BEIJING — China has imposed a potentially crippling $1.3 billion fine on the company responsible for faulty vaccines given to hundreds of thousands of children, sending its strongest signal yet of a stricter legal environment for the scandal-prone industry.

The fine against the Changchun Changsheng Biotechnology Company dwarfs previous penalties imposed on vaccine makers embroiled in safety scandals. It comes at a time of increasing anxieties among the country’s growing middle class, already furious about a spate of drug and food safety scandals that have threatened its sense of security.

“The government is imposing this heavy punishment to build effective order,” said Wang Yuedan, professor of immunology at Peking University. “From now on, no one will dare to touch this high-voltage wire.”

The government also barred Gao Junfang, the company’s chairwoman, and 14 other executives from working in the vaccine industry. They are still under investigation and could face criminal penalties.