When a manufacturer makes a product, they must consider the risks and harms that the product could cause. They do this because if a person is injured because of a defective product, the manufacturer will have to pay for the injury.
This has not always been the case. For a very long time, the "general rule" was that a manufacturer could not be sued, even for negligence, by someone with whom he had no contract. This was called the "rule of privity," and it was most famously set forth in an 1842 case Winterbottom v. Wright. This rule existed for many decades. See this article for more information about the history of product liability.
The law and its assumptions began to change in the middle of the 20th century. Many people consider Ralph Nader the true pioneer of Product Liability. According to his bio, "The crusading attorney first made headlines in 1965 with his book Unsafe at Any Speed, a scathing indictment that lambasted the auto industry for producing unsafe vehicles. The book led to congressional hearings and a series of automobile safety laws passed in 1966. Since 1966, Nader has been responsible for: at least eight major federal consumer protection laws such as the motor vehicle safety laws, Safe Drinking Water Act; the launching of federal regulatory agencies such as the Occupational Safety and Health Administration (OSHA), Environment Protection Agency (EPA), and Consumer Product Safety Administration; the recall of millions of defective motor vehicles; access to government through the Freedom of Information Act of 1974; and for many lives saved."
In Georgia, the following four part test must be meet for actions involving bodily injury to human beings. In any products liability case, the plaintiff has to prove: (1) that the product was defective, (2) that he or she actually was injured, (3) that that there was a connection between the product defect and the injury, and (4) that the defendant (manufacturer) was responsible for the defect. See Products Liability, Second Edition, Madden, §12.1, p. 487.
Upcoming: Part 2: Product liability - STRICT LIABILITY: O.C.G.A. §51-1-11