  The study of group properties of the extremely metal-deficient gas-rich local
dwarfs is very promising for the understanding the galaxy formation process at
high redshifts. About 20 such objects have been picked up from the literature
in the recent review by Kunth & Ostlin(2000). However part of these galaxies
got low metallicity as a result of earlier observations, and can have rather
large uncertainties in their cited element abundances. Before to perform the
detailed studies of such galaxies as of some extreme group, it is useful to
revise their metallicities. We present the results of the SAO 6m telescope
spectrophotometry of two Blue Compact Galaxies (BCG) reported from earlier
studies as very metal-poor objects. Well measured [O III] line 4363 A allows to
deduce the temperature in HII regions and get reliable abundances of chemical
elements. For UM 133 we derive 12+log(O/H) = 7.63+/-0.02, coincident with the
published value. UM 382, according to our data, is significantly more
metal-rich: its 12+log(O/H) = 7.82+/-0.03 in comparison to the published value
7.45. The third galaxy, UM 283 seems have got its very low 12+log(O/H) = 7.59
due to a misprint. We used its published emission line intensities and derived
instead the value of 7.95. Thus the latter two galaxies should NOT be
considered as the extremely metal-poor BCGs.
