| Reading Room File Cabinet | Description |
| Office of the Administrator (AO) | The Office of the Administrator (AO) provides executive and logistical support for the EPA Administrator. AO supports the leadership of EPA's programs and activities to protect human health and the environment. |
| Office of Air and Radiation (OAR) | The Office of Air and Radiation (OAR) develops national programs, policies, and regulations for controlling air pollution and radiation exposure.
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| Office of Chemical Safety and Pollution Prevention (OCSPP) | Using sound science as a compass, OCSPP’s mission is to protect you, your family, and the environment from potential risks from pesticides and toxic chemicals. |
| Office of the Chief Financial Officer (OCFO) | OCFO formulates and manages EPA’s annual budget and performance plan, coordinates EPA’s strategic planning efforts, develops EPA’s annual Performance and Accountability Report, and implements the Government Performance and Results Act. |
| Office of Enforcement and Compliance Assurance (OECA) | The Office of Enforcement and Compliance Assurance (OECA) goes after pollution problems that impact American communities through vigorous civil and criminal enforcement. |
| Office of Environmental Justice and External Civil Rights (OEJECR) | The Office of Environmental Justice and External Civil Rights (OEJECR) supports the agency’s mission by providing leadership on EPA’s environmental justice and external civil rights priorities. |
| Office of General Counsel (OGC) | The Office of General Counsel (OGC) is the chief legal advisor to EPA, the federal agency with primary responsibility for implementing the nation’s environmental laws. |
| National FOIA Office | National Freedom of Information Act Office, an office within Office of General Counsel, administers the FOIA at EPA. |
| Office of Inspector General (OIG) | The Office of Inspector General is an independent office within EPA that helps the agency protect the environment in a more efficient and cost effective manner. |
| Office of International and Tribal Affairs (OITA) | EPA's Office of International and Tribal Affairs (OITA) leads EPA’s international and tribal engagements, working across EPA’s programs and regions to develop and implement policy and programs that protect U.S. public health and the environment. |
| Office of Land and Emergency Management (OLEM) | The Office of Land and Emergency Management provides policy, guidance and direction for the Agency's emergency response and waste programs. |
| Office of Mission Support (OMS) | The Office of Mission Support (OMS) leads the agency’s core mission support functions to improve efficiency, coordination, and customer experience for internal customers, stakeholders, and the public. |
| Office of Research and Development (ORD) | The Office of Research and Development (ORD) is the scientific research arm of EPA. Its leading-edge research informs Agency decisions and supports the emerging needs of EPA stakeholders, including the Agency’s state, tribal, and community partners. |
| Office of Water (OW) | The Office of Water ensures drinking water is safe, and restores and maintains oceans, watersheds, and their aquatic ecosystems. |
| Region 1 | Headquartered in Boston, serving CT, ME, MA, NH, RI, VT, and federally recognized Indian Nations. |
| Region 2 | Headquartered in New York City, serving NJ, NY, Puerto Rico, the U.S. Virgin Islands, and federally recognized Indian Nations. |
| Region 3 | Headquartered in Philadelphia, serving DE, DC, MD, PA, VA, WV, and federally recognized Indian Nations. |
| Region 4 | Headquartered in Atlanta, serving AL, FL, GA, KY, MS, NC, SC, TN, and federally recognized Indian Nations. |
| Region 5 | Headquartered in Chicago, serving IL, IN, MI, MN, OH, WI, and federally recognized Indian Nations. |
| Region 6 | Headquartered in Dallas, serving AR, LA, NM, OK, TX, and federally recognized Indian Nations. |
| Region 7 | Headquartered in Kansas City, serving IA, KS, MO, NE, and federally recognized Indian Nations. |
| Region 8 | Headquartered in Denver, serving CO, MT, ND, SD, UT, WY, and federally recognized Indian Nations. |
| Region 9 | Headquartered in San Francisco, serving AZ, CA, HI, NV, American Samoa, Commonwealth of the Northern Mariana Islands, Federated States of Micronesia, Guam, Marshall Islands, Republic of Palau, and federally recognized Indian Nations. |
| Region 10 | Headquartered in Seattle, serving AK, ID, OR, WA, and federally recognized Indian Nations. |