A sealed blister assembly is made tip of a blister sheet, a lid sheet, and a label sheet. The plastic sheet and plastic lid are joined together to form a substantially impermeable seal. The seal is formed by engagement of an undercut in the plastic sheet and a shoulder in the plastic lid. A plastic sheet and/or plastic lid are made from a polymer such as low density polyethylene to obtain the impermeable seal. The label sheet is secured directly to the blister and lid sheets.