How to Inspect for Evidence of Workplace Mold

What Counts as Evidence of Workplace Mold?

Evidence of workplace mold includes visible growth, water damage indicators, musty odors, moisture readings, and documented health symptoms among occupants. According to OSHA workplace guidance, the most important initial step is a thorough visual inspection combined with systematic documentation of what you find.

The challenge is that mold often hides. It grows behind walls, under flooring, inside HVAC systems, and above ceiling tiles. But even when you cannot see mold directly, there are reliable indicators that trained inspectors and informed workers can identify and document.

Why Documenting Evidence Matters

When you suspect mold in your workplace, your documentation becomes the foundation for everything that follows: management response, professional assessment, remediation decisions, and—if symptoms develop—your medical care.

The CDC/NIOSH Action Steps guidance is clear: "Keep a record of when, where, and how much mold or water-damaged materials or areas are identified. Also record what has been done to fix underlying problems leading to the water damage."

This isn't bureaucratic paperwork. It's protection. Without documented evidence, workplace mold problems often go unaddressed, and workers experiencing health effects struggle to connect their symptoms to their environment.

The First 15 Minutes: Where to Look First

Before calling in professionals, conduct a systematic walkthrough of your workspace. Focus on these high-probability locations identified in the EPA's commercial building remediation guide:

Moisture-prone areas

• Bathrooms, break rooms, and any space with plumbing
• Areas below windows (condensation accumulation)
• Exterior walls, especially corners
• Ceiling tiles below the roof or upper floors

Hidden problem zones

• Pipe chases and utility tunnels with leaking or condensing pipes
• Condensate drain pans inside air handling units
• Porous thermal or acoustic liners inside ductwork
• Roof materials above ceiling tiles

Water damage history spots

• Areas where leaks or flooding previously occurred
• Spots where repairs were made but problems may have returned
• Zones with visible staining, peeling paint, or discoloration

"Mold can grow in hidden areas such as behind walls, under floors, or in HVAC systems. This makes detection and remediation challenging and often requires professional intervention," notes Chris Kushmaul, a water damage and restoration specialist.

What to Document: Your Evidence Checklist

The CDC/NIOSH Dampness and Mold Assessment Tool (DMAT) provides a standardized approach to documenting what you find. For each area of concern, record:

Visual indicators

• Visible mold: patches or spots colored differently than underlying material (typically gray, brown, or black), fuzzy texture
• Water damage signs: peeling paint, efflorescence (white crystalline deposits), rust stains, warping, deteriorated or crumbling materials
• Staining patterns: water marks on ceiling tiles, walls, or flooring

Size documentation

Use the DMAT scoring system for consistency:

• Small: equal to or smaller than a sheet of paper (8.5 x 11 inches)
• Medium: larger than paper but smaller than a standard door (32 x 80 inches)
• Large: bigger than a standard door

Sensory evidence

• Musty or earthy odors, even without visible mold
• Humidity or dampness that feels excessive
• Condensation on surfaces

Instrument readings (if available)

"The moisture meter is the most important tool at our disposal when it comes to detecting moisture behind or below the surface of walls, floors, ceilings, shower tiles and structural components," explains Sean Moss, Certified Indoor Environmental Consultant at Mold Insight Inc.

If you have access to inspection tools, document moisture meter readings, relative humidity measurements, and any infrared camera findings showing temperature differentials that suggest hidden moisture.

The 48-Hour Window: Why Speed Matters

One of the most consistent findings across OSHA, EPA, and NIOSH guidance is the critical 24-48 hour window. Damp or wet building materials must be cleaned and dried within this timeframe to prevent mold growth.

This means two things for your documentation:

If water damage just occurred, your evidence collection is also a race against time. Document immediately, report immediately, and advocate for immediate response.

If water damage is ongoing or historical, the window has likely closed and mold growth is probable. Your documentation should note how long conditions have persisted and any delays in response.

When Mold Is Hidden: Documenting Indirect Evidence

You may suspect hidden mold if a building smells moldy but you cannot see the source, or if you know there has been water damage and occupants are reporting health problems. The EPA guidance explicitly acknowledges this scenario.

Indirect evidence worth documenting includes:

• Persistent musty odors without visible source
• History of water intrusion or flooding
• Patterns of health symptoms among occupants
• HVAC system concerns (unusual smells from vents, visible debris)
• Prior repairs for water damage that may have been incomplete

This documentation provides the basis for professional investigation, which may include air sampling, surface sampling, or invasive inspection of wall cavities and concealed spaces.

Connecting Workplace Exposure to Health

Research increasingly confirms what affected workers experience: indoor mold exposure causes real health effects. A 2024 meta-analysis published in PMC found that living or working in mouldy environments increases asthma risk by 53%.

If you or coworkers are experiencing symptoms that worsen at work and improve away from the building, document this pattern. Note:

• Which symptoms occur (respiratory issues, headaches, fatigue, cognitive difficulties)
• When symptoms started and whether they correlate with known water damage events
• Whether multiple occupants report similar experiences
• Whether symptoms improve on weekends, vacations, or when working remotely

This symptom documentation, combined with environmental evidence, helps your provider understand the full picture. For individuals with genetic susceptibility to biotoxin illness, even "normal" levels of mold exposure can trigger significant inflammatory responses. Learn more about signs that indicate mold exposure and how to work with a CIRS-specialized provider.

Next Steps: From Documentation to Action

Once you have gathered evidence, the path forward depends on what you find:

For visible mold or active water damage, report to building management immediately with your documentation. Reference the OSHA guidance that moisture problems must be addressed within 24-48 hours.

For suspected hidden mold, request professional environmental assessment. Your documentation provides the starting point for their investigation.

For persistent health symptoms, consult a provider who understands mold-related illness. The $99 starter panel can help identify whether biotoxin exposure is affecting your health—delivered directly to your door, with results reviewed by a CIRS-specialized provider.

Key Takeaways

• Visual inspection is the most important first step—document what you see, smell, and measure
• Use the DMAT size categories to standardize your descriptions
• The 24-48 hour window for preventing mold growth means speed matters for both response and documentation
• Hidden mold still leaves evidence: odors, moisture readings, staining, and symptom patterns
• Your documentation protects you and supports professional assessment and medical care

Related Resources

• Learn more in our comprehensive mold inspection and detection guide
• Understand what mold actually smells like and why musty odor is evidence
• Explore signs of mold exposure to understand symptom patterns

Medical Disclaimer

This article is for educational purposes only and does not constitute medical advice. Individual health responses to mold exposure vary based on genetic factors, exposure duration, and overall health status. If you are experiencing symptoms, consult a healthcare provider familiar with mold-related illness. Environmental assessments should be conducted by qualified professionals. Individual results from testing and treatment vary.