Endotoxins are lipopolysaccharide components from the cell walls of gram-negative bacteria. When these bacteria die in water-damaged environments, endotoxins are released into the air and dust, triggering inflammation upon inhalation or ingestion.


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In genetically predisposed individuals, endotoxins act as biotoxins that perpetuate the chronic inflammatory cascades characteristic of CIRS — especially in the brain, where they can contribute to neuronal injury and gray matter loss.

Endotoxins are prevalent in environments with organic material and moisture — like sewer lines, plumbing leaks, and drainage systems — leading to airborne endotoxin contamination. Even small plumbing breaches or dry p-traps can allow sewer gas — laden with endotoxins — to enter indoor air.

  • Endotoxins provoke strong inflammatory responses (e.g., TGF‑β1, MMP‑9, C4a), especially in HLA-susceptible individuals.
  • They can contribute to brain inflammation, volumetric decline, and neurological symptoms in CIRS.
  • Case studies relate severe neurological outcomes—even cortical atrophy—to chronic endotoxin exposure in water‑damaged environments.

A simple plumber smoke test (introducing tracer smoke into plumbing/p-traps) can reveal leaks or dry traps that allow sewer gas into living spaces. Once the leak is located through visual detection of escaping smoke, repairs can be made to eliminate ongoing exposure.

  • EnviroBiomics offers specialized ENDO (Endotoxin LAL) tests and combined panels.
  • These tests assess both mold DNA and endotoxin presence in environmental samples.
  • Testing provides an objective measure of endotoxin burden, especially when paired with mold metrics.

  1. Screen: Order an Endotoxin Dust Test through EnviroBiomics to quantify mold and endotoxins.
  2. Leak Detection: Conduct a plumber smoke test in suspect areas (bathrooms, kitchen, basement) to identify plumbing/ventilation breaches.
  3. Repair: Seal or repair identified leaks/traps to eliminate sewer gas ingress.
  4. Validate: Post-repair, retest with EnviroBiomics to confirm reduced endotoxin levels.
  5. Support: Pair environmental remediation with Shoemaker Protocol interventions (e.g., VIP, NeuroQuant monitoring).

Link: Endotoxin Dust Test