West Midlands Fire Service was called to Garratts Lane just after 8pm on Tuesday.
The blaze involved a quantity of paint on fire, along with some gas cannisters which had exploded, and the fire had spread to a nearby field and neighbouring property.
A spokesman for West Midlands Fire Service said: "At 8.06pm on Tuesday, West Midlands Fire Service were called to reports of a fire on Garratts Lane, Cradley Heath.
"Our fire control room used mobile phone footage from callers to identify how many appliances to send, and the first of our crews arrived three minutes after being mobilised.
“Crews from Brierley Hill, Haden Cross and Smethwick attended a large fire in an industrial unit, with bulk containers, paint and paint thinner on fire, along with some gas cannisters which had exploded, and the fire had spread to a nearby field and neighbouring property.
“Using five main jets and one hose reel jet, crews were able to extinguish the fire, with our thermal imaging camera identifying no other hot spots.
"No one was harmed during the incident.
"We worked with our colleagues at West Midlands Police, West Midlands Ambulance Service and the Environment Agency during and following the incident to close the road to ensure public safety.
"The cause of the fire is under investigation.”