Hydroquinone is safe! This ingredient is FDA approved and used by dermatologists worldwide to treat pigmentary issues.
It is only unsafe when used without proper doctor supervision and without knowledge of where it was sourced. Although there have been concerns about hydroquinone causing cancer, there have been zero reports of cancer in patients to this day. The reports of cancer was noted in the original study of hydroquinone when it was used in rat animals at very high doses.
If you are still concerned, you can switch to the non-HQ formulation such as The Spot Cream HQ Free and HQ Free+ or The Spot Peel Boost.