The Environmental Protection Agency sent letters requesting telecom companies to meet with the agency about their lead-sheathed phone cables, in a new phase of an investigation in the EPA’s efforts to protect the public from potential lead hazards.

The agency’s move comes on the heels of the EPA finding more than 100 soil and sediment readings with lead above the regulator’s safety guideline for children at some phone lead-cable sites identified by The Wall Street Journal in three states.