The M4 was closed in both directions on Saturday as firefighters battled a fire believed to involve fireworks.
Emergency services were called to the Westbrook area near RAF Welford in Newbury for an incident they said could be caused by pyrotechnics.
Explosions were heard by passers-by who filmed huge piles of smoke rising above the site. It has not yet been confirmed whether the RAF base is where the fire broke out or whether there were any injuries.
The highway was reopened around 5:30 p.m.
The Royal Fire and Rescue Service of Berkshire said: “At 1:41 pm on Saturday, April 16, we received reports of a fire in an industrial building in Westbrook, Newbury.
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