Close Close Comment Creative Commons Donate Email Add Email Facebook Instagram Facebook Messenger Mobile Nav Menu Podcast Print RSS Search Secure Twitter WhatsApp YouTube

Why Louisiana’s Air Quality Is Going From Bad to Worse, in 3 Charts

Welcome to “Cancer Alley.”

Total Petrochemicals USA in St. Gabriel. (David Grunfeld/The Times-Picayune and The Advocate)

This article was produced in partnership with The Times-Picayune and The Advocate, which is a member of the ProPublica Local Reporting Network.

ProPublica is a nonprofit newsroom that investigates abuses of power. Sign up to receive our biggest stories as soon as they’re published.

The chemical industry is growing rapidly in Louisiana at the same time that the state is backsliding when it comes to toxic levels of cancer-causing chemicals in the air. We investigated. Here’s what we found.

1. Louisiana is approving new chemical plants in areas that already have the state's worst air quality — a region known as “Cancer Alley.”

We mapped estimated air toxicity levels along the lower Mississippi River using EPA data, then overlaid the locations of chemical projects that have been approved or are pending approval by the Louisiana Department of Environmental Quality.

2. Nationally, fewer plants with high emissions are operating. Not in Louisiana.

The number of facilities in Louisiana that are required to report their toxic releases to the government has increased since the 1980s. Nationally, that number has decreased. Plants with 10 or more employees in particular industries, in possession of chemical quantities above specific thresholds, are required to disclose information on their toxic emissions to the Toxics Release Inventory, a program administered by the EPA.

Facilities That Need to Report Their Toxic Releases Grew in Louisiana, but Fell Nationally


Note: Data does not include facilities that are required to report, but that reported releasing no toxics. (Environmental Protection Agency)

3. Air quality is improving overall in the United States, but in Louisiana, progress has been slower.

Nationally, the estimated spread of toxic chemicals in the air has been going down since the ‘80s, but the reductions in Louisiana are not as large as in other high-polluting states.

We found the 10 states with the most high-polluting areas, as estimated by an EPA model. We then compared the average toxic air levels of the 50 most polluted areas in these states at two points in time — 1988 and 2017. Louisiana is among the least improved.

Each high-polluting area is a census block group, an area of varying size that typically has fewer than 3,000 people.

How Much States Decreased Toxic Air Levels in Their Most Polluted Areas

We compared the average toxic air levels of the 50 most polluted areas in these states at two points in time — 1988 and 2017.

State Change in Estimated Toxic Air Levels
Oregon ↑ 11.6%
Virginia ↓ 56.1%
Indiana ↓ 73.0%
Louisiana ↓ 75.2%
Texas ↓ 76.9%
Ohio ↓ 91.2%
Pennsylvania ↓ 93.1%
Illinois ↓ 97.0%
Tennessee ↓ 97.0%
California ↓ 99.5%

ProPublica and The Times-Picayune and The Advocate looked at the states with the highest share of the most-toxic census block groups in 2017 and then examined how much improvement those states posted since 1988, when major sources of toxic air pollution began reporting their chemical releases to a national database called the Toxic Releases Inventory. A subsequent amendment to the Clean Air Act required those facilities to reduce their emissions with control technologies.


Our analysis found that a crush of new industrial plants will increase the air toxicity levels from cancer-causing chemicals in predominantly black and poor communities.

Our interactive map explores estimated air toxicity levels and the state’s system of dealing with toxic emissions in seven parishes along the lower Mississippi River. Read our full investigation here.

Filed under:

Protect Independent Journalism

ProPublica is a nonprofit newsroom that produces nonpartisan, evidence-based journalism to expose injustice, corruption and wrongdoing. We were founded ten years ago to fill a growing hole in journalism: newsrooms were (and still are) shrinking, and legacy funding models failing. Deep-dive reporting like ours is slow and expensive, and investigative journalism is a luxury in many newsrooms today — but it remains as critical as ever to democracy and our civic life. A decade (and five Pulitzer Prizes) later, ProPublica has built the largest investigative newsroom in the country. Our work has spurred reform through legislation, at the voting booth, and inside our nation’s most important institutions.

This story you’ve just finished was funded by our readers and we hope it inspires you to make a gift to ProPublica so that we can publish more investigations like this one that holds people in power to account and produces real change.

Your donation will help us ensure that we can continue this critical work. From the Trump Administration, criminal justice, health care, immigration and so much more, we are busier than ever covering stories you won’t see anywhere else. Make your gift of any amount today and join the tens of thousands of ProPublicans across the country, standing up for the power of independent journalism to produce real, lasting change. Thank you.

Donate Now

Lylla Younes

Lylla Younes is a news apps developer for ProPublica’s Local Reporting Network. She was previously a data reporter with New York Public Radio (WNYC) and Gothamist.

Latest Stories from ProPublica

Current site Current page