For decades, telecom companies have known that lead in their networks posed risks to workers, and did little about it. Lead can cause a variety of ailments in adults, affecting the kidney, heart and reproductive systems, and it is classified as a probable human carcinogen. WSJ’s Shalini Ramachandran explains the danger of lead cables -- and what telephone companies knew. Further Reading: - America Is Wrapped in Miles of Toxic Lead Cables  - What AT&T and Verizon Knew About Toxic Lead Cables  -​​ Workers Exposed to Toxic Lead Cables Wrestle With the Aftermath  - How the Journal Investigated Hidden Lead Cables Circling the U.S.  Further Listening: - Part 1: America Is Wrapped in Toxic Lead Cables   Learn more about your ad choices. Visit megaphone.fm/adchoices