Rechecking the SPP, and its not formed from an EO but a trilateral agreement with Canada and Mexico. It is linked to the Department of Commerce. Through them, you can request documents via FOIA.
How to File a FOIA Request
A FOIA request can be made for any agency record that is not publicly available. Describe as best as possible the records you are requesting. In your description include information such as the date and place the records were created, the file descriptions, subject matter, persons involved, and other pertinent details that will help identify the records. Please be aware that the FOIA does not require agencies to answer questions, or to create records to respond to a request.
Include a mailing address and a daytime telephone number so we can contact you if necessary. When submitting your request by mail, please mark the envelope "FREEDOM OF INFORMATION ACT REQUEST."
Note: Keep a copy of your request. You may need to refer to it in further correspondence with the agency.
Office of the Secretary
Bobbie Parsons
Immediate Office of the Secretary
Office of Management and Organization
U.S. Department of Commerce
14th and Constitution Avenue N.W.
Washington, D.C. 20230
Phone: 202-482-3707
Fax: 202-219-8979
BParsons@doc.gov
Sample FOIA Request Letter
Date
Freedom of Information Act Request
Agency Head or FOIA Officer
Name of agency or agency component
Address (see discussion above on whom to contact
Dear __________:
Under the Freedom of Information Act, 5 U.S.C. § 552, I am requesting copies of [identify the records as clearly and specifically as possible].
If there are any fees for searching or copying the records, please let me know before you fill my request. [Or, please supply the records without informing me of the cost if the fees do not exceed $______, which I agree to pay.]
If you deny all or any part of this request, please cite each specific exemption to think justify your withholding of information. Notify me of appeal procedures available under the law. Optional: If you have any questions about handling this request, you may telephone me at ___________ (home phone) or at ___________ (office phone).
Sincerely,
Name
Address
http://www.osec.doc.gov/omo/FOIA/foiarequest.htm