Evanston Insurance Co.’s liability in a case in which a pregnant woman and her baby died after a tree fell on her is limited to $1 million, says a federal appeals court, in affirming a lower court ruling and holding there was only one occurrence.

In 2009, an old tree broke low on its trunk and fell on cousins Kaitlyn Griffin and Joshua Thacker, according to Tuesday’s ruling by the 6th U.S. Circuit Court of Appeals in Cincinnati in Evanston insurance Co. v. Housing Authority of Somerset; Kentucky Housing Authorities Self-insurance Fund Inc.; Jason Steele; Robin Mullins; Rhonda Kay Griffin.

Ms. Griffin died within minutes, and while doctors delivered the baby, Nicholas Ayden Steele, he died an hour after his mother, according to the ruling. According to a news report, she was 17. Her cousin, Mr. Thacker, was severely injured.

In December 2013, a state court jury found the Somerset, Kentucky-based Housing Authority of Somerset liable for the accident and awarded $3.7 million in damages.

The Housing Authority belonged to the Guthrie, Kentucky-based Kentucky Housing Authorities Self-Insured Fund, along with dozens of other municipal housing authorities, according to the ruling.

It had an insurance policy with Evanston, a unit of Glen Allen, Virginia-based Markel Corp., which provided a maximum of $1 million of coverage per occurrence, with an aggregate limit of $2 million.

Evanston filed suit in U.S. District Court in London, Kentucky, against the families, the Housing Authority and the fund, seeking a declaratory judgment limiting its liability under the fund’s policy to $1 million. Individual defendants claimed the coverage cap was between $2 million and $4 million.

The District Court ruled in Evanston’s favor, which was affirmed by a unanimous three-judge appeals court panel. There was only one occurrence, said the ruling.

“The individuals cannot solve this problem by claiming that different branches of the same tree caused the different injuries, creating three accidents, not one,” said the ruling.

“The individuals separately argue that the deaths arose from multiple causes — cardiac arrest in one case, blunt force in another — and thus that each qualified as an occurrence under the cause approach. But that is a variation on a defeated theme,” said the court in ruling in Evanston’s favor.