The most common and most likely answer to this crossword clue is the 9 letter word VOLCANOES
I've seen this crossword clue in The Times
V
O
L
C
A
N
O
E
S
Buddy explains!
The straight part
We know that "they can produce lots of smoke!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they can produce lots of smoke! = volcanoes.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VOLCANOES mean?
VOLCANOES noun- A vent or fissure on the surface of a planet (usually in a mountainous form) with a magma chamber attached to the mantle of a planet or moon, periodically erupting forth lava and volcanic gases onto the surface.
- A form of firework.