Why specific assessment is needed
Dichloromethane’s ready evaporation can produce substantial concentrations during open operations. Absence of the typical flammability of other solvents does not imply toxicological safety. The product, its concentration and every operation, including application, removal, cleaning and waste, must be identified before deciding whether existing measures are sufficient.
Effects on the body
NIOSH describes drowsiness, dizziness, irritation and effects on the nervous and cardiovascular systems. ILO/WHO warns that it can cause carbon monoxide poisoning and that high exposures may cause unconsciousness or death, with delayed effects. It also records carcinogenicity concerns. This combination prevents it being treated merely as an odour nuisance.
Small spaces and open surfaces
Application over a large surface increases evaporation. In a poorly ventilated enclosure or low-lying area, exposure can rise rapidly. Assessment should cover the entire space, nearby people and evacuation, not just the person applying the product. Opening a window does not by itself provide technical justification for control.
Substitution and containment
Substitution of the solvent or procedure should be considered, comparing the alternative’s hazards. If use continues, containment and extraction suitable for the task are needed. Glove and respiratory protection choices require dichloromethane-specific data: the usual selection for other organic vapours may be inadequate.
Heat, incompatibilities and emergencies
Contact with intense heat can generate hazardous decomposition products, so hot work and nearby hot surfaces must be reviewed. A spill or an unconscious person in an accumulation area requires emergency response. Improvised rescue should not be attempted, nor should an area be declared safe solely because liquid is no longer visible.
Prevention decision example
In a hypothetical example, an open cleaning operation is replaced with a less hazardous, contained method. Review checks that the new product does not introduce another major risk and that the work’s technical quality remains sufficient. Procedure, training and waste arrangements are updated. Improvement is documented through exposure conditions, not only a perceived reduction in smell.
