§ 515.7 Transmission of official mail.
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
Subject to the requirements of law and of the regulations of the Post Office Department, franked self-addressed envelopes may be used for communications from the field staff to a State official designated by the Division and the Secretary of Labor, and for communication from the State agency to the Division or the Secretary of Labor.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.