The state's biggest polluter is ExxonMobil. Its Baton Rouge refinery had more than 500 accidents, accounting for more than 4 million pounds of pollution released in the air.

  Chalmette Refining had more than 400 accidents, sending 6 million pounds of pollution into the air and nearly 12 million gallons to the ground and in water. Chalmette Refining's 11.6 million gallon spill in 2008 dumped wastewater into canals leading to Lake Borgne.

  Accident reports show that the most common causes of refinery accidents include equipment failure (16 percent), faulty pipes or tubing (12 percent), or "no information given" (20 percent). ExxonMobil Baton Rouge reported more than 250 accidents and Chalmette Refining reported more than 100 with no information given as to cause.

  Weather — including hurricanes — accounted for 64 percent of accidents with ground and water pollution, and 27 percent of accidents with air emissions. — Woodward