Compositions comprising at least one decontaminating agent, and being in a form of a gel, are disclosed herein, as well as processes for producing the compositions by contacting a solution containing the decontaminating agent(s) with at least one gelling agent. The compositions are useful in decontamination. The decontamination efficacy of the compositions can be enhanced by adding a solid hypochlorite salt to the composition. Systems are further disclosed herein which are designed for mixing the decontaminating agent(s) with the gelling agent(s) when and where needed, and for propelling the mixed solutions onto a surface to be contaminated. Methods employing the compositions for decontamination are also disclosed.