Softimage Xsi: final gathering and particles

When I render out a scene with particles (smoke from sphere) It screws up the lighting for the scene how can I fix this.

What shader do you have on particles?

FG may radiate from it that's why the lighting may be different.
A solution would be to remove the Final Gathering Caster option from your particles in the Visibility/Rendering properties window.
Hope it helps.

Cheers!