Electric Arc Furnace (EAF) Slag
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EAF slag is a rock-like material generated during the steel-making process. Approximately 130 facilities across the United States generate EAF slag. EAF slag is used as an alternative to rock fragments, both in encapsulated uses (e.g., contained in concrete) and unencapsulated uses (e.g., loose ground cover material). It is commonly used as road base material. In some states, EAF slag is also marketed for use in landscaping.
EPA’s preliminary research on EAF slag has shown that it is marketed as a gravel alternative for residential unencapsulated use in numerous states across the nation. “Unencapsulated use” means that it is used as loose ground cover and is not encapsulated with asphalt, concrete or with a similar cover that prevents access to it. In addition, the Agency determined that EAF slag contains elevated levels of manganese, hexavalent chromium, and other metals during a routine assessment of landscaping materials at a residential Superfund site cleanup.
It is currently unclear whether the unencapsulated EAF slag used near residences and schools in the United States causes risks to human health. Both manganese and hexavalent chromium can cause negative health outcomes in certain situations when these chemicals are ingested or inhaled and they are absorbed into the body. Too much manganese in the body can affect the nervous system especially in children, and hexavalent chromium can cause cancer. EPA also determined that some EAF slag dust samples were highly alkaline. Prolonged contact and inhalation of highly alkaline dust is associated with irritation of the skin and respiratory system.
This information combined with the Occupational Safety and Health Administration (OSHA)-required safety data sheets for EAF slag have raised questions about the material’s chemical and physical characteristics, how it is being used, and potential health concerns. EPA believes these questions will best be answered with independent research. As a result, EPA is continuing to gather information and evaluate this material.
To answer important questions about EAF slag, its uses, and potential for it to cause human health or environmental impacts, EPA is undertaking research targeted to key questions. This research will help inform future possible actions on this issue.
Potential Human Health Risks (National Academies)
EPA requested that the National Academies of Sciences, Engineering, and Medicine (National Academies or NASEM) produce an independent report by a panel of experts that evaluates potential human health risks from unencapsulated uses of EAF slag in residential areas. The study will include a focus on communities disproportionately impacted by pollution. The National Academies will review existing information on EAF slag to better determine what, if any, human health risks are associated with the residential use of unencapsulated EAF slag. If potentially serious risks are identified by the National Academies, EPA will use the evaluation along with other available information to develop risk management options to protect affected communities.
Public participation is built into the National Academies study process. Information about these meetings and public input along with details about the study will be posted on the NASEM website.
The Committee held an information-gathering session on September 12, 2022, which included a presentation on toxicokinetic modeling of manganese exposures. There was also an opportunity for members of the public to comment on the committee’s task. Check out the recording of the meeting on the National Academies website.
The Committee held a public information-gathering session on June 29, 2022 with presentations from industry representatives. The session also included a presentation on the Leaching Environmental Assessment Framework and how it is being used to evaluate EAF slag. Check out a recording of the meeting on the National Academies website.
The National Academies posted the committee appointments for this study and a link to their biographies on their website.
The NASEM Committee held an information-gathering session on February 7, 2022 with presentations from EPA representatives about the committee's task. Check out a recording of the meeting on their website.
Leaching Environmental Assessment Framework
EPA’s Office of Research and Development, in collaboration with Vanderbilt University, is conducting Leaching Environmental Assessment Framework (LEAF) testing on EAF slag. LEAF testing evaluates the release of chemicals from materials under different environmental conditions and will help determine if metals might be leaching from EAF slag into nearby soil or water. In addition, weathering and durability tests are being conducted on the slag.
EPA is currently conducting research to get more information on EAF slag, its uses, and potential for it to cause human health or environmental impacts. If you have concerns about EAF slag in your community as we move forward with this work, the Agency recommends contacting your EPA Regional Office. Information on EPA’s Regional Offices is available here.
Below is additional information that you may find helpful.
What is EPA doing to protect my health?
As part of EPA’s mission to protect human health and the environment, we are continuing to evaluate EAF slag in the following ways:
- EPA requested that the National Academies of Sciences, Engineering, and Medicine independently evaluate potential human health risks from the unencapsulated use of EAF slag in residential areas.
- In collaboration with Vanderbilt University, EPA is conducting leaching, weathering, and durability tests on EAF slag to help determine if metals might be released from the material under certain environmental conditions.
- EPA is coordinating with state agencies to compile information on the national extent of the use of this material in residential areas.
EPA is sharing what information we have on EAF slag at this time with the public. As more data and information is available, we will share it on this web page.
What are the possible health effects associated with EAF slag?
EAF slag dust may have a high pH level, which under prolonged contact and inhalation, has been associated with irritation of the skin and respiratory system. Additionally, EAF slag may contain manganese and hexavalent chromium. Too much manganese in the body can affect the nervous system, and hexavalent chromium can cause cancer. Children are often more vulnerable to chemicals than adults, due to differences in behavior and biology.
How can I detect if I have been exposed to manganese or hexavalent chromium?
Manganese and chromium are essential elements. Manganese and chromium are normally present in blood. If you are concerned, EPA recommends that you talk to your health care provider.
What can I do to minimize contact with EAF slag?
Currently, EPA recommends that residents take the steps below to minimize contact with EAF slag dust and small particles of the slag:
How do I know if I have EAF slag on my property?
EAF slag is a rock-like material generated during the steel-making process. Individuals who would like to know if material in their yards or driveways is EAF slag may look at the photos on the photos below and ask the source that supplied their driveway or landscaping materials.
Can my kids play on it?
As a precaution, children should limit contact with EAF slag, particularly if the material is fine and dusty. Prevent children from putting the material in their mouths, and minimize inhalation of dust. Wash children’s hands after contact with the material.
Can my pet play on it?
Yes. Concerns related to EAF slag used for landscaping material are primarily associated with childhood exposure. However, EPA recommends cleaning or brushing pets to avoid tracking EAF slag into homes.
Is it safe to eat vegetables grown in a garden near EAF slag in my yard?
At this time, EPA does not believe there are health risks from eating vegetables grown in gardens located close to EAF slag. EPA recommends that you minimize contact with EAF slag when gardening and that you wash your hands and produce before consuming it. Residents should also follow the best management practices above after gardening to avoid tracking EAF slag into the home. Examples include keeping dust mats next to exterior doors and leaving shoes and garden tools outside the home.
I don’t want this material in my yard or driveway. Is it ok if I remove the material myself?
EPA does not recommend that you remove EAF slag on your own. We recommend leaving EAF slag where it is and following our above practices to minimize contact with the material.
As a landscaper, how do I handle this material?
As a precaution, EPA recommends that workers handling EAF slag take protective measures to minimize inhalation and ingestion of EAF slag dust. These protective steps can be found in a document known as a Safety Data Sheet. Safety Data Sheets are documents identifying the properties of materials containing hazardous chemicals that vendors are required to provide upon request.
How is EAF slag regulated?
EAF slag is used across the nation. The management of the use and disposal of the material varies widely from state to state. Some states allow residential use; other states do not. For more information about how EAF slag is regulated in your state, contact your state environmental or public health agency.