. 

The bulk carrier collided with the oil tanker when the latter was at anchor southeast of Chaolian Island off Qingdao in heavy fog, with visibility of less than 200 meters, the MSA official said.

No injuries were found among the crew, he confirmed to the Global Times. The damaged ballast tank had cargo of 10,061 tons, of which about 2,000 tons was pumped out and transferred to other undamaged ones, he noted.

The tanker was fully laden with 1 million barrels of oil, according to a tweet on Tuesday by Tanker Trackers, an online service that tracks shipments of crude oil.

The cargo aboard the tanker was declared as "bitumen solution," but the specific content - heavy oil, light oil or other materials - requires further testing, the MSA official noted. 

The bulk carrier had 20,000 tons of peanut dregs, he said, noting that the bulk vessel had a dented bow but was not broken.

A marine patrol ship and 12 other ships have been sent to the scene for clean-up operations. 

"The oil leak is in full disposal now and if technological controls are in place, it will certainly keep the impact on the environment to the minimum," the MSA official told the Global Times, noting that a follow-up evaluation will be needed to determine if the oil spill will expand. 

The port of Qingdao remains open and in normal operation as the site of the collision is distant from the port, the Global Times learned from Qingdao Port on Wednesday. 

The Shandong Provincial and Qingdao Maritime Search and Rescue Center launched an emergency response after the incident, sending vessels and rescue forces to the scene, according to a notice that the Shandong MSA posted on Wednesday. 

The MSA alerted vessels to remain at least 10 nautical miles from the site of the collision in the Yellow Sea, according to a notification by the MSA on Tuesday.