The hotel said there was only a small chance of eruption, so it was safe.
この場合、次のような言い方ができます。
ーThe reason why the hotel didn't give me back my money for the hotel room was because they said there was only a small chance of eruption, so the hotel was safe.
「ホテルが私のホテル代を返金してくれなかった理由は、噴火のリスクが低くホテルは安全だという理由からです」
The hotel said there was only a small chance of eruption, so it was safe. で「ホテルは噴火のリスクは低く、ここは安全だと言った」
a small chance of eruption で「噴火の確率は小さい」＝「噴火のリスクは低い」と言えます。
ご参考まで！
カナダ 
