With bonfire night approaching, consumers are being urged to avoid buying cheap fireworks from unlicensed outlets or via social media.
The warning from local councils and the emergency services follows recent large-scale seizures of fireworks and incidents where fireworks let off by accident have severely damaging people's homes.
In one incident, Tyne and Wear Fire and Rescue Service seized almost 500kg of fireworks that had been stored in a garage alongside propane cylinders, petrol and live unsecured electrical wires.
The Local Government Association (LGA) and fire authorities have warned that buying fireworks from car boot sales, vehicles or private houses could pose a risk to life and property.
The LGA is also encouraging people and businesses to store fireworks securely to avoid injury and damage.
Cambridgeshire and Peterborough Trading Standards confiscated £2,000 worth of fireworks they found being stored illegally in a van and sold on social media.
In another incident a child let off a firework in a home in Wrexham, North Wales, that destroyed a kitchen in an incident attended by North Wales Fire and Rescue Service.
Simon Blackburn, chairman of the LGA's Safer and Stronger Communities Board, said: "Fireworks are explosives and can be extremely dangerous, uncontrollable weapons when used inappropriately.
"These dangers are magnified when using illegal fireworks which are made from inferior materials that can cause life-changing injuries.
"People should only buy fireworks from reputable and licensed sellers, rather than from unlicensed outlets, such as car boot sales, or through social media."
Anyone who suspects someone is selling fireworks illegally should contact their local council's Trading Standards via Citizens Advice on 03454 040506