AT&T’s share value took a nose-dive on Friday amid growing concerns among investors about the company’s lackluster performance and a potentially costly lead contamination cleanup.

The telecom giant opened on July 18 at a three-decade-low of $13.53 — an over 8% drop in five days.

This massive slip in valuation was triggered by a story broken by The Wall Street Journal and covered by The Dallas Express last week.

It revealed that successors of the Bell System, a telecommunications network that dominated the American market until its breakup by the government in the 1980s, inherited a massive network of lead-covered cables, which continue to pose the risk of lead exposure to workers, the public, and the environment.

These successors include current power players in the telecom market such as AT&T and Verizon.

The financial markets took note of the risk exposure for AT&T, which might soon face a high-cost cleanup of lead contamination across its nationwide network that includes 40% of U.S. homes, according to The Dallas Morning News.

AT&T said in a statement to the WSJ that its legacy cables “are maintained in compliance with applicable environmental, health, and safety rules, consistent with our approach for all our infrastructure.”

A spokesperson for the trade association U.S. Telecoms similarly responded to the WSJ report by saying, “We have not seen, nor have regulators identified, evidence that legacy lead-sheathed telecom cables are a leading cause of lead exposure or the cause of a public health issue,” according to Reuters.

It is unclear whether telecom companies running on former Bell systems can be held legally liable for any lead contamination.

“We have discussed the copper lead sheathing situation with many industry contacts and have been unable to find a reasonable way to calculate any potential liability,” a note from JPMorgan analysts read, according to Reuters.

As Michael Hodel, an analyst with Morningstar Investment Research, explained, the “situation warrants watching” but “we don’t expect the telecom industry will bear substantial legal liability,” according to Reuters.

Nevertheless, for investors, the uncertainty over the lead contamination issue has snowballed with other concerns over AT&T’s financial health.

Earlier this year, AT&T reported a disappointing $1 billion in free cash flow, a miss from the anticipated target of $3 billion, according to the DMN. This shortfall raised red flags over the firm’s ability to pay off some of its heavy debt and maintain dividend payments for the second consecutive year.

The company also recently disclosed that it anticipated weak wireless subscriber growth in Q2, according to Seeking Alpha.

Yet AT&T is not the only telecom company suffering in terms of stock valuation since the WSJ report.

Verizon has seen share prices slump by approximately 10% since Friday, opening at $31.46 on July 18 compared to $35.19 on July 12.

Lumen Technologies has similarly skidded from $2.13 on July 12 to $1.70 at opening on July 18.