(CNN) -- A mushroom cloud of thick dark smoke hovered over the Puerto Rican capital after a blast ripped through a fuel storage complex near San Juan early Friday and caused a massive fire.



At least one injury occurred and at least 350 people have been evacuated as about 100 firefighters worked through the night to fight the blaze, Gov. Luis Fortuno said.



Firefighters said it would take a few days to control the inferno. Eleven tanks are ablaze, and firefighters are trying to cool down the remaining 29 tanks. The tanks are holding jet and diesel fuels and gasoline.



Authorities are looking into the cause of the blaze, which took place at Caribbean Petroleum Corp., a storage complex on San Juan's bay that owns the Gulf brand in Puerto Rico.



iReport.com: See, share, send images of the explosion



Justin Gehrke, a U.S. Army civilian employee who filed an iReport for CNN, was taken aback by the sight of the thick black smoke and took photos of the scene from his iPhone.



"I didn't expect to see a mushroom cloud from my house," he said.
What is iReport requesting of people to send them? Where was the explosion? What kinds of fuels did Caribbean Petroleum Corp hold? How many were evacuated near San Juan, Puerto Rico? What fuels did the Caribbean Petroeum Corp hold? where was the fire how many people were injured how many were evacuated
images of the explosion a fuel storage complex diesel at least 350 people jet and diesel near San Juan one injury at least 350
question: What is iReport requesting of people to send them?, answer: images of the explosion | question: Where was the explosion?, answer: a fuel storage complex | question: What kinds of fuels did Caribbean Petroleum Corp hold?, answer: diesel | question: How many were evacuated near San Juan, Puerto Rico?, answer: at least 350 people | question: What fuels did the Caribbean Petroeum Corp hold?, answer: jet and diesel | question: where was the fire, answer: near San Juan | question: how many people were injured, answer: one injury | question: how many were evacuated, answer: at least 350