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We point out the peculiarities of the line of sight of Q0302-003 which wasrecently used to estimate the He II opacity at $z \sim 3.285$. This line ofsight contains a large void in Lyman $\alpha$ clouds, in the region used forthe He II opacity observation, and the void is thought to be caused by theionizing radiation from a foreground quasar (Dobrzycki and Bechtold 1991). Ifthis is true, then the radiation from the foreground quasar is more relevant inthe region used for the estimation of the He II opacity than the diffuse UVbackground radiation. We argue that in that case the observed opacity shouldnot be used to put constraint on the diffuse UV background radiation. Using atypical spectral index of quasars, we estimate that most of the observed He IIopacity must be due to Gunn-Peterson effect and suggest a H I Gunn-Petersontest along this line of sight. We further discuss the clumpiness of theintergalactic medium in the vicinity of Q0302-003 as suggested by observations.Comment: To appear in MNRAS. uuencoded compressed postscript file (4 pages

On the interpretation of the Hen absorption in the line of sight of Q0302-003