Thieves in Dallas are targeting utility lines in order to steal copper.

Damaged lines, presumed to have been caused by copper thieves, resulted in internet and landline phone outages at roughly 300 Oak Cliff households late Wednesday. AT&T told residents it could take up to half a day to restore connectivity.

Copper theft is a rising trend nationwide, a trend that the FBI deems a threat to U.S. infrastructure, per its website:

“Copper thieves are threatening US critical infrastructure by targeting electrical substations, cellular towers, telephone land lines, railroads, water wells, construction sites, and vacant homes for lucrative profits. Copper thefts from these targets have increased since 2006; and they are currently disrupting the flow of electricity, telecommunications, transportation, water supply, heating, and security and emergency services, and present a risk to both public safety and national security.”

The Dallas Police Department (DPD) backed up the FBI’s assessment in a statement to The Dallas Express.

“Stolen metals can be resold by thieves. The value of scrap metal is determined by the market and buyers such as recycling companies and scrap yards,” stated a DPD public information officer.

The value of stolen copper has turned into big business in the United States. Estimates show that the illicit-copper industry tops $1 billion a year in damages, and Texas lawmakers upgraded penalties for theft of bronze, brass, and copper in 2010.

Criminals convicted of stealing these precious metals now face legal penalties that include incarceration for up to two years and a fine of up to $20,000.

According to Dallas City data, there had been 6,317 different reported thefts year-to-date as of Wednesday, excluding motor vehicle thefts.

The DPD public information officer told The Dallas Express that “the Dallas Police Department has not seen an increase [in] reports of copper thefts.”

The Dallas Express contacted Dallas District Attorney John Creuzot’s office to inquire about metal theft in Dallas County but did not receive a response by the time of this article’s publication.