Johnson & Johnson says its product is safe. But asbestos, a carcinogen that can exist underground near talc, was a concern inside the company for decades.

The memos were concise and direct.

An executive at Johnson & Johnson said the main ingredient in its best-selling baby powder could potentially be contaminated by asbestos, the dangerous mineral that can cause cancer. He recommended to senior staff in 1971 that the company “upgrade” its quality control of talc.

Two years later, another executive raised a red flag, saying the company should no longer assume that its talc mines were asbestos-free. The powder, he said, sometimes contained materials that “might be classified as asbestos fiber.”

The carcinogen, which often appears underground near talc, has been a concern inside the company for decades. In hundreds of pages of memos, executives worried about a potential government ban of talc, the safety of the product and a public backlash over Johnson’s Baby Powder, a brand built on a reputation for trustworthiness and health.