Generally,the UCC uses the test of impossibility to determine if a person can be excused from performing his contractual obligations.

Impossibility

A defense in contract law where a party claims that fulfilling the contractual obligations has become objectively impossible due to unforeseen events.

Contractual Obligations

Responsibilities that parties are legally bound to perform as outlined in a contract agreement.

UCC

Uniform Commercial Code, a standardized set of laws and regulations intended to facilitate the smooth transaction of commerce among American states.