Two persons were killed in West Bengal early on Thursday when a container-trailer collided with a gas tanker on the Kona Expressway in the Howrah district, an official said."The crash took place around 3.50 a.m. There was an explosion and both the vehicles caught fire. Charred remains of both drivers were recovered," a Jagacha police station official said.Seven fire tenders worked for about an hour and half to put out the blaze, a fire official said.The expressway traffic was affected. Officials temporarily suspended vehicular movement to clear the road.