A 23-year-old man was arrested as part of an investigation following an incident at a shop in Bootle on Bonfire Night.
Officers were called to Supersaver on Linacre Lane, at 8.40pm on Sunday 5th November, following reports a group of youths had thrown the fireworks into the shop.
A member of staff suffered a swollen eye believed to have been caused by flying debris but declined hospital treatment. A box of fireworks was seized and CCTV is being viewed.
Chief Inspector Chris Hitchell said: “This was clearly a very dangerous and stupid prank and could have had much more serious consequences.
“While the shop assistant was not badly injured they were left visibly shaken by the incident.
“This type of behaviour will not be tolerated and I would appeal for anyone who was in the vicinity of Linacre Lane at around 8.30pm who may have seen the group of youths close to the shop or running away from it to contact us.
“It is vital that we trace the person or people responsible and bring them to justice.”
Anyone with information is asked to contact Merseyside Police on 101 quoting incident 1224 of 5th November or via Crimestoppers anonymously on 0800 555 111.
A 23-year-old man from Bootle was arrested on suspicion of criminal damage. He has been released under investigation.