LONDON — United States, Portuguese and British authorities are investigating what caused a cargo ship to collide with an oil tanker carrying jet fuel for the U.S. military off the coast of eastern England Monday. With the fire still blazing, British government minister Matthew Pennycook said Tuesday morning the three governments were working together after the crash set both vessels alight and triggered a major rescue operation. But he refused to speculate on potential causes, including foul play. The U.S. Stena Immaculate chemical tanker was carrying around 35 million liters of aviation fuel for the U.S. Navy’s Military Sealift Command. The fuel has a high boiling point, meaning it evaporates slowly and is relatively toxic. It collided with the Portuguese Solong vessel, which had 15 containers of toxic sodium cyanide on its cargo. CBS News cited an unnamed American sailor on board the Stena Immaculate who said “a massive ship came from out of the blue” and collided with the tanker. One crew member from the Solong is still missing, with a search called off last night. Its other 13 members are accounted for, with all 23 crew members on the Stena Immaculate also accounted for. Pressed on the incident Tuesday, Pennycook told the BBC that the U.K. coast guard and emergency services were responding to a “particularly fast-moving, dynamic situation.” “There’s only a certain amount I can say at this point in time, but investigations are taking place as to the causes of the crash,” the British government minister said. “That’s led by U.S. and Portuguese authorities as the flag states for the ships concerned, but it’s being assisted by U.K. authorities and the appropriate authorities in terms of … the potential environmental impact.” He added: “The fire is still raging. So as I say, it’s a dynamic situation, but we think in terms of things like air quality levels, they are within safe limits as things stand.” Pressed on whether the government could rule out foul play, Pennycook said: “I’m certainly not going to add to that speculation about the causes of the crash. I think what is appropriate is that investigation is allowed to take place.” He vowed the three countries would “get to the bottom of why this incident happened.” The U.S. Coast Guard confirmed Monday night it was sending investigators to the U.K. to assist the probe. A Coast Guard spokesperson said it was “actively engaged with the United Kingdom’s Marine Accident Investigation Branch and Portugal’s Marine Safety Investigation Authority to coordinate joint evidence-collection efforts” at the scene of the crash. “Investigators from the U.S. Coast Guard and U.S. National Transportation Safety Board are deploying to the United Kingdom to conduct the investigation over the coming days,” they added. Karl Mathiesen contributed to this report.