A resin composition and an article formed therefrom are disclosed. The resin composition comprises a halogenated polyol, a brominated polyol different from the halogenated polyol, and a flame retardant. The resin composition may further comprise other components, such as supplemental polyols, catalysts, adhesion promoters, surfactants, blowing agents, additives, or combinations thereof. The article comprises the reaction product of an isocyanate, the halogenated polyol, and the brominated polyol in the presence of the flame retardant, a blowing agent, and optionally, one of more of the other components. Typically, the article is defined as a polyurethane foam. The article exceeds Class I flammability requirements, such as flame spread index, smoke density, and convective flame spread parameter according to ASTM E-84 and FM 4880 testing. In addition, the article exhibits excellent dimensional stability and adhesion strength, and may be used to form building materials, such as insulation, wall, and ceiling panels.