The most important environmental factors are ultraviolet exposure and chemical exposure. In the absence of chemical compatibility concerns (determined by the UltraTech compatibility chart for PE products), the next most important factor for outdoor, polyethylene spill containment products will be ultraviolet irradiation (UV) exposure. The most important factors with reference to UV are thickness, UV Inhibitor (UVI) content, and pigment color, type, and concentration. Ultraviolet irradiation exposure causes molecular structure and bond changes that result in the embrittlement of PE. Very thin PE can become brittle and fracture in less than a year (think contractor’s PE Visqueen sheeting). Thicker parts take longer to break down. The addition of UV Inhibitors to the PE allows it to sustain more UV exposure without breaking down. Darker pigments, inorganic pigments, and higher concentrations of pigments also individually and collectively will give PE a longer life before appreciable UV damage occurs.