Use of hydroquinone in polyurethane foams containing halogenated phosphate polyester additives

In a method of making polyurethane foam which has reduced combustibility characteristics wherein the polyurethane foam formulation contains a halogenated phosphate polyester additive having the formula ##STR3## wherein R is an aliphatic hydrocarbon having 1-8 atoms or an aromatic hydrocarbon radical having 6-14 carbon atoms,

• X is a halogen selected from chlorine, bromine and a mixture thereof,
• a is an integer of 0-4,
• n is an integer of 2-6, and
• each
• R' is a haloalkyl radical having 1-8 carbon atoms, the halogen in this radical being chlorine, bromine or a mixture thereof,
• wherein the improvement comprises:
• adding an effective amount of hydroquinone to inhibit scorching in said foam formulation.