they stopped using lead solder in plumbing on june 7, 1991.
when did they stop using lead solder in plumbing?
june 7, 1991
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in the united states, lead is prohibited in solder and flux in plumbing applications for drinking water use, per the safe drinking water act (sdwa). historically, a higher proportion of lead was used, commonly 50/50. this had the advantage of making the alloy solidify more slowly. with the pipes being physically fitted together before soldering, the solder could be wiped over the joint to ensure water tightness. although lead water pipes were displaced by copper when the significance of lead poisoning began to be fully appreciated, lead solder was still used until the 1980s because it was thought that the amount of lead that could leach into water from the solder was negligible from a properly soldered joint. the electrochemical couple of copper and lead promotes corrosion of the lead and tin. tin, however, is protected by insoluble oxide. since even small amounts of lead have been found detrimental to health, lead in plumbing solder was replaced by silver (food-grade applications) or antimony, with copper often added, and the proportion of tin was increased (see lead-free solder.)
solder