A firework blew up a toilet inside the Churchill Square shopping centre in Brighton.
Mess was strewn around the second-floor gents' room and the toilet bowl was shattered.
It was the latest incident in a spate of gunpowder vandalism.
A letterbox was blown up, a lamb was found dead after fireworks were hurled into a field, and a rocket was fired at a woman's home.
David Lepper, MP for Brighton Pavilion, is now taking up the issues of high-powered fireworks and sales to under-aged children with Government ministers.
Saturday's explosion at Churchill Square caused £250 worth of damage. A group of youths was filmed on video outside the toilets and police are trying to trace them.
Derek Maddison, centre manager, said: "The consequences could have been very serious, especially if children had been walking into the toilet at the time of the explosion."
A lamb was found dead and others were injured at a farm near Lewes after youths were seen throwing fireworks.
Farmers believe the lamb died after being trampled by frightened sheep.
One farmer, who wanted to remain anonymous in case vandals retaliated, said: "My sheep have been traumatised. The lambs are just three weeks old and were deliberately targeted."
Last week in Patcham, a letterbox was blown up and a Jaguar car was damaged by fireworks.
Vandals fired a rocket at a woman's house in Hove and then lobbed eggs through an open window, causing damage inside.
Mr Lepper said he had had no complaints from the public about fireworks this year but he was alarmed by the vandal attacks.
He said: "I will be asking a minister in the Department of Trade and Industry about whether the sale of high-powered fireworks should be restricted to display organisers and not members of the public across the counter."
He said he would also be asking ministers to look again at the problem of selling fireworks to under-age children.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article