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Cases / Chemical pollution · United States · 2018–2026

Dust and arsenic from the exposed Great Salt Lake lakebed: studies by USGS, the University of Utah and Utah State University

Nature's voice · report
No measurement of the harm done to me here is on record.
Did nature suffer? Not measured. Accounts differ ↓
Details not on record: 4 none on record · 1 insufficient · 1 not measured · 3 disputed · 1 unclear See the gaps
Accounts of the harm differ
Source of arsenic and other metals in dust along the Wasatch Front
  • Researchers Putman et al., USGS (2022): Wasatch Front dust was more enriched in trace metals than dust collected next to the lake, pointing to urban and industrial sources beyond the playa; highest dust fluxes were near the playa. US Geological Survey publication record
  • Researchers Putman et al., USGS (2025): Arsenic and sometimes lead are likely derived from the lake's playa emissions. US Geological Survey publication record
  • Researchers Molly Blakowski, Utah State University: The sediments reflect natural processes and more than a century of mining, waste disposal, oil refining and other industry; the dropping lake level has exacerbated the problem. TownLift

About 800 square miles of lakebed were exposed in January 2026. USGS, University of Utah and Utah State University studies report arsenic in dust above EPA residential soil screening levels, and a 2025 USGS-led paper concludes that suppressing dust from the lake's playa may decrease possible health risks for children in northern Utah; the sources attribute the metals to the playa and to industrial and historical land uses in differing proportions.

9% (175 square kilometres)Share of the exposed lakebed emitting dust (Kevin Perry, University of Utah)
University of Utah article of 5 September 2024; an earlier article (8 December 2022) said the share was about 9% in 2018 and could rise to 24% to 25%.

Status As of July 2026: peer-reviewed and agency studies report arsenic in lakebed-area dust above EPA residential soil screening levels; the exposure risk to people is not quantified in the sources reviewed and new monitors were being installed.

What?
As the lake receded, exposed lakebed became a source of dust containing arsenic and other metals; studies report arsenic above EPA residential soil screening levels in dust around the lake and in Salt Lake Valley. US Geological Survey publication record
Where?
Exposed lakebed of Great Salt Lake and the Wasatch Front, Utah. Utah Public Radio (Salt Lake Tribune)
When?
Studies 2022 to 2026; dust event 8 July 2026. KSL.com
Who?
Gained
None on record
Lost
  • Utah agencies and the public — The Commissioner's Office is helping finance dust monitoring; the plaintiffs allege the state will bear health-care and mitigation costs PBS Utah
Harmed
  • People in northern Utah, particularly young children — Putman et al. (2025) find children from birth to six years vulnerable at higher ingestion rates; a USU study found more than one-third of modelled child exposure scenarios exceeded levels of concern US Geological Survey publication record
Why?
The lakebed was exposed as the lake receded; sources attribute the metals to the playa and to industrial and historical land uses in differing proportions. US Geological Survey publication record
How?
Wind erodes dry playa crust into PM10 dust that carries metals; inhalation and ingestion are the pathways studied. KSL.com
6 of 6 questions (what, who, where, when, why, how) have an answer on record

What happened

The record, in order.

The Salt Lake Tribune reported in January 2026 that about 800 square miles of Great Salt Lake lakebed were exposed and that it dries out and erodes into dust storms along the Wasatch Front. PBS Utah reported in September 2025 that Kevin Perry of the University of Utah had mapped nearly 700 dust hot spots. A University of Utah article of 5 September 2024 reports, according to Perry, that only 9% of the exposed lakebed, or 175 square kilometers (about 43,000 acres), is emitting dust. KSL reported that during a dust event on 8 July 2026 PM10 concentrations reached about four times the healthy level and that arsenic is one of 13 substances identified as potential concerns in sediment around the lake.

