Up to 150 workers were believed to have been inside the factory, which produces syringes and other plastic medical supplies, at the time of the explosion.

Choose your answer: based on the paragraph above can we conclude that "The explosion did not happen when the plant was empty but when employees were there."?

Available choices:
(i). Yes.
(ii). It's impossible to say.
(iii). No.
I think the answer is
(i).