Due to the impact of the explosion, the tin roof of the factory fell on the workers, trapping them.
A Fire department official said a call about the incident was received around 2.50 PM and five fire tenders were rushed to the spot.
The workers were rescued by a team of fire department, police and other agencies, a senior police official said.
Dilip (28) and his brother Vipin (19) suffered 90 per cent burn injuries and were rushed to Harish Chandra Hospital. Their condition is stated to be critical, he said.
Police are on the lookout of the factory's owner.
"We are trying to trace the factory's owner. A case of negligence will be registered against him," the officer said.