The minimum strains required to cause cracking of polycarbonate upon exposure to several windshield washer fluids were determined. A detailed investigation of this environmental stress cracking was conducted with one of these fluids which is identified here as fluid A. This detailed investigation included determinations of cracking strains for polycarbonate upon exposure to the fluid's components and several nonionic surfactants. Critical strain determinations for polycarbonate exposed to the liquid components indicate that both monoethanolamine and surfactants are stress cracking agents for polycarbonate. Cracking strains were also determined for a polycarbonate/acrylic blend upon exposure to fluid A and were shown to be significantly greater than those obtained for pure polycarbonate. However, both materials stress crack in splash tests.