Extrinsic criteria

Safety, health concerns (represented in this context as toxicity), and environmental impact are a third class of criteria in assessing the suitability of a reagent selected on the basis of the above chemical criteria. These extrinsic criteria are inextricably linked with the laboratory equipment and the infrastructure of the place of work. This may mean that a specific reagent can be used without any problem in labo- 

A regulation indicating the maximum permissible airborne concentration of a dangerous compound in a place of work over 8 hours a day is enforced on the basis of threshold limiting values (TLVs). These are collected in lists and a selection of TLVs of phosgenation reagents is given in Table 3.4 in Chapter 3. 

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