Shell Chemical Appalachia LLC has reached a settlement with environmental groups, agreeing to implement more safeguards to monitor air quality at the site of its multi-billion dollar ethane cracker that is under construction in western Pennsylvania.

The company signed a settlement with the Clean Air Council and the Environmental Integrity Project to operate a fenceline monitoring program in addition to the facility’s other plans for air monitoring. It would also conduct flare testing to ensure that equipment is destroying nearly all pollutants emitted.

“Fenceline monitoring is a critical tool that allows nearby community members and the plant’s workers to feel confident that the plant is operating pursuant to its permit terms,” CAC Executive Director Joseph Otis Minott. “Residents being asked to host large industrial facilities have a right to be assured that the plant is meeting its legal requirements.”

After more than a year of review, the Pennsylvania Department of Environmental Protection issued Shell an air permit for the facility in June 2015. Two months later, the environmental groups filed an appeal of that permit with the state Environmental Hearing Board. The groups pushed for the fenceline monitoring program and stronger permit requirements for flare control efficiency.

Under the settlement, fenceline monitoring would detect fugitive emissions and implement repairs as needed. If the monitors detect emissions above certain levels, site workers would conduct a field investigation and develop a response if the facility is responsible. Shell would also monitor and maintain the heating value of flares to track their efficiency. The company would monitor the flares more frequently than its air permit requires.

Vice President of Appalachia Petrochemicals Ate Visser said that with the settlement behind it, Shell can now focus on delivering the facility with state-of-the-art technology to better protect the environment. The cracker is being built on a 400-acre site in Beaver County. It’s designed to consume more than 100,000 b/d of ethane to produce ethylene and polyethylene, which are key building blocks for plastics. Production is expected to begin sometime in the early 2020s.