Thousands of students in some of the Oklahoma City metro's largest districts are back in class Thursday.| MORE | KOCO Chronicle: State of Our Schools superintendent roundtableOne of the challenges is a massive teacher shortage. To help fill the void, the Oklahoma State Department of Education issued a record number of emergency teacher certifications last month – nearly 1,500. KOCO 5 recently spoke with superintendents from across Oklahoma about the teacher shortage."We emergency certified more teachers this year than I have at any time in my entire 10 years of Harrah. I don't see that going away," Harrah Public Schools Superintendent Paul Blessington said."Overwhelming. The biggest chunk is special education teachers," Oklahoma City Public Schools Superintendent Sean McDaniel said.| MORE | Oklahoma school districts put heavy emphasis on safety as students return to classThey said the shortage has been growing since the 2018 teacher walkout but recently accelerated during the COVID-19 pandemic.