Breach of duty is when a person fails to live up to a legal obligation or responsibility that he or she has to another person. Primarily, breaches of duty are of a business nature (such as a breach of contract). However, they can also occur when a person has a duty toward another person that he or she fails to live up to such as following the speed limit and maintaining control over a vehicle to avoid causing a wreck.
If a person commits a breach of duty that results in an injury, then he or she can be sued. For example, a truck weigh station operator who fails to inform a truck driver that his load is too heavy can be sued if the overly heavy truck collapses a small bridge, resulting in injuries. Executives at companies also have various fiduciary duties. If these duties are breeched then they can be sued by other members of the company.