Putman and six co-authors (GeoHealth, 26 October 2022; USGS publication record) analysed dust from 18 passive samplers near the lake and in Salt Lake Valley cities. They found trace metals in Wasatch Front dust "exceeded Environmental Protection Agency screening levels", the highest dust fluxes at sites near the playa, and Wasatch Front dust more enriched in trace metals than dust beside the lake, pointing to urban and industrial sources including mining, oil refining and past pesticide use; arsenic correlated positively with neighbourhood income. University of Utah science news reported that arsenic exceeded an EPA marker for residential soil at every site and was 35 times higher at one, and quoted Putman: "How much arsenic does there have to be over a 24-hour-period for dust to cause problems — we don't know." A 2025 GeoHealth paper by Putman and colleagues (5 August 2025) estimated non-cancer hazards for six age groups, found that thallium, arsenic, lead, cobalt and chromium contributed most to the estimated hazard and that arsenic and sometimes lead are "likely derived from the Lake's playa emissions", and concluded that "suppression of dust emissions from the Lake's playa may decrease possible health risks for children in northern Utah".

Attah, Kaur, Kelly, Fernandez and Perry (Atmospheric Environment, November 2024) reported that arsenic and lithium exceed EPA soil residential regional screening levels in the lake's dust and that the dust has higher oxidative potential than dust from other regional sources; the University of Utah article gives no concentrations. Perry told PBS Utah that "Every single measurement that I took over the 800 square miles of lakebed had higher arsenic concentrations" and that the levels were "More than a factor of ten" above what the EPA considers healthy. A Utah State University study published in spring 2026 (Blakowski and Brahney) found that leafy vegetables exposed to lake dust held elevated arsenic and uranium "even after thorough washing" and that more than one-third of modelled exposure scenarios exceeded levels of concern for children; Blakowski said, according to the USU release, that the playa sediments have been contaminated by a century of mining, waste disposal, oil refining and other human activities, and that the dropping level of the lake has exacerbated the problem; TownLift's account of the same release adds natural processes among the factors that shaped the sediments.

The complaint in the 2023 public-trust lawsuit alleges that exposed sediments consist of fine dust containing arsenic, mercury, nickel, lead and other pollutants. PBS Utah reported that the Great Salt Lake Commissioner's Office is helping finance an expansion of dust monitoring by the Utah Division of Air Quality and that California spent more than $2.5 billion mitigating dust at Owens Lake. KSL reported in July 2026 that the Division of Air Quality was installing new monitoring equipment and that Perry considered raising the lake's water level the most effective long-term solution.

  1. 2018About 9% of the lakebed a dust source (University of Utah, as reported in 2022)
  2. 2022Putman et al. publish dust study in GeoHealth (26 October)
  3. 2024Attah et al. publish oxidative potential study in Atmospheric Environment (online by 5 September)
  4. 2025Putman et al. GeoHealth paper on health hazards (5 August); PBS Utah reports Perry's arsenic measurements (10 September)
  5. 2026USU study published (reported 9 April); dust event on 8 July with PM10 about four times the healthy level

What was said

Claims, in the words of those who made them.

“How much arsenic does there have to be over a 24-hour-period for dust to cause problems — we don't know.”

“suppression of dust emissions from the Lake's playa may decrease possible health risks for children in northern Utah”

“Every single measurement that I took over the 800 square miles of lakebed had higher arsenic concentrations”

Kevin Perry, University of Utah · 10 September 2025 · PBS Utah

“It turns out that the dust from Great Salt Lake has more leachable metals that are bioavailable than we would wish.”

“Dust is an acute health hazard, but rarely measured for composition or bioavailability of potentially toxic components”

“It doesn't matter what the dust is made out of”

Kevin Perry, University of Utah, on acute effects of high PM10 · 9 July 2026 · KSL.com

Where accounts differ

Each party's account, side by side, with its source. The record does not settle these points; it shows them.

Source of arsenic and other metals in dust along the Wasatch Front
Researchers
Putman et al., USGS (2022)

Wasatch Front dust was more enriched in trace metals than dust collected next to the lake, pointing to urban and industrial sources beyond the playa; highest dust fluxes were near the playa.

US Geological Survey publication record
Researchers
Putman et al., USGS (2025)

Arsenic and sometimes lead are likely derived from the lake's playa emissions.

