Fumigation Safety, Personal Protective Equipment, and Emergency Response
Respiratory protection logic
Air-purifying respirators may only be used where the contaminant is known, the concentration is below the cartridge's protection limit, and oxygen is adequate. For entry into a fumigated structure, unknown concentrations, or any IDLH atmosphere, use pressure-demand SCBA or supplied-air with escape cylinder. Every respirator user needs a medical evaluation, annual fit testing, and training before use.
Air monitoring and the buddy system
Thermal-conductivity meters are non-specific and can be fooled by carbon dioxide or moisture; colorimetric tubes and electronic sensors have cross-sensitivities and need calibration and bump tests. Never enter alone: use a two-person rule with an outside observer, continuous communication, and a pre-briefed rescue plan. Placards at every entrance, barriers, and a visible tarp watch are part of the control set that keeps the public out.
Emergency response
Recognize early exposure: headache, dizziness, nausea, blurred vision, irritation. Remove the person to fresh air only if you can do so without becoming a casualty; call 911 and poison control; bring the label and SDS. Do not induce vomiting after ingestion unless directed. Decontaminate clothing and skin with soap and water. Report the incident per label and state requirements.
Traps
Believing a cartridge respirator is acceptable "for a quick check"; removing PPE because the meter reads zero on an uncalibrated device; forgetting that rescue attempts cause responder fatalities; and overlooking that PPE in the label table is mandatory, not advisory.
Rule of thumb: if you cannot state the concentration and the oxygen level, you are in an IDLH atmosphere - SCBA only, or do not enter.