A SCIF is a Sensitive Compartmented Information Facility, and is mandated for use in some situations when reviewing classified and sensitive materials. If a President has cause, e.g. knows a Congressman has a known history of leaking classified material, can they ban that member of Congress from accessing all SCIFs?
In principle, perhaps, though it seems it would likely require an executive order. In practice, it would be an immense violation of longstanding protocol, and in particular if the congressperson was on any committee with a professional interest in the material (including oversight materials) then it would likely be a violation of the constitutional separation of powers. The following is from the Security Clearance Process FAQ of the Congressional Research Service:
Are Constitutional Officers (e.g., the President, Members of Congress) Required to Hold a Security Clearance to Access Classified Information?
Security clearances are not mandated for the President, Vice President, Members of Congress, Supreme Court Justices, or other constitutional officers. The criteria for election or appointment to these positions are specified in the U.S. Constitution, and except by constitutional amendment, no additional criteria (e.g., holding a security clearance) may be required. (18) Further, “by tradition and practice, United States officials who hold positions prescribed by the Constitution of the United States are deemed to meet the standards of trustworthiness for eligibility for access to classified information.” (19) Additionally, as Commander-in-Chief, the President has the authority to establish the standards for access to classified national security information. This authority is typically exercised through the issuance of executive orders. Executive Order 13467, which covers suitability checks and security clearances for federal employees, applicants, and contractors, includes a determination of which executive branch individuals are covered and which are exempted
The footnotes read as follows:
(18) For example, qualifications for Members of Congress may be found in Article I, Section 2, clause 2, of the U.S. Constitution, and qualifications for President may be found in Article II, Section 1, clause 5. Also see Powell v. McCormack, 395 U.S. 486 (1969).
(19) Information Security Oversight Office (ISOO), Classified Information Nondisclosure Agreement (Standard Form 312) Briefing Booklet, Spring 2001, p. 66, at http://www.archives.gov/isoo/training/standard-form-312.pdf. ISOO notes, however, that Members of Congress, as constitutionally elected officials, are not exempt from the “need-toknow” requirement, and might not have unlimited access to all classified information if such access is not required. Instead, ISOO writes that “[Members] are not inherently authorized to receive all classified information, but agencies provide access as is necessary for Congress to perform its legislative functions, for example, to members of a committee or subcommittee that oversees classified executive branch programs.”
So you're both right... or both wrong... The responsible parties who first generate classified documents may release the documents they generate, but not ones of other branches. While Congress can produce it's own classified documents and both executive and legislature can share and use each others classified documents in the creation of their own classified documents, they may not release any information from documents they did not generate. That means that the President may classified documents about Military Helicopter specs, he may not release documents about the budget for those helicopters because the budget was set by congress (if the specs have dollar signs on them, he'll need to to make sure they get redacted before release). Similarly, Congress may release closed-door testimony heard with respect to the Kennedy assassination by an investigative sub-committee, but they cannot release the documents still classified by the FBI.
With that out of the way, blocking access to a SCIF depends more on the classification level of the particular SCIF in question. If a congressman has only secret level access, they may not access a Secret level document in a Top Secrete level SCIF even if a congressman with Top Secret access could access a Secret level document in a TOP Secret level SCIF. This is largely to do with the fact that you can view any document in any SCIF rated at that classification level or lower. If you're clearance doesn't grant you access to higher levels, you can't get in (even though you may certainly read it if you're allowed in).
Additionally, all classified information is compartmentalized, so it's not enough to meet the the levels, but you need to be read into a compartmentlization before accessing any information on it, even if the classification would grant you access. This determination is called "Need to Know" and means that really, you should only have access to information in so far as not having it will be detrimental to doing your job. In practice, it means that if a Chair of the comittee on agriculture has Top Secret access, he'll get access on every dark ops farming program conducted by the United States... but not access to Area 51 reports of their experiments with flying saucers (assumed) because what do UFOs have to do with Farming (Okay, so he gets the reports on extraterrestrial cattle rustling... Roswell maybe as the crash was on a farm... but generally, no, he doesn't need to see reverse engineering of craft or diplomatic notes on the lizard people's demands from this week).
Additionally the President can only ban Congress people from Executive controlled SCIFs, not legislative SCIFs. The problem for Congress is location, because the nearest SCIF to their office in the Capitol Building... is in the West Wing... so it's not that the President can ban them from any SCIF... just that he can ban them from the nearest SCIF they can go to... cause it's in his office (I think Congress has a non-TS level SCIF) and he can ban them from seeing his classified information without unless they make a specific oversight request relevant to their committees areas of oversight. No one from Congress is allowed to waltz into the White House and peruse the classified docs for curiosity's sake.