Go to Data Catalog and search for employee_ssn in the search box.

Write a shell script that uses the bq command line tool to loop through all the projects in your organization.

Write a script that loops through all the projects in your organization and runs a query on INFORMATION_SCHEMA.COLUMNS view to find the employee_ssn column.

Write a Cloud DataFlow job that loops through all the projects in your organization and runs a query on INFORMATION_SCHEMA.COLUMNS view to find employee_ssn column.