In Zickgraf et al. 1989 (A&A, 220, 206) there is a comment on the density of the disk around the supergiant LHA 115-S 18. In Table 1 they provide (following Waters 1986) the mean particle density at r=R* for a number of sources: 3.2 x 1012, 2.6 x 1012, 4.6 x 1012, 1.7 x 1012 cm-3 for sources S 18, S 12, S 134, and R 126, respectively. Having calculated a maximum disk radius of 300R*, they calculate a mean density of few 109 cm-3. These values are consistent with both estimates from IR emission and by McGregor et al. (1988), who independently found densities of about 109 cm-3 from the CO first overtone emission in S 12, S 134, and R 66.