Cylindrical double-wall tanks from Assmann Corporation eliminate chemical spills and prevent dome collapse without the expense of lined concrete containment. Assmann’s molding process provides a heavier-top sidewall and dome to prevent dome collapse, while the primary inner tank and a secondary locked on outer tank ensures against chemical spills. Constructed of molded high-density cross-linked polyethylene or FDA compliant linear polyethylene, the double-wall tanks provide an outer shell containment that equals 120 percent of primary tank capacities, which exceeds EPA standards. The dome on the inner tank interlocks with the outer tanks’ sidewall, sealing the secondary containment area and preventing debris and snow from entering, making the system ideal for outdoor storage. The double wall design also prevents cross contamination of contents, eliminating the possible danger of commingling of reactive chemicals. The portable tanks provide a small footprint and are available in sizes ranging from 20 to 6,550 US gallons (2082-24794 liters). Lifting lug assemblies that are designed to hold up to twice the empty tanks weight are standard. Optional equipment includes heat tracing and insulation used with temperature sensitive chemicals. Other options include seismic restraint, wind load restraint, ultrasonic level device, reverse float level device, leak detection system, high-low level alarms, ladders, top discharge with foot-check valve, manways and bottom outlets.