Pima County has filed a lawsuit against Rosemont Copper, a mining company in Tucson, after the county said the company violated the region's lighting restrictions.

Pima County Chief Building Official Yves Khawam said the restrictions are in place to protect the multiple observatories located on Mount Hopkins.

“The closer we get to the observatory, the more restrictive the lighting becomes. And so, Rosemont is actually located in the backyard of the Smithsonian Observatory,” Khawam said.

Khawam said Rosemont Copper has stated it should exempt from the lighting code because it’s regulated by the state mine inspector, not the county.

Khawam said his office wants state and county laws to help regulate the light-pollution problem.