SHANKSVILLE, Pa. — An illness in the family is preventing Pennsylvania’s governor from attending an event this weekend to mark the 15th anniversary of the 9/11 attack at the site where United Airlines Flight 93 crashed.

A spokesman for Democratic Gov. Tom Wolf said Friday he will not be among those who will be in Shanksville.

The keynote speaker is Interior Secretary Sally Jewell.

The event will begin at 9:45 a.m. on Sunday, the anniversary, and will include a reading of the names of the 40 passengers and crew killed during the attack.

The site is now the Flight 93 National Memorial .