A New York company and two utilities have a cost-effective solution to the nation’s aging underground infrastructure: a robot that crawls through cast-iron natural-gas pipelines and replaces their deteriorating joints, effectively renewing the pipes for up to 50 years.

The cast-iron sealing robot, or CISBOT, can crawl as far as 1,500 ft through a single 5-ft x 5-ft hole, eliminating the need to tear up streets every 12 ft to access the pipe’s joints. The operator-controlled CISBOT fills in the joints with an anaerobic sealant while the natural gas is still flowing through the pipes. The sealant, which has been lab-tested to show a life span of 50 years if applied by the robot, replaces jute, often sealed with lead, that had been used to fill the joints in the cast-iron pipes—many of which were installed at the turn of the 20th century.