Classes at Golden and Jefferson high schools are canceled today because of a large portion of teachers called in either claiming to be sick or using a personal day.

At Golden, Jeffco officials said, 81 percent of teachers requested a substitute. It was not clear how many teachers requested a substitute at Jefferson.

It’s the second time this month that Jeffco Public Schools is canceling class due to a high number of teacher absences.

It’s unclear why the teachers are calling out en masse. But tension between the suburban community’s teachers and school board has been rising for months. It reached a symbolic boiling point earlier when the Jefferson County Education Association voted no confidence in board chair Ken Witt. The union denied having any role in the earlier sick out.

The apparent Golden sick out follows a week of protests organized by students. Students are upset about a proposed curriculum review committee they believe could lead to censorship. No action has been taken by the school board on the committee.

Previously, classes at Standley Lake and Conifer were canceled Sept. 19, when about a third of teachers at those schools missed classes.