At least 12 people were killed and 58 more were injured following explosions at a chemical factory in western India on Saturday, police said.

Some more workers may be trapped inside as rescue operations continued at the plant located on the outskirts of Dhule city in Maharashtra state.

"Twelve people were killed and 58 were injured. Most of them were factory workers, some victims were farmers and residents in nearby areas," regional police chief Vishwas Pandhare said.

"There was an explosion in a barrel containing chemicals that apparently set off a series of similar explosions," he added.

The explosions were so loud that they were heard in a radius of 5 kilometers, its tremors shaking houses and buildings in the vicinity, news reports said.

News channels showed footage of clouds of black smoke billowing from the factory.

Police said there could be more workers trapped in the factory, adding there were accounts that said there were up to 100 workers at the site at the time of the accident.

The death toll could rise as the condition of some injured was said to be serious, he added.

Firefighters had got control of the blaze, Pandhare said, adding disaster management workers and police were inside the factory carrying out rescue work.

Accidents and fires are fairly common at Indian factories where safety standards are often disregarded.