The Boring Company, a tunneling firm founded by Elon Musk, received a fine of about $500,000 for dumping wastewater at two sites across its Las Vegas project, Fortune reported.

Musk’s company wants to build a network of tunnels beneath cities to decrease traffic congestion. The company’s website mentions that it has received approval for 68 miles of tunnel and 104 stations for its Vegas Loop.

However, Clark County Water Reclamation District (CCWRD) reportedly caught the company dumping fluids and spoils into two manholes and two on-site cleanouts. A notice of violation cited by Fortune stated that the actions led to “substantial damage” and required water agency crews to clean 12 cubic yards of mud, spoils and solid waste from a sewage treatment facility.