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Cases / Pesticides and agrochemicals · United States · 1967–2026

Monsanto/Bayer PCB and Roundup insurance suit v AIG

Nature's voice · report
No measurement of the harm done to me here is on record.
Did nature suffer? Not measured.
What the record lacks: 2 none on record · 3 insufficient · 1 not measured · 2 disputed See the gaps

In December 2025 Bayer sued the insurer AIG in St. Louis County, Missouri, over cover for more than $1.9 billion of PCB settlements and more than $10 billion of Roundup settlements. AIG's grounds for refusing are not public and the case was pending.

>$1.9bn PCB + >$10bn RoundupSettlements for which Bayer/Monsanto sought cover from AIG
Settlement totals to end-2024 as reported by the News Tribune from the filing. AIG's grounds for refusing cover are not public.

Status As of October 2026: Bayer's December 2025 suit against AIG in St. Louis County was pending; AIG's grounds were not public and no ruling was found.

What?
Bayer, which merged with Monsanto, sued the insurer AIG in December 2025 for cover of PCB and Roundup settlements that AIG had declined to pay. News Tribune
Where?
St. Louis County, Missouri (the insurance suit); the underlying PCB and Roundup litigation is in the United States. News Tribune
When?
Policies June 1967 to April 1986; settlements to end-2024; payment demands July and October 2024; suit early December 2025. News Tribune
Who?
Gained
  • Bayer / Monsanto — The Roundup herbicide segment sold €1.155bn in the third quarter of 2025 alone; the product has been on sale since 1974.
  • Bayer / Monsanto — The US Supreme Court ruled 7–2 for Monsanto in Monsanto v. Durnell on 25 June 2026. Faegre Drinker (law firm)
Lost
  • Bayer shareholders — Dividend at the legal minimum of