At least three workers were killed and several more injured in a suspected boiler blast in a private company in the MIDC industrial complex in Dombivli city here on Thursday morning, police said.The blast ripped through a boiler in the Herbert Brown-Acharya Pharma chemical company in Phase II of MIDC, on the outskirts of the city.The blast impact, which was described like a 'bomb explosion' by some witnesses, was heard in an area of four-five km, and shattered the glass windows of several buildings and complexes in the vicinity, besides disrupting mobile communication services.Fire-tenders and water tankers were rushed to the spot to tackle the emergency. The cause of the blast was being ascertained.