Antibiotics handed out at the mass sterilisation could have contained a chemical compound found in rat poison.
Mahawar Pharmaceuticals is now at the centre of a probe into more than a dozen deaths in eastern India.
The country's efforts to rein in population growth have been described as the most draconian after China.
At least 13 women died as a result of a state-run sterilisation programme.
Ten more women who also had the procedure are in a serious condition.
Attempted murder, waging war on the state, criminal intimidation and fraud are some of the charges.