The Environmental Protection Agency estimates some 40 million Americans are exposed to drinking water containing lead above the acceptable level of 20 parts per billion.

A new federal law prohibiting the use of lead solder to join pipe in plumbing for potable water systems has resulted in a new product category-- solders that do not rely on lead.One such solder contains tin, copper and a small percentage of silver -- the same three elements as in dental fillings. According to Englehard Corp., which introduced the product, "Silvabrite 100," in addition to being safer, the new solders are generally stronger and more corrosion resistant.

The ban applies to all drinking water systems built after June 19, 1988. Homes built with lead solder systems will not be eligible for FHA and VA mortgage loans.