Police have issued as warning as school kids arranged to have a fight with acid and bleach loaded water pistols.
The planned fracas in Birmingham caused police to issue a Dispersal Order which prevents people gathering and means they can be asked leave an area if police suspect there will be trouble.
The order for the Northfield area was given after cops learned of the fight with the dangerous liquids.
Northfield Police @NorthfieldWMP tweeted: "There is currently a dispersal order in Northfield town centre due to reports that school-aged children were due to have a water fight whereby their water guns were filled up with acid and bleach."
Police can ask two or more people to leave a specified area if they think it may cause a nuisance to others.
They can also ask those involved to leave a specific area and not come back
The orders were brought as part of the Anti-Social Behaviour Act 2003.
Those who do not obey an order will have committed and a criminal offence.
Cops can also ask anyone under 16 to return to their home address.
Notices are enforced for up to 48 hours and anyone found breaching the ruling can be be arrested or charged.
Acid Survivors Trust International (ASTI) says the UK has one of the highest attack rates using acid in the world.
It tells how the UK does not have "tight controls on acid sales" or "legislation specific to acid attacks".
Sergeant Dave Taylor of Northfield Police said: "We work closely with schools in the area and concerns were raised to us that a large group of children, from different schools, were planning to gather for a water fight in Northfield town centre yesterday.
"There had also been talk of children planning to fill water pistols with corrosive substances. Thankfully there was no evidence of this but it's only right that we take steps to keep people safe if there is any suggestion of a risk to people's safety.
"My officers attended the town centre yesterday and there was a large group of children soaking each other with water. It was largely good-natured fun but we did move some children on, using dispersal order powers, as they were targeting shoppers and retailers."
The Mirror told in June last year how dispersal notices has been issued for three beaches during hot summer weather.
Formby Beach in Merseyside was affected and piers at Bournemouth beach in Dorset, where a "major incident" was declared after crowds flocked there on the hottest day of the year so far.
An identical order was also in place in Orcombe Point in Exmouth, Devon after up to 200 people were involved in a mass brawl in front of horrified families.
Five people were arrested on Formby Beach for various offences including drunk and disorderly behaviour and possession of drugs, and a speaker and music equipment was seized.
Police also confiscated BBQs and alcohol, with pictures showing officers searching bags and stopping cars en route.
