By Colin Kellaher 



  Air Liquide SA on Tuesday said it signed a long-term agreement to supply gaseous oxygen, nitrogen and argon to Steel Dynamics Inc.'s planned $1.9 billion steel mill in Sinton, Texas. 


  The Paris gas supplier said it plans to invest more than $100 million in its U.S. Gulf Coast pipeline network to support the agreement. 


  Air Liquide said it will install an air-separation unit on the network in Ingleside, Texas, and extend the network by about 30 miles to the Sinton plant, which is slated for startup in mid-2021. 


  Write to Colin Kellaher at colin.kellaher@wsj.com