Strict products liability was born in California and many states still look to California law for guidance on products liability law issues. For that reason, it is worth noting that late last August, the California Supreme Court issued its decision in Kim v. Toyota Motor Corporation in which it was asked to determine whether, in a strict products liability action, evidence that a product’s design conforms with industry custom and practice is relevant and admissible. Several appellate decisions in California had previously had held that such evidence is categorically inadmissible, but the lower appellate court in Kim had taken a different approach, saying "it depends.”
In a 5-2 decision, the court acknowledged that evidence that a product was manufactured following the custom does not, by itself, prove that the product is not defective, but the court held that evidence of industry custom and practice may be relevant for other purposes, “including the jury’s evaluation of whether the product is as safely designed as it should be, considering the feasibility and cost of alternative designs.” In other words, the court held that the evidence can be used together with other evidence as part of the analysis to determine whether the product is defective.
This result is actually not that surprising and it follows the general approach developed by courts following the Restatement 2d's approach to products liability (as opposed to the one in the Restatement 3d, which is followed by a minority of jurisdictions.)
You can read the opinion here.
You can read more about the case here.