で火災が発生

a fire broke out at

→ で
phrase Rare #32,716
a fire broke out at Used in formal or news-style language to report that a fire started at a particular place. The location before で can be translated as “at” or “in.”
JA: 駅の近くで火災が発生した。
EN: A fire broke out near the station.

ビルの中で火災が発生したらどうすればいいかわかりますか

Do you know what to do if a fire breaks out in a building?

町の中心部で火災が発生した

A fire broke out in the town center.

町の真ん中で火災が発生した

A fire broke out in the middle of town.