The present invention provides for an integrated valve regulator assembly that comprises an integral body having a base portion that includes an axis for mounting on and coaxially with the neck portion of a pressurized source vessel and an assembly outlet, a defined internal passage in the integral body that extends through and between the base portion of the integral body and the assembly outlet, a sub-atmospheric pressure regulator assembled within the integral body of the integrated valve regulator assembly, an isolation valve positioned within the defined internal passage of the integral body and located downstream from and in communication with the sub-atmospheric pressure regulator, and a filling port disposed between the axis for mounting on and coaxially with the neck portion of the pressurized source vessel and the sub-atmospheric pressure regulator. The present invention further provides for a system for the controlled storage and dispensing of a hazardous material at sub-atmospheric pressure that comprises a pressurized source vessel and the integrated valve regulator assembly of the present invention. The present invention further provides for an additional integrated valve regulator assembly as described with the exception that the pressure regulator utilized is for super-atmospheric pressure conditions and also a system that comprises a pressurized source vessel and the integrated valve regulator assembly that includes a super-atmospheric pressure regulator.