An investigation was launched after the explosion on Tanfields, in Skelmersdale, shortly after 6.05pm on Tuesday.
Five people managed to get out of the building before emergency services arrived and did not have any serious injuries.
A man later attended Ormskirk Hospital with burn injuries, which were not life-threatening.
Police say they are keeping an open mind on the cause of the explosion while the investigation continues and at this stage it is being treated as unexplained.
A 29-year-old man from Darlington has been arrested on suspicion of production of a class B drug and causing an explosion likely to endanger life or cause serious injury.
Detectives now want to speak to 40-year-old Robert Nolan, from Skelmersdale, as part of their inquiries.
He is described as white, around 5ft 8ins tall, of slim build and speaks with a Liverpool accent.
Det Con Sean Reddington, of Lancashire Constabulary’s South CID, said: “This incident has caused significant damage to the properties and left a number of people displaced.
“Our investigation is very much ongoing to establish the cause of the explosion and we would ask people to check any footage they may have covering the area to see if they have captured anything which could assist us in our enquiries.
“Although we are keeping an open mind as to what caused the explosion, we have made an arrest. We now need to speak to Robert Nolan as we believe he can assist us with our enquiries. We would ask anybody who sees him or knows where he is to contact police as soon as possible.”
Anyone who saw anything suspicious earlier in the day of the incident or in the period directly after the explosion is asked to contact the police.
They also want to hear from anybody who saw suspicious vehicles in the area in the days before the explosion.
People are asked to check their CCTV, dashcam or doorbell footage to see if they have captured anything which could assist the investigation.