A sample of the material was sent to a lab in Lucknow today for analysis.
As many as 62 sacks containing the powder were found last night, when after rainfall they started emitting ammonia gas and smoke. The odour was so foul that locals called the police and the fire brigade, Circle Officer of Babupurwa police station Pavitra Mohan Tripathi said today.
The owner of the godown, Kuldeep Kapoor, has claimed that the sacks were filled with aluminium powder.
A case has been registered against Kapoor and he has been detained for questioning, Tripathi added.