Denver Airport -- The D-40 Level: Claims of Deep Underground Facilities

Denver Airport -- The D-40 Level: Claims of Deep Underground Facilities

The Specific Claim

Among the more specific underground facility claims circulating about Denver International Airport is the existence of a "D-40" or "D-50" level -- an alleged deep underground floor or complex extending 40 or 50 feet (or in some versions, floors) below the airport's acknowledged underground infrastructure.

This claim adds specificity to the general bunker theory by providing a specific designation that sounds official ("D-40" sounds like an engineering drawing designation) and a specific depth that places it well below anything in the public construction record.

Physical Constraints

Whether a deep underground complex is physically possible beneath the DEN site involves several factors:

Geology: The DEN site sits on the western edge of the Great Plains, on Pierre Shale -- a marine sedimentary formation consisting primarily of dark grey shale. Pierre Shale:

• Is not particularly hard rock; it is a relatively soft, fine-grained sedimentary rock
• Contains swelling clays (montmorillonite) that expand significantly when wet -- a significant engineering challenge for underground construction
• Has been associated with foundation problems in construction across the Denver metropolitan area
• Would require extensive liner and waterproofing systems for any habitable underground space

Groundwater: The water table beneath the DEN site is within a depth that would affect deep underground construction, requiring continuous dewatering systems for any occupied facility.

Construction evidence: Large-scale underground construction leaves surface traces: spoil (excavated material) that must be disposed of; ventilation structures; access points; power and utility infrastructure. The claimed D-40 level would require spoil disposal and utility infrastructure that would be visible at the surface and documented in construction records.

Why the Claim Persists

The "D-40" designation persists because:

• It sounds specific and official -- more credible than a vague "secret underground levels"
• No authoritative source can definitively prove there is no D-40 level (proving a negative is difficult)
• The airport's tour program only covers acknowledged areas; restricted areas provide the imagination with scope
• Phil Schneider's claimed engineering credentials lent the specific depth claim apparent professional authority