I suspect the Nabisco plant in Chicago pulls about ~12 million therms worth of natural gas, at 30kwh per therm, that's pretty significant.
You "suspect", but your suspicion comes with a unit of energy, which simply does not make sense in the context. The rest of us are talking about effect.
A quick google says that the entire city of Chicago draws about 3.4GW - are you saying that one bakery uses over 2/3 of the draw of the entire city?