CONSTRUCTION DEFECT JOURNAL

"News and Information for Construction Defect and Claims Professionals"

CONSTRUCTION DEFECT JOURNAL - ISSUE 242749 - WEDNESDAY, JUNE 24, 2026

Montana Supreme Court Tackles Decade-Old Coverage Dispute Concerning Asbestos Mineworker Claims

Mining equipment

The court addressed issues including the duty to defend/estoppel, the number of occurrences, “trigger of coverage,” and, in a case of first impression, allocation under Montana law.

December 20, 2021
Patricia B. Santelle & Paul A. Briganti - White and Williams

On November 23, 2021, the Montana Supreme Court issued an almost unanimous decision in National Indemnity Company v. State of Montana, a ten-year-old coverage dispute arising from claims against the State of Montana alleging it had failed to warn of asbestos dust conditions at vermiculite mining and milling operations in and around Libby, Montana (the Libby Mine) run by W.R. Grace & Company and its predecessors. Affirming in part and reversing in part rulings by the trial court that culminated in a $98 million judgment against the State’s CGL insurer from 1973 to 1975, the court addressed issues including the duty to defend/estoppel, the number of occurrences, “trigger of coverage,” and, in a case of first impression, allocation under Montana law.

Whether the Insurer Breached the Duty to Defend Depended Upon the Timeframe
The court looked at whether (1) the insured provided sufficient information to bring the claims within the possibility of coverage under the subject policy and (2) the insurer gave “the necessary substance to” fulfilling its duty to defend at four points in the relevant timeframe:

  1. The insurer did not breach its duty at the time the State initially tendered the Libby Mine claims because the State defended the claims through its self-insurance program, hired its own counsel, managed the litigation, made its own defense decisions, and took the position with the insurer that the matter was “under control” and “nothing was left to be done[.]”

Reprinted courtesy of Patricia B. Santelle, White and Williams and Paul A. Briganti, White and Williams
Ms. Santelle may be contacted at santellep@whiteandwilliams.com
Mr. Briganti may be contacted at brigantip@whiteandwilliams.com


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