The final type of defect centers on the alerts that a manufacturer is unable to provide about the hazards of the product. Under the Re-Statement (Third), the product may be defective due to insufficient directions or warnings when the potential risks of harm created by the product could have been prevented or lessened by giving reasonable directions or warnings by the seller or distributor and the neglect of the instructions or warnings that make the product unsafe.

A manufacturer has two duties to fulfill:

• One, the manufacturer is obliged to alert the users of hidden dangers that can be present in the product; and
• Two, the manufacturer must teach the users how to use the product so that the users can prevent any risk and use the product properly and safely.

For instance, a fan that is susceptible to overheat when it is operated beyond three hours continuously. Thus, after three hours, the fan can cause fire. If the manufacturer is unable to give a warning about the probable danger of the product, then the plaintiff who is injured in a fire started by the product can recover the defect in the design of the fan and for the insufficient warnings about the possible dangers caused by the fan.

Basically, a warning must be clear and particular. It must be visible and placed in an area that user will be able to find and read easily.  Nowadays, many manufacturers give warnings in different foreign languages and through symbols so that the children and the non-English speaking users will be able to understand the dangers related with the product.