Powderject knew for almost two years that batches of the BCG vaccine against TB had failed quality checks but failed to tell health regulators, according to a BBC investigation.
The potential fault was only discovered by a "crash inspection" by the Medicines Control Agency.
Lord Drayson, who was made a minister for defence procurement by Tony Blair in May, is said to have failed to reply to questions about the alleged failure. The peer sold his interest in Powderject in 2003.
According to an investigation by the BBC's Money Programme to be broadcast tomorrow, Powderject first uncovered the potentially critical fault during internal checks in 1989.
The programme has uncovered a damning report by health regulators following an inspection 21 months later.
Millions of schoolchildren have been inoculated with the vaccine and an unknown number may have received no immunity to TB. Cases of the lung disease have increased dramatically in recent years.Reuse content