Diversity in product composition significantly affects the application of market share liability. When products are non-fungible and vary in their makeup – including variations in formula, design, strength, or toxicity – attributing equal culpability to all manufacturers is problematic. Market share liability usually requires fungibility wherein each manufacturer’s product is essentially identical and thus interchangeable, leading to an equitable attribution of liability according to market share.
For example: In cases involving asbestos exposure, where multiple types and brands exist with varying degrees of risk, assigning liability based on market share would inadequately address the differences in each product’s hazard levels.