You can send a written request for bulk orders of Social Security publications to:

Social Security Administration
Office of Supply and Warehouse Management
239 Supply Building
6301 Security Blvd Baltimore, MD 21235

The phone number for the Public Information Distribution Center is (410) 965-2039. You can also reach them via fax at (410) 965-2037 or email them at OPLM.OSWM.RPT.Orders@ssa.gov.