Story highlights Pension bill passed Kentucky's House and Senate and heads to governor's desk

Changes to pension were put into sewage bill, in a move angering Democrats and teachers

(CNN) More than 20 Kentucky counties had schools close Friday after the state Legislature approved changes to their pension the day before.

Educators, who are furious over the pension issue, called out of work sick or requested substitutes in protest.

The bill, which overhauls the state's pension, passed mostly on party lines and heads to Gov. Matt Bevin, who supports reforming the system. State leaders say it's critical to fix the pension crisis, which ranks as one of the worst in the US

Kentucky teachers have opposed changes to their pension, which was in Senate Bill 1 that proposed reducing benefits.

But in a surprise move, elements of Senate Bill 1 were tucked into another bill, Senate Bill 151, which had been about sewage services, reported several CNN affiliates in Kentucky. And the new, nearly 300-page Senate Bill 151 passed both the state House and Senate on Thursday to the chagrin of teachers and retirees who crammed into the Capitol.