A more thorough explanation:

Definition: Exposure theory is a concept in insurance that states that an insurance company must provide coverage for a loss if the policy was in effect when the claimant was exposed to the product that caused the injury.

For example, let's say that a person was exposed to asbestos while working at a construction site in the 1980s. However, they did not develop any symptoms until 20 years later. Under the exposure theory, if the person had an insurance policy that covered asbestos exposure during their time working at the construction site, the insurance company would be required to provide coverage for their illness.

The exposure theory is different from the manifestation theory, which states that an insurance company must provide coverage only when the injury or illness manifests itself, or becomes apparent. The exposure theory is also different from the actual-injury trigger and triple trigger theories.

Overall, the exposure theory is an important concept in insurance that helps ensure that individuals are protected from the long-term effects of exposure to harmful substances.