Lead was used extensively in plumbing and is still therefore a concern for plumbers working with old buildings. As lead is no longer allowed to be used for potable water supply the best solution is to remove it and replace with copper, but this is not always practical or possible and there may be situations where a connection from an existing lead pipe to copper or plastic pipe needs to be made.
Lead-Loc is the market leader in lead pipe connector plumbing fittings specifically for this purpose.