Methyl chloroform is an important part of the special penetrant process with many desirable characteristics, but it is also a 'severe ozone depletor'. It is still used for some advanced and special purposes which are scheduled for elimination in 2002 under the Montreal Protocol. For the replacement of methyl chloroform, the first potentially ozone-friendly chemical is HCFC-123. Here, vise capability factor is important for the applications of liquid penetrant tests, but it seems that methyl chloroform is still move suitable than HCFC-123 especially for application to shallow discontinuities. (C) 1997 Elsevier Science Ltd.