What does the cryptic crossword clue "Large tank has me kept in storage when explosive (9)" mean?

The definition is "Large". The wordplay uses an anagram. anagram of ME + STORAGE = GASOMETER; definition: "Large tank" The answer is Gasometer.

Large tank has me kept in storage when explosive (9)

Telegraph Prize Cryptic #3073 | 17 Across | 2020-09-13 flower