the tier 3 investigation is designated for the following positions

Tier 3 investigations are used for federal positions that require eligibility for access to Secret (or “L”) level classified information and are generally designated as non‑critical sensitive positions.
What Tier 3 Is For
- Tier 3 is the standard background investigation for positions that require eligibility for access to Secret classified information (including DOE “L” access).
- These positions are typically designated non‑critical sensitive, as opposed to critical‑sensitive or special‑sensitive roles which require higher tiers.
Positions That Use Tier 3
Common position designations that call for a Tier 3 investigation include:
- Federal civilian or contractor roles that need Secret clearance to perform official duties.
- Non‑critical sensitive positions with duties that involve access to or control of Secret national security information, systems, or facilities.
How It Fits With Other Tiers
- Positions needing Top Secret/SCI access (critical‑ or special‑sensitive) require Tier 5, not Tier 3.
- Non‑sensitive Public Trust positions (moderate or high risk) instead use Tier 2 or Tier 4 investigations, since they do not require classified access.
In short, the Tier 3 investigation is designated for non‑critical sensitive national security positions that require Secret‑level (or “L”) access eligibility, but not Top Secret or SCI access.