Mandeep (22) and Anil Kumar (21) were killed in the incident, police said.
After the blast, the roof of the factory collapsed and around a dozen labourers got buried under the debris.
About 60 security personnel, mainly from the ITBP, launched a rescue operation.
Six fire tenders and two cranes were pressed into service to pull out the labourers buried under the debris, according to police.
The six injured were admitted to Civil hospital at Ambala City, from where three of them were referred to PGIMER at Chandigarh, following their serious condition.