You have been using baby powder, or talcum powder, for as long as you can remember. You always assumed it was safe. Then you started hearing that it could cause cancer and could be fatal.
If you ask Monsanto, the company that was recently bought by Bayer and that makes the popular weed killer Roundup, you will probably hear that Roundup is safe. They have been saying for years that it's fine to use it on agricultural products since it just kills things like invasive weeds and has no impact on people who then eat those crops.
Perhaps unsurprisingly, Bayer is not thrilled with the $2 billion verdict that went against them in a recent Roundup weed killer lawsuit in California. They have asked the judge for a reversal.
You have heard that talcum powder sometimes contains asbestos, which makes it very dangerous. If you breathe the powder in, the asbestos can cause cancer -- often, mesothelioma or lung cancer.
When a pharmaceutical drug or medical device is found to be unsafe, most of us would reasonably expect it to be pulled off the market immediately. After all, these products are under the regulatory authority of the Food and Drug Administration. Unfortunately, change almost never occurs so quickly. Dangerous and defective products remain on the market for years after problems are discovered, and most manufacturers will spend enormous amounts of time and money denying that their products are unsafe.