Charleston, SC

Charleston, SC

The City of Charleston is home to an estimated 134,875 residents, and it’s located in Charleston County, SC.

This report will help you become better acquainted with Charleston and the surrounding area by addressing the following questions:

  • Are there any hazardous sites in Charleston County, SC?
  • How clean is the air in Charleston County, SC?
  • What’s the average radon level for homes in Charleston County, SC?
  • Is the water in Charleston County, SC safe to drink?

Hazardous Sites near Charleston, SC

There are two Superfund sites in Charleston County, SC. Superfund sites, like Koppers Co., Inc. (Charleston Plant) in Charleston, SC, are areas that have been contaminated with hazardous substances. If not for the cleanup efforts orchestrated by the EPA, these sites could endanger people living in nearby communities.

The EPA uses the Hazardous Ranking System (HRS) to quantify the risk a contaminated site poses to human health and the environment. Sites assigned HRS scores of 28.5 or greater qualify for placement on the National Priorities List (NPL), and are eligible to receive federal funding for cleanup efforts.

Before the EPA deletes a site from the NPL, it conducts reviews to ensure the cleanup was sufficient. As a result, some sites remain on the active site list long after cleanup activities are complete.

For more information about the Superfund sites located in the Charleston, SC area, be sure to review the map and background information provided below:

Map Legend:


A. Koppers Co., Inc. (Charleston Plant) (HRS Score: 50)

The Koppers Co., Inc. (Charleston Plant) site, the location of a former wood treatment facility, is located in Charleston, SC.

Contaminants found at the Koppers Co., Inc. (Charleston Plant) site include:

  • Arsenic
  • Chromium
  • Lead
  • Polycyclic Aromatic Hydrocarbons (PAHs)
  • Dieldrin

B. Macalloy Corporation (HRS Score: 50)

The Macalloy Corporation site, where a ferrochromium alloy smelting plant operated from 1941 to 1998, is located in North Charleston, SC.

Contaminants found at the Macalloy Corporation site include:

  • Antimony
  • Arsenic
  • Chromium
  • Iron
  • Chromium(VI)

Air Quality in the Charleston, SC Area

The two most widespread forms of air pollution are ozone (smog) and particle pollution (soot). Exposure to these harmful pollutants, for even just a short period, can have adverse effects on your health.

Thanks to data collected by air monitoring equipment located across the country, the American Lung Association (ALA) is able to assess and track our air quality using three metrics:

  • Ozone
  • Short-term Particle Pollution
  • Year-round Particle Pollution

In their 2019 annual report, the ALA rated the air quality in Charleston County, SC as follows:

Ozone Pollution

Grading Scale: A-F

Particle Pollution

Grading Scale: A-F

Particle Pollution

Grading Scale: Pass/Fail

Radon Levels in Charleston, SC Area

Air quality inside your home can be impacted by a number of factors, including the presence of hazardous substances in building materials (asbestos, lead, formaldehyde, etc.) and local radon levels.

Radon is a naturally occurring gas you cannot see or smell. It can build up inside your home and negatively impact your indoor air quality as well as your health.

To provide a guideline, the EPA assigned one of three zones to each U.S. county and county equivalent:

  • Zone 1 (higher radon levels)
  • Zone 2 (moderate levels)
  • Zone 3 (lower levels)

The average indoor radon reading in Charleston County, SC is predicted to be less than 2 picocuries per liter (pCi/L), so the county has been assigned EPA Radon Zone 3.

EPA Radon Zone

But, it's worth mentioning homes with elevated levels of radon have been found in all three radon zones. So, despite the fact Charleston, SC is in EPA Radon Zone 3, you should have a radon test performed on any home you purchase in the area.

Water Quality in Charleston, SC Area

In accordance with the Safe Drinking Water Act (SDWA), the EPA sets regulatory limits for drinking water contaminants known to cause adverse health effects.

The following Charleston County, SC water provider(s) violated the maximum allowable level for one or more regulated contaminants:

Filter ValueWater SystemContaminantHealth Effects
45019Charleston Water System (Sc1010001)TTHMLiver, kidney, or central nervous system problems; increased risk of cancer 
45019Dewees Utilities (1050011)TTHMLiver, kidney, or central nervous system problems; increased risk of cancer 
45019Isle of Palms W/S Comm (1010004)FluorideBone disease (pain and tenderness of the bones); children may get mottled teeth 
45019Mt Pleasant Water Works (1010002)TTHMLiver, kidney, or central nervous system problems; increased risk of cancer 
45019Sullivans Island Town of (1010003)FluorideBone disease (pain and tenderness of the bones); children may get mottled teeth 

In addition to setting enforceable standards for harmful contaminants, the EPA also established guidelines to assist public water providers in managing the taste, odor and color of their drinking water.

To find out more about what’s in your drinking water, contact your utility company and request a copy of the latest Consumer Confidence Report.

Sources and Methods

Hazardous Sites: Identified using a report from the Environmental Protection Agency (EPA), hazardous sites detailed on represent sites contained on the National Priorities List (NPL) as of November 25, 2019.  The NPL is the list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States and its territories.  All site-related data was sourced from the EPA.

Air Quality: Grades for ozone, short-term particle pollution, and year-round particle pollution were obtained from State of the Air 2019, a report compiled by the American Lung Association.

Radon Zones: Radon zone designations were obtained using a public use dataset provided by the EPA (September 11, 2019).

Water Quality: Drinking water violation data was sourced from the Safe Drinking Water Information System (SDWIS), a public use database provided by the EPA.  The dataset included violations submitted to the database as of the third quarter of 2019.


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