  To explain the nature of the anomalously high reddening (Av~10 mag) towards
one of the most luminous stars in the Galaxy - Cyg OB2 #12 (B5 Ia-0), also
known as MT304, we carried out spectro-photometric observations of 24 stars
located in its vicinity. We included five new B-stars to the members of Cygnus
OB2, and for five more photometrically selected stars we spectroscopically
confirmed their membership. We constructed the map of interstellar extinction
within 2.5 arcmin radius and found that interstellar extinction increases
towards MT304. The increase of reddening suggests that the reddening excess may
be caused by the circumstellar shell ejected by the star during its evolution.
We also report the detection of a second component of MT304, and discovery of
an even fainter third component, based on data of speckle interferometric
observations taken with the Russian 6-m telescope.
