Environmental protection advocates called for urgent action on Thursday after a report published in Science detailed a huge rise in low-oxygen “dead zones” within the planet’s oceans.

The increased use of chemical fertilizers by the industrial agriculture sector over the past several decades , the study  warns, has prompted large-scale run-off of sewage and other byproducts entering ocean waters, causing deoxygenated dead zones to quadruple in size since 1950—now covering an area roughly the size of the European Union.

“These findings are no surprise, and further confirm that the unchecked pollution from industrial agriculture has reached crisis levels and requires immediate action,” Lucia von Reusner, campaign director for Mighty Earth, said in a statement. “Companies like Tyson Foods are driving the demand for vast quantities of unsustainably-produced corn and soy that are leaking the bulk of the nutrient pollution into our waterways, in addition to the manure that is often dumped on fields where it then washes off into surrounding waterways.”

Low-oxygen dead zones make the ocean less inhabitable for marine life, suffocating creatures and reducing the area where they’re able to thrive.