Guam, GU

Moderate Risk (47/100)

Transparent derived index from EPA TRI / SDWIS / Superfund extracts: not an official EPA rating. Fixed caps: facilities ≤25 pts (50+ = max), log10 releases ≤25 pts, Superfund ≤25 pts (5/site), health-violation systems ≤15 pts (3/system), high-chemical facilities ≤10 pts. Bands: High ≥60, Moderate ≥30. See methodology.

Environmental data for Guam in Guam

TRI sites such as Naval Base Guam-Apra Harbor WWTP; Guam Power Authority; South Pacific Petroleum Corp; SDWIS systems such as GWA NORTHERN WATER SYSTEM; GWA CENTRAL WATER SYSTEM; GWA SOUTHERN WATER SYSTEM; NPL sites such as Andersen Air Force Base; Ordot Landfill anchor Guam, GU's EPA extract. Derived burden score 47/100 (Moderate Risk) uses fixed national caps on density, log release volume, Superfund count, and health-flagged systems - not an official EPA rating.

Health-flagged SDWIS rows in Guam include GWA CENTRAL WATER SYSTEM; GWA SOUTHERN WATER SYSTEM, while Naval Base Guam-Apra Harbor WWTP leads reported TRI pounds among local Form R filers. No AQS county monitors report here.

Burden score 47/100 (Moderate Risk) is the only weighted composite on this page. The tables below list every TRI facility, SDWIS system, and Superfund site EPA has on record for Guam -- not just the names called out above -- reproducing the disclosure history as filed, not a current-safety verdict. Extract current as of 2026-08-25.

Release-over-release change

What changed for Guam, GU: EPA TRI 2023 reporting year

2022 → 2023

Same facilities, both years

-31.7%

8 facilities that filed in 2022 and 2023

Whole inventory

-31.6%

341.4 thousand lb → 233.4 thousand lb, every facility that filed

Between the two reporting years, 1 facility filed for the first time and 1 stopped filing. Facilities entering or leaving the inventory are excluded from the same-facility comparison above.

  • Guam, GU's total reported releases fell from 341.1 thousand lb in 2022 to 232.9 thousand lb in 2023, based on EPA TRI filings.
  • Guam, GU's air releases fell from 129.0 thousand lb in 2022 to 32.4 thousand lb in 2023, based on EPA TRI filings.
  • Guam, GU's land releases rose from 1.5 thousand lb in 2022 to 1.8 thousand lb in 2023, based on EPA TRI filings.
  • Guam, GU's water releases fell from 210.5 thousand lb in 2022 to 198.7 thousand lb in 2023, based on EPA TRI filings.
TRI Facilities
10
Water Systems
3
Superfund Sites
2
Total Releases
2.0M lbs

Water Systems (3)

System System pop (SDWIS) Violations
GWA NORTHERN WATER SYSTEM 139,207 0
GWA CENTRAL WATER SYSTEM 21,398 4
GWA SOUTHERN WATER SYSTEM 5,801 2

TRI Facilities (10)

# Facility Total Releases
1 Naval Base Guam-Apra Harbor WWTP 1.1M lbs
2 Guam Power Authority 756.7K lbs
3 South Pacific Petroleum Corp 63.1K lbs
4 Andersen Air Force Base (us Air Force) 14.3K lbs
5 Mobil Oil Guam Inc (cabras Island Terminal) 13.6K lbs
6 Yigo Power Plant 3.7K lbs
7 Tenjo Vista Power Plant 1.4K lbs
8 Dededo Combustion Turbine Generating Facility 479 lbs
9 Tristar Terminals Guam Inc. 237 lbs
10 Hawaiian Rock Products-Guam 187 lbs

Superfund Sites (2)

Site Name Status HRS Score
Andersen Air Force Base NPL Site 50.00
Ordot Landfill NPL Site 0.00

Cities in Guam (7)

Piti
4 facilities · 0 water
Yigo
2 facilities · 0 water
Mangilao
1 facilities · 3 water
Agat
1 facilities · 0 water
Dededo
1 facilities · 0 water
Santa Rita
1 facilities · 0 water
Ordot
0 facilities · 0 water

Frequently Asked Questions

What is the environmental risk level in Guam, Guam?
Guam, GU has an environmental risk score of 47/100 (Moderate Risk), based on 10 TRI facilities, 2 Superfund sites, and 3 water systems on record. 2 water systems have health-based violations. Source: EPA TRI, SDWIS, and Superfund NPL.
Are there Superfund sites in Guam?
Yes, Guam, GU has 2 Superfund sites on the EPA National Priorities List (NPL). Superfund sites are contaminated locations that require long-term cleanup under the EPA Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).
How many toxic release facilities are in Guam?
Guam, GU has 10 TRI-reporting facilities on record with the EPA Toxic Release Inventory, with a combined total of 2.0M lbs in reported toxic releases. TRI facilities self-report annual chemical release data to the EPA.
What is the air quality in Guam?
Air quality monitoring data (EPA AQS) is not available for Guam, GU. This may indicate no EPA monitoring stations are located in the county. For regional air quality data, see the state environmental profile or visit EPA's AirNow.gov.
Is the drinking water safe in Guam?
Guam, GU has 3 EPA-regulated water systems. 2 systems have reported health-based violations (MCL exceedances). A past violation does not necessarily mean water is currently unsafe. For current water quality, contact your local water utility. Source: EPA SDWIS.
What environmental agencies cover Guam?
Environmental compliance in Guam, Guam is overseen by the U.S. Environmental Protection Agency (EPA) at the federal level and the Guam state environmental agency. Facilities report to the EPA Toxic Release Inventory, water systems are regulated under the Safe Drinking Water Act, and contaminated sites are managed under the Superfund program. Contact your state environmental agency for local concerns.

What does this county environmental profile show?

This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.

Related

Data sourced from U.S. EPA environmental datasets. See our methodology for details. Retrieved and formatted by PlainEnviro