An "over-enthusiastic" chemistry student is thought to be behind a bomb alert sparked in Lancashire.
Four controlled explosions were carried out
Police searched the house on Grane Street, Haslingden, on Tuesday afternoon and found materials thought to be used to make bombs.
More than 40 people living nearby were moved to safety as four controlled explosions were carried out.
A 17-year-old was arrested on suspicion of possessing explosive devices but police said it was not a terror alert.
Detectives in Lancashire said the youth would be questioned on Wednesday.
Supt Neil Smith said: "What I can say is that - just so that we can reassure local people - this is not a terrorist incident.
"We believe it's a local A-level chemistry student that's been a little bit too enthusiastic."
A 100m cordon was put in place around Grane Street on Tuesday.
Homes were evacuated and residents were moved to the nearby Haslingden Leisure Centre.
The ambulance service was put on standby as police carried out four explosions between 1150 GMT and 0200 GMT.