By Colin Kellaher

Air Products & Chemicals Inc. on Thursday said it will build a $4.5 billion clean-energy complex in Louisiana, marking its biggest U.S. investment ever, as the world's transition to cleaner sources of energy continues to gain speed.

The Allentown, Pa., industrial gases company said the project would create 170 permanent jobs and would produce more than 750 million standard cubic feet of blue hydrogen a day.

"Blue" products are made using hydrocarbons as a feedstock, with the carbon dioxide in the production process captured for permanent sequestration.

Air Products said it will compress a portion of the blue hydrogen for supply to customers through its Gulf Coast hydrogen pipeline. The rest will be used to make blue ammonia that will be sent around the world and converted back to blue hydrogen for transportation and other markets.

Air Products said it expects the project will be operational in 2026.

Air Products in June unveiled plans to build a multi-billion-dollar hydrogen energy complex in Canada and last year said it was teaming with Saudi Arabia's ACWA Power to build a $5 billion green hydrogen-based ammonia-production facility powered by renewable energy in Neom, the $500 billion megacity being built in the kingdom.

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