very unique and hard to find depression era antique american industrial single-sided die cut steel "be careful" safety first sign attributed to the burdick enamel sign co., chicago, ill. the dark cobalt blue porcelain enameled sign was salvaged from an old automotive assembly plant located in indiana. the heavy gauge steel sign contains a retains the original highly desirable cobalt blue porcelain or vitreous enameled finish with bright white lettering. the factory safety first" sign measures 20 x 9 inches.