I'm not sure this is going to end well for telecom companies.
It's one thing to have rolled-out miles and miles of cables during the past century and only now discover that the material you used is toxic to residents. That sort of discovery happens every day as new studies are conducted. However it's quite a different thing if you've known this danger for years and didn't do anything to notify people or mitigate the risk. That's negligence and a heaping helping of liability on your hands.
First things first, mitigate the risk to health and safety and pull out the cables if that's what is needed. That's going to be an expensive proposition -- especially if it means tearing up roads and existing infrastructure to get at the buried cables.
(This links to an article in The Wall Street Journal. It's supposed to be a free article without needing a subscription. If you try to access the link and it blocks you let me know. I'll send you a PDF of the story.)
Lead levels in sediment and soil at more than four dozen locations tested by the Journal exceeded safety recommendations set by the U.S. Environmental Protection Agency. At the New Iberia fishing spot, lead leaching into the sediment near a cable in June 2022 measured 14.5 times the EPA threshold for areas where children play. “We’ve been fishing here since we were kids,” said Tyrin Jones, 27 years old, who grew up a few blocks away. For many years, telecom companies have known about the lead-covered cables and the potential risks of exposure to their workers, according to documents and interviews with former employees. They were also aware that lead was potentially leaching into the environment, but haven’t meaningfully acted on potential health risks to the surrounding communities or made efforts to monitor the cables.