An apparent explosion sparked a fire at a massive Quaker Oats plant in Iowa on Saturday, sending thick black smoke billowing over downtown Cedar Rapids as firefighters rushed to the facility billed as the world's largest oat mill.No injuries were reported, and all workers were safely accounted for, according to local officials.The Quaker Oats plant is the world's largest milling facility, processing more than 2 million pounds of oats each day, according to the company's website.FIREFIGHTERS SAVE HISTORIC 'GODFATHER' CHURCH FROM RAGING NYC WAREHOUSE BLAZEFirefighters were called to the plant at...