Design defect

The design defect as a defined case in which liability is to be excluded under product liability law

Under the German Product Liability Act (ProdHaftG), a manufacturer is liable when a product defect causes a person to be killed or injured or a thing other than the defective product itself to be damaged. Above and beyond that, the ProdHaftG lays down five defined sets of circumstances in which the liability of the manufacturer should be excluded. One of these is the so-called design defect, which exists if the manufacturer was not able to recognise the dangerousness of his product at the time when it was placed on the market. Conversely, this means that a manufacturer cannot plead exemption warranted by a circumstance of this kind if the risk of the defect was recognisable to him. According to the volition of the legislators, the yardstick for this recognition should be the state of the art in science and technology. But what exactly lies behind this legal term

This is in fact a so-called indefinite legal term. That means that a generally accepted or statutory definition does not exist and that life has to be breathed into the term by the entity applying the law in each case.

In 1978, in its Kalkar-I judgement in a case involving atomic energy law, the Federal Supreme Constitutional Court (BVerfG) occupied itself intensively with the term for the first time and gave it some form and content. The BVerfG determined that the state of the art in science and technology always calls for the safety measure which keeps pace with both technological and scientific development. Translated to the manufacture of products, this means that a manufacturer, in the conception and manufacture of his product, must also take account of that which is considered necessary according to the most recent scientific insights. Explicitly, therefore, what is necessary has no limitation in what is technologically feasible.

In an adjudication in the year 2009, the BGH too demanded the state of the art in science and technology for the conception and manufacture of a product, and stated that it was not appropriate to assume that danger could be avoided until there was assured knowledge among experts that the relevant professional circles had practically deployable solutions available to them and had proceeded to apply them, those solutions constituting an alternative design which was superior from the point of view of safety technology and being ready for series production.

Recently, the Regional Court (Landgericht) in Freiburg adjudged a case involving an actual question regarding a design defect which would lead to exemption from liability if it were confirmed. The party against whom the complaint had been made was a manufacturer of hip prostheses which, after implantation in the plaintiff, had led to metal abrasion and consequent severe health damage. The attempt made by the manufacturer to make a procedural plea of a design defect failed, because scientific evidence of the defect potential had already been provided at the time when the prosthesis model about which the plaintiff was complaining was placed on the market, indicating that it could therefore have been recognised by the manufacturer.

Practical significance

The state of the art in science and technology which is authoritative for the conception and manufacture of products must on no account be confused with what is usual or customary in the sector or trade, or equated with what has gained acceptance and proved its worth in practice. What is called for here is much more than the mere application of standards, which assume great relevance in practice, in particular from the points of view of product safety law. The fact is that these often lag behind technological progress and are thus, in the best case, suitable to help depict the state of technology. So however great the pressure of innovation caused by the competition, the manufacturer of a product is required to obtain scientific insights regarding the safety of his product, analyse them and carry out adequate testing. Thus it is all the more important to earmark appropriate resources for obtaining those insights in good time, and to safeguard the required quality of products, particularly in a supply chain, by means of appropriate quality assurance processes and agreements. According to the general rules on the burden of proof, it is always the manufacturer who bears the burden of proof for the existence of a design defect.

[April 2019]