PlainEnviro

Top 10 EPA TRI Chemicals by Total Reported Release Mass

EPA Toxics Release Inventory reportable chemicals ranked by total pounds released across all reporting facilities. Updated with each EPA TRI data release.

Research period:

Compiled by PlainEnviro Editorial on 2026-07-13

Research question

Among 600+ TRI-reportable chemicals, which carry the largest total reported release mass, and how does carcinogen/PBT designation overlap with the top of the distribution?

Methodology

This ranking is built directly from the U.S. Environmental Protection Agency’s published environmental data, ranking EPA Toxics Release Inventory (TRI) chemicals by the total pounds released across all reporting facilities. Every figure shown is taken straight from the EPA’s release – nothing is hand-entered, estimated, or adjusted beyond display formatting – and each number is auditable back to its source record through the links in the table.

Chemicals with no reported release value are left out rather than shown as zero, so the list reflects only the chemicals the EPA actually reports releases for. The EPA occasionally suppresses individual values for confidentiality or data-quality reasons; those records are excluded here by design rather than displayed as zeros. Values appear exactly as the EPA publishes them, with thousands separators added only for readability.

The figures reflect the most recent EPA data release we have processed. When the EPA publishes a revision, the updated values flow through to this page automatically, so there are no hand-copied numbers to fall out of date. Alongside the top ten, we show whole-population context – the total number of chemicals reported and the average release mass – so you can see how concentrated the top of the distribution really is.

See the methodology page for the full source list, data vintages, and how each metric is defined.

Top 10 EPA TRI Chemicals by Total Reported Release Mass

Chemicals ranked by EPA-reported total release mass

million lbs

What this shows Reported release mass concentrates in a few heavy-metal and inorganic compounds; mass totals reflect reporting volume, not relative toxicity.

Source U.S. Environmental Protection Agency As of 2023

The ranked top 10

All 10 ranked chemicals, drawn directly from the EPA dataset.

# Chemical CAS# Facilities Total releases (lbs)
1 Zinc compounds N982 3,627 2,967,441,248.015
2 Lead And Lead Compounds N420 3,582 1,385,210,410.6
3 Nitrate compounds (water dissociable; reportable only when in aqueous solution) N511 2,961 1,368,600,125.911
4 Lead compounds N420 3,142 1,325,869,660.852
5 Arsenic compounds N020 230 1,167,194,619.448
6 Ammonia 7664-41-7 2,760 866,905,216.745
7 Methanol 67-56-1 2,732 645,019,675.662
8 Manganese And Manganese Compounds N450 1,072 632,404,357.833
9 Barium compounds (except for barium sulfate (CAS No. 7727-43-7)) N040 697 585,303,128.431
10 Manganese compounds N450 1,675 433,120,541.347

Source: U.S. Environmental Protection Agency, EPA TRI Chemicals consolidated rollup. Figures are drawn directly from the EPA release and refresh when the EPA publishes an update. U.S. Environmental Protection Agency, EPA TRI Chemicals consolidated rollup. Figures are drawn directly from the EPA release and refresh when the EPA publishes an update.

Findings

Top entity in the ranking

The top-ranked record in this dataset is Zinc compounds, with a value of 2,967,441,248.015 on the Total releases (lbs) column. The full top-10 set is rendered in the table above. Every value is drawn directly from the EPA data. When the source agency publishes a revision, the ranking and the text around it update automatically.

Distribution shape

The top-ranked chemical, Zinc compounds, accounts for 2,967,441,248.015 lbs of reported releases – about 6.9× the 10th-ranked chemical (433,120,541.347 lbs). Reported mass is highly concentrated: a few high-volume chemicals dominate the total. The full distribution beyond this top-10 cut is summarized in the aggregate context section below and explored in the linked entity profiles.

Aggregate context

Across all 559 reported chemicals with a nonzero release value, the combined release mass is 16,588,800,760.771 lbs, an average of 29,675,851 lbs per chemical. The top-10 chemicals shown above account for 68.6% of that combined total. Chemicals with no reported value are excluded from these totals, exactly as they are from the ranking. These totals are computed across the same EPA dataset shown in the ranking.

Source provenance

The records in this ranking originate from U.S. Environmental Protection Agency, specifically the EPA TRI Chemicals consolidated rollup. PlainEnviro presents the EPA’s published release here unchanged except for display formatting. Because the figures are drawn directly from that release, a revised EPA dataset propagates to this page automatically, with no stale hand-copied numbers. The methodology page documents the source URL, the vintage date, and how the data is prepared.

Why this ranking matters

Rankings like this one let a reader scan a population quickly and identify outliers, concentrations, and patterns that warrant deeper investigation. The detail pages linked from each entity in the table above give the full per-entity context: time-series history where available, related metrics from adjacent tables, and links onward to the underlying source records. The methodology page explains how an entity earns inclusion in the dataset and how the ranking column is computed at the source.

What this analysis cannot tell us

TRI reportable chemicals are a defined list maintained under EPCRA section 313 with periodic additions and removals, the list changed across reporting years and not all chemicals were tracked for the entire TRI history. Reported release mass aggregates on-site air, water, and land releases plus off-site transfers; the unit (pounds) is a mass total and does not weight by toxicity, persistence, or bioaccumulation potential. Carcinogen and PBT (persistent, bioaccumulative, toxic) flags reflect EPA designation status as of the most recent data release and may evolve as toxicology evidence accumulates. Facility-level reporting accuracy is constrained by the regulated party's measurement and estimation method; large variance exists in measurement quality across industrial sectors.

Secondary cut from the same source

Top 10 TRI chemicals by reporting facility count

facilities

What this shows Facility count is a different lens than total mass: a chemical used at many small sites can outrank a high-mass chemical concentrated at a few large operations.

Source U.S. Environmental Protection Agency As of 2023

Related data

Sources