underground sewer tunnel

 In many sewer systems, organic decomposition and stagnant conditions can lead to a sudden buildup of carbon dioxide and hydrogen sulfide, while simultaneously displacing oxygen to dangerous levels.

2026-00133    HUGO      LAVIN DIAZ    55   meth
2026-00132    SHERMIRA  MISTERKA      33   co2, meth, pcp
2026-00131    ANGEL     SUMLER        43   co2, meth, h2s

Angel Sumler (meth + CO₂ + H₂S) most plausibly entered the worst air zone first, where hydrogen sulfide and carbon dioxide had accumulated and oxygen was lowest. She likely collapsed quickly at or near the source of the toxic atmosphere and remained there. Her toxicology reflects direct exposure to sewer gases in the most concentrated area.

Shermira Misterka (meth + PCP + CO₂) entered into the same contaminated pocket as Angel, possibly drawn in by concern or interaction with her. Being intoxicated with PCP could have impaired her judgment, perception, and risk awareness, making it more likely she entered deeper than a sober person would, failed to recognize danger cues, or delayed retreat. She encountered oxygen depletion and CO₂ buildup, but not necessarily the same high H₂S pocket as Angel.

Hugo Lavin Diaz (meth only) most plausibly either entered but did not reach the deepest contaminated zone, or was exposed primarily to low oxygen / general tunnel atmosphere collapse conditions rather than the concentrated gas pocket. That’s why he showed no CO₂ or H₂S signature —suggesting either a different location within the tunnel system or a different exposure duration/pattern.