Thunder Over Louisville is not the harmless holiday the city treats it as. While Thunder and other pre-Derby celebrations bring tourism and boost local businesses and morale, they also boost levels of toxic chemical and metal pollutants in the surrounding air and water.

In 2011, Thunder resulted in 3 tons of perchlorate being released into the Ohio River. Perchlorate is a naturally occurring and manmade chemical used in rocket fuel and fireworks and can disrupt the function of the thyroid gland and impact fetal and infant brain development and growth. The Environmental Protection Agency (EPA) announced it would regulate perchlorate in drinking water in 2011.

It may feel almost blasphemous to talk about this source of local pride (and revenue) in a critical manner, but it is important that we continue to do so if we want to see progress with the environment.

Air pollution from fireworks festivals such as Thunder is so bad that last year the sale of fireworks was banned in Delhi by the Indian Supreme Court after the cloud of smoke and chemical smog from earlier Diwali celebrations caused a citywide air quality crisis.

In Britain, hospitals around the Thames see a spike in asthma-related admissions the night of and day after fireworks festivals, such as Guy Fawkes Day.

All over the world, there have been countless studies that all show that the effects of fireworks on the surrounding area linger up to days after the crowds leave, and can easily make their way into water supplies. Firework after-effects don’t only stay in the same place; they travel in plumes of toxic smog and chemical discharge, releasing into waterways. With Thunder being right on the Ohio River, many environmentalists are calling for research on and testing for contaminants and their effects in the Ohio. Since most research on firework pollutants in waterways has been done on smaller bodies of water, we don’t know how long the pollutants last, how quickly the water dilutes them or how bad the effects are. However, any contact with contaminants such as these has adverse effects on wildlife. The Ohio River is home to many endangered species of mussels.

This year, Thunder Over Louisville is taking place on Earth Day. Local environmental organizations are hosting an Earth Walk in Iroquois Park from 9 AM until noon. It will hopefully raise funds and awareness for these programs and the problems they face.