The requirements for access to Sensitive Compartmented Information (SCI) include:

1. Having a Top Secret security clearance. This typically involves completing a Single Scope Background Investigation (SSBI) covering the past 10 years.
2. Being granted access on a strict "need-to-know" basis, meaning that access is only given if the individual requires the information to perform their job.
3. Being approved by the appropriate government authority that controls the specific SCI program or compartment.
4. Signing a non-disclosure agreement (NDA), specifically the SCI Nondisclosure Agreement (IC Form 4414), which legally restricts sharing the information.
5. Undergoing indoctrination or "read-in" to the SCI program and having access recorded.
6. Continuous personnel security and counterintelligence evaluations to maintain access eligibility.
7. Access to SCI must be conducted within specialized facilities known as Sensitive Compartmented Information Facilities (SCIFs) that meet strict physical security standards.

SCI is not itself a classification but information that is compartmented due to its sensitive intelligence nature. Access eligibility does not mean automatic access—explicit permission for each SCI compartment is required, and additional investigative measures such as polygraphs may be part of the process depending on the compartment.

To summarize: Access requires Top Secret clearance with a background check, need-to-know authorization, signing an NDA, approval by the appropriate authority, indoctrination, continuous evaluations, and handling within secure facilities.