ROCKFORD, Ill. (WTVO) — Rockford’s airport takes another step forward toward the completion of a $50 million cargo expansion project with a study aimed at assessing the controversial “Bell Bowl Prairie.”

Administrators for the Chicago Rockford International Airport (RFD) and the Federal Aviation Administration have filed a biological assessment with the Fish and Wildlife Service to look at the potential impact construction could have on the Rusty Patch Bumblebee that was found in the area.

Work on the area is on hold until the fall after RFD agreed not to disturb the area during the bumblebee’s mating or nesting season.

Environmental advocacy groups have been pushing to save the patch of land, owned by the airport, which they say is home to important prairie grasses and the bumblebee.

Airport administrators say their original expansion plans have changed little, with the exception of eliminating a detention pond.

“With the biological assessment, we did look at different roadway configurations, as part of it, but, honestly, the roadway as originally aligned, with the removal of the detention basin, is the safest option for us,” said RFD’s Zack Oakley. “So, that’s the option we’re still proposing, planning on doing, is constructing that road with the same configuration.”

RFD expects to have an opinion from Fish and Wildlife later this summer.