The National Park Service is planning to conduct another fireworks show at Mount Rushmore National Memorial on July 3, 2020.
One of the reasons for prohibiting massive fireworks displays over the faces of the four presidents on Mount Rushmore National Memorial is that the previous 11 fireworks shows between 1998 and 2009 contaminated the water at the memorial. The fireworks explosions left perchlorate on the ground which has been linked to fetal and infant brain damage, and it worked its way into the water table. In 2016 a USGS report showed that a maximum perchlorate concentration of 54 micrograms per liter was measured in stream samples at Mount Rushmore between 2011 and 2015. That was about 270 times higher than in samples collected from sites outside the memorial, which were 0.2 micrograms per liter.
In recent months the Environmental Protection Agency was considering establishing a limit on perchlorate of 56 micrograms per liter, almost 4 times higher than the limit of 15 proposed by the administration in 2009, but it was never implemented. If adopted, the new limit would have been a policy statement by the administration that the extremely high perchlorate levels caused by the fireworks were acceptable, but just barely — by 2 micrograms per liter.
But the EPA announced June 18, 16 days before the scheduled July 3, 2020 fireworks show, that they will not regulate perchlorate, period. This makes it easier for the Governor of South Dakota and the President, who both pushed to resume the fireworks shows, to feel they have eliminated one of the barriers to continuing the explosions over the four faces.
The negative aspects of exploding fireworks over the sculpture, as learned from the 11 times it has been done in the past, include two other issues in addition to carcinogens in the water:
During those 11 events at least 20 documented wildfires were ignited by the fireworks in the middle of the wildfire season.
The trash dropped by the exploding shells onto the Monument and the forest can never be completely picked up. Left on the ground are unexploded shells, wadding, plastic, ash, pieces of the devices, and paper; stuff that can never be totally removed in the very steep, rocky, rugged terrain.