This year's implementation of a 2010 state law may mean an estimated 1,500 Arizona third-graders will be denied promotions to fourth grade for not meeting required reading levels.

The Arizona Republic reported that estimate comes even as educators in many districts and individual schools ramp up reading instruction in third grade and lower grades.

State Superintendent of Public Instruction John Huppenthal said the third grade is "make or break" for students because those who can't read by fourth grade start to disengage from the educational process.

The 2010 law exempts English-language learners and students in reading and language special-education programs.

The estimate of 1,500 third-graders -- nearly 2 percent of the statewide enrollment -- being held back is based on scores of tests from last year.