MINNEAPOLIS (AP) — Shares of Boeing Co. are falling for a second day as investors worry about the fallout from a fire aboard a new 787.

The fire happened on the ground and no one was hurt. But fire officials say it involved one of the plane’s lithium ion batteries. The 787 is Boeing’s first plane to use those batteries. In 2007 federal officials issued special rules for them because of concerns about the risk of fire.