35. Every drain situated in a place where residual hazardous materials are stored shall be(1) tightly blocked off at all times to prevent the discharge of materials; or
(2) connected to a system which, as the case may be, will ensure the discharge of materials into a system able to ensure their recovery. In the case of liquid materials, the system shall be able to hold the greater of the following volumes: 25% of the total capacity of all the stored vessels and 125% of the capacity of the largest vessel.
Notwithstanding the foregoing, this section shall not be applicable where vessels are placed in a basin able to hold the greater of the following volumes: 25% of the total capacity of all the vessels and 125% of the capacity of the largest vessel.