A business should absolutely not continue to produce and to market such a product. It would be wrong from at least two perspectives.
First, this would be wrong from an ethical perspective. Businesses should never act in ways that they know will hurt customers or others. Since this product will be very likely to hurt other people, and because the firm knows this perfectly well, it would be unethical to continue to produce it.
Second, this would be wrong from a business perspective. In our legal system, businesses can be held liable for selling products if they know those products are likely to cause harm. In this case, the business clearly knows that the product is likely to harm those who use it. Therefore, they would surely be held liable for any injuries. This would cost the firm a great deal of money. It would also hurt the firm’s reputation and make it harder for the firm to be profitable in the long run.
For these reasons, the firm should certainly not continue to produce and market the product.