A manufacturing defects may occur in the construction or production of a product. A product has a manufacturing defect if (1) it differs from the manufacturer’s design or specifications (the product departs from its intended design) making it more dangerous than consumers expect it to be; and (2) the products that were manufactured or produced differently are from the same manufacturer and were intended to be identical.

Although manufacturing defects are relatively uncommon, if a product has a manufacturing defect, the manufacturer will be strictly liable in tort for damages caused by the defective product. This means the manufacturer will be liable even if the manufacturer exercised great care in manufacturing the product and was not negligent.

Products liability laws vary from state to state and may be in a state’s statutes or in its court opinions (also known as case law or common law).

In New Hampshire, if a product has a manufacturing defect, it means that the product deviates from the manufacturer's intended design or specifications, making it unexpectedly dangerous for consumers. New Hampshire adheres to the doctrine of strict liability in tort for manufacturing defects. Under strict liability, a manufacturer can be held liable for damages caused by a defective product without the need for the injured party to prove negligence. This means that if a product causes harm due to a manufacturing defect, the manufacturer may be responsible for compensating the injured party, regardless of the level of care taken during the manufacturing process. New Hampshire's product liability laws are derived from a combination of state statutes and judicial opinions. It is important for manufacturers to ensure that their products meet safety standards and design specifications to avoid liability for any potential manufacturing defects.