(1) A tort doctrine that imposes joint liability on two or more parties if
their negligence combines to produce the same loss. (2) In property insurance,
this term refers to a situation where there is a mixture of covered and
uncovered perils acting together (either in sequence or simultaneously) to
produce the same property damage. In the early 1980s, lower courts in
California misapplied tort concepts to the interpretation of first-party
property policies and held that, in "concurrent causation" claims,
the property insurer is liable so long as one of the causes is covered by the
policy. As a result, these courts refused to enforce flood or earthquake
exclusions if there was an unexcluded factor contributing to the loss, such as
zoning decisions or the negligence of a contractor. In response, insurers added
so-called anti-concurrent causation (ACC) language to standard homeowners,
commercial property, and other first-party property policy forms to combat this
line of thinking. (3) In liability insurance, this term is occasionally used to
refer to a situation where there are two or more causes of action asserted in
the complaint against the insured, any one of which would be sufficient by
itself to hold the insured liable, but some of the causes of action are covered
and some are not. In that situation, the liability insurer must defend the
entire complaint.