Phosgene (COCl₂)

Source/Presence:

Phosgene is used in the chemical industry as an intermediate product, for example in the production of plastics, polycarbonates, isocyanates, dyes, plant protection products, and active pharmaceutical ingredients.

Phosgene gas can be produced unintentionally when chlorinated solvents, chlorinated plastics, or other chlorinated substances are heated to high temperatures, burned, or decomposed.

Possible sources include welding operations, fires, thermal decomposition, chemical facilities, laboratories, production areas, metal processing, and hazardous materials storage facilities. In defective, overheated, or burning lithium-ion batteries, various toxic fire and decomposition gases can also form during thermal runaway; phosgene may be particularly relevant when chlorine-containing materials or substances are involved.

Therefore, appropriate applications for phosgene detection include, among others, law enforcement evidence rooms, battery warehouses, recycling facilities, operators of stationary battery storage systems, BESS facilities, solar farms with battery storage, grid operators, laboratories, and industrial facilities.

Limit values:

Due to its high acute toxicity, very low occupational exposure limits apply to phosgene.

In Germany, the occupational exposure limit is 0.1 ppm, or 0.41 mg/m³.

International guideline values are also in a very low ppm range.

Since phosgene can be hazardous even at low concentrations, air monitoring should not rely on smell, but rather on an appropriate phosgene sensor or technical gas detection.

Consequences:

Phosgene irritates the eyes, nose, throat, and respiratory tract and can cause serious damage to the lungs.

Possible symptoms include coughing, a burning sensation in the eyes and respiratory tract, chest tightness, difficulty breathing, headaches, nausea, or general discomfort.

It is particularly dangerous that severe symptoms may appear later on.

Pulmonary edema can develop even hours after exposure and, in severe cases, lead to respiratory failure or life-threatening poisoning.

Note:

Measurement is important because phosgene cannot be reliably detected by its odor, and its dangerous effects may not appear immediately.

A phosgene sensor helps detect phosgene early, monitor concentrations, and pinpoint possible sources.

Especially in evidence rooms, battery storage facilities, BESS installations, solar farms with battery storage, laboratories, production areas, and during fire or decomposition processes, measuring phosgene should be part of a comprehensive program for hazardous substance monitoring, gas detection, and air quality monitoring.