FIREFIGHTERS battled to douse a fire on a container ship loaded with 52 tonnes of fireworks last night after a collision with another vessel a mile northwest of Green Island. Two containers aboard the California Lunna, which was laden with fireworks, burst into flames when it collided with the Tang He. The fire spread to four other containers. The ship was towed to a safer spot out of the harbour fairways and although the crew was still on board late last night, they were moved to a safe distance from the seat of the blaze. Marine Department officers and three fireboats rushed to the rescue after the Fire Services Department was alerted at 7.26 pm. 'We have no explanation of how the crash happened or why the fire began,' the Marine Department said. Weather conditions at the time were fair. The 243-metre Panama-registered California Lunna was leaving Kwai Chung and the China-registered 170 m Tang He was entering Hong Kong from Shanghai when the collision occurred. Last week a massive rescue operation saved 21 men when two cargo vessels collided in the South China Sea. One man died and four are still missing presumed dead.