Danger zone: Indiana produces 6th most toxic chemicals in U.S.

The United States of Toxins: This map shows the total pounds of toxic chemicals released into the environment by state. Indiana releases the sixth most chemicals of all states across the country, according to the U.S. Environmental Protection Agency's toxic release database.

Indiana released a chemical soup of toxins into the environment last year — 133 million pounds of them, to be exact. 

The amount is the equivalent weight of roughly 950,000 American adults, or the population of Marion County, and made Indiana sixth in the country in terms of toxic release. 

The U.S. Environmental Protection Agency requires large industrial facilities to report their toxic releases into the environment every year. Priceonomics, a group that analyzes and shares data, worked with one of their customers to examine the EPA's Toxic Releases Inventory and its recently added 2016 data. That customer, Ode, creates environmentally conscious cleaning products.

With a handful of the nation's most toxin-producing companies in Hoosiers' backyards, it may come as no surprise that Indiana and several of its cities and counties near the tops of lists for their chemical releases.

Here's what you need to know: 

Indiana released more toxic chemicals into the environment in 2016 than 44 other states. At 133 million pounds, that is more than any neighboring Midwest states. Alaska topped the list, emitting 834 million pounds, followed by Nevada, Utah, Texas and Louisiana. New Hampshire released the fewest toxins, only 290,000 pounds. 

Marion County is among the top 50 counties in the U.S. that produce the most toxins, releasing nearly 11 million pounds into the environment in 2016. Three other Indiana counties find themselves on the list, including Lake County — home of Gary —  in the top 10, as well as Spencer and Posey counties. 

Of the country's 50 most populous cities, Indianapolis leads the pack with 10.9 million pounds of toxic releases. Houston came in second with 6.6 million pounds. Indiana's capital also beat out Chicago, Detroit and Louisville, Ky., among others. With its history in manufacturing and known for its coal power plants, steel mills and auto factories, Indianapolis has long been cited for its poor air quality. 

Indianapolis also produced some of the most toxins per capita and per square mile last year, finding itself in the top 10 when measured against the 100 most populous U.S. cities. More specifically, nearly 13 pounds of chemicals were released per person — more than triple the average — and roughly 30,150 pounds per square mile. 

Four other Indiana cities are among the top 50 that produce the most toxins, when population is not considered. Gary — ranked 13th nationally — has the most releases in the state: 23.9 million pounds of chemicals. Also on the list are Rockport, East Chicago and Mount Vernon. 

Indiana has 916 toxin-releasing facilities, and those in the primary metals industry are some of the biggest culprits for the amount of toxins they release. This includes companies such as U.S. Steel Corp. in Gary, AK Steel Holding Corp., with a location in Rockport; and ArcelorMittal USA in East Chicago. These three companies are among the top 25 companies that produce the most pounds of toxic chemicals released into the environment nationally. 

The top five chemicals released in Indiana can damage the nervous system and cause other illnesses, as well as be toxic to wildlife. They include zinc compounds, manganese compounds, nitrate compounds, lead compounds and sulfuric acid. The zinc, manganese and lead compounds are often products of mining, while nitrate is a common byproduct from fertilizers and agriculture and sulfuric acid from manufacturing. 

This information was gathered from the EPA's Toxic Releases Inventory database as well as provided by the analysis of Priceonomics and Ode

Call IndyStar reporter Sarah Bowman at (317) 444-6129. Follow her on Twitter and Facebook: @IndyStarSarah. IndyStar's environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.