ICA Fluor, a joint venture between engineering and construction firm Fluor and Mexico’s largest infrastructure company ICA, is to build a $1 billion refining facility in Mexico.

Fluor said on Monday that Pemex, the national oil company of Mexico, gave the green light for the engineering, procurement and construction (Phase II) of an expansion project at the Madero Refinery in Tamaulipas, in the northeast of the country. Fluor’s share of the contract is $500 million.

The Madero Clean Diesel project is part of Pemex’s modernization program and is designed to increase Mexico’s production of ultra-low sulfur diesel.

“We are very pleased with the performance of ICA Fluor, and this award by Pemex demonstrates the trust and confidence in our joint venture to successfully execute this very significant clean fuels project at the Madero refinery,” Fluor’s chief operating officer Peter Oosterveer said in a statement. “Fluor and ICA Fluor remain fully committed to Pemex and our other clients in the Mexican market.”

Under the contract ICA Fluor will provide detailed engineering, procurement, construction, commissioning and start-up services for two 25,000-barrel-per-day diesel hydrodesulfurization trains and associated facilities at the refinery. The project also includes revamping the existing diesel unit and installing new hydrogen, sulfur recovery and water treatment plants.

The project is expected to be completed in the first quarter of 2018.