US Geological Survey publication record
Researchers
Molly Blakowski, Utah State University

The sediments reflect natural processes and more than a century of mining, waste disposal, oil refining and other industry; the dropping lake level has exacerbated the problem.

TownLift
Which health effect of the dust is the main concern
Researchers
Kevin Perry, University of Utah (July 2026)

He is more concerned about acute effects of high PM10, whatever the dust is made of.

KSL.com
Researchers
Putman et al. (2025)

Arsenic is a main contributor to the estimated non-cancer hazard for children.

US Geological Survey publication record

How it looked

What was shown, beside what was recorded.

Shown

    Recorded

    Who gained

    Money that reached nature, beside money that stayed elsewhere.

    Reached nature or the ground

    Not published
    No figure published.

    Gained elsewhere

    Not totalled
    Currency: USD · Window: n/a. All figures cover the same period. * Estimate built from cited figures.

    Responses on record

    • utah-division-of-air-quality (July 2026): Is installing new monitoring equipment to track dust emissions and their potential impacts (KSL, July 2026); its own statements on arsenic were not read. · KSL.com

    In court and with insurers

    Every proceeding and every insurer decision on record.

    Lawsuits and rulings

    No court case on record. No court has ruled on this case.

    Insurers

    No insurer decision on record.

    What nature saw

    Outcomes measured on the ground, and nature's note.

    Nature's report opens this page. Below: further outcomes measured on the ground.

    Lakebed exposed, January 2026
    about 800 square miles
    Salt Lake Tribune via Utah Public Radio
    Exposed lakebed emitting dust
    9% (175 square kilometres)
    Kevin Perry, 2024
    Arsenic in dust against EPA residential soil screening levels
    exceeded at every USGS site; one site 35 times higher
    Putman et al. 2022 as reported by the University of Utah; Perry: more than a factor of ten across the lakebed
    PM10 during the 8 July 2026 dust event
    about four times the healthy level
    KSL and the Salt Lake Tribune

    What we don't know

    Undisclosed, unproven, untried: recorded as data.

    Nature

    • Not measured Harm to nature: The record holds no measurement of harm to nature.
    • Disputed Source of arsenic and other metals in dust along the Wasatch Front

    Accounts

    • Disputed Which health effect of the dust is the main concern

    Record

    • None on record None on record in the sources reviewed: how much arsenic exposure over a given period causes harm; Putman stated 'we don't know'.
    • None on record None on record in the sources reviewed: arsenic concentrations in micrograms; the pages read give exceedances and ratios only.
    • None on record None on record in the sources reviewed: the Utah Department of Environmental Quality's own statements on dust and arsenic.
    • Disputed Disputed: the source of metals in Wasatch Front dust. Putman et al. (2022) found Wasatch Front dust more enriched than dust beside the lake and pointed to urban and industrial sources; Putman et al. (2025) wrote that arsenic is likely derived from the playa; Blakowski said the sediments reflect natural processes and more than a century of industry.
    • Unclear Unclear: the share of lakebed that is a dust source: 9% of the exposed lakebed in 2018 and 2024 per Perry; the University of Utah article of 2022 said it could rise to 24% to 25%.
    • Insufficient Unconfirmed: Perry's statement that arsenic across the lakebed is 'more than a factor of ten' above what the EPA considers healthy (PBS Utah); no measurement table was read.
    • None on record None on record in the sources reviewed: a finding on who is responsible for the dust or its costs.

    Did the harm stop?

    Not stopped on the sources reviewed: KSL reported a dust event with PM10 about four times the healthy level on 8 July 2026.

    Who paid?

    Not stated in the sources reviewed. PBS Utah reported that California spent more than $2.5 billion mitigating dust at Owens Lake; the Commissioner's Office is helping finance dust monitoring in Utah.

    Sources

    Voices on record: — Company or project— Government and regulators✓ Courts✓ Press and investigations— Communities and civil society✓ Researchers

    Connected cases

    Related matters, and cases linked to this one through the same organisations, with the role each played in both.

    Institutions

    EPA
    The US Environmental Protection Agency.