A judge has ordered Exxon Mobil to pay a penalty of nearly $20 million for releasing 10 million pounds of pollutants into the air over the course of eight years from a refining and chemical complex east of Houston.

U.S. District Judge David Hittner in a ruling Wednesday determined that Texas-based Exxon on thousands of occasions from 2005 to 2013 violated federal clean-air standards.

The Houston Chronicle reports (http://bit.ly/2oMZ7Lr ) the finding is the result of a lawsuit filed in 2010 by two environmental groups.

The groups argued Exxon collected more than $14 million in economic benefits by delaying measures to curb the emissions from its plant in Baytown. They contend the pollution could have been detected earlier using improvements such as infrared imaging technology.

Exxon says it's considering an appeal.