the two sentences are in the passive voice.the first one is in the past perfect passive. the second in the past simple passive. we use the past simple for things that happened and finished in the past. we use the past perfect to express an action happened in the past before another action. The fire had been put out successfully before the firmen came.

除了时态的不同外，在表达的语气上，前者是暗示强调终于扑灭了火，过程很可能非常艰难，但是后一句只是平述出了火被扑灭的事实。情感方面是很不同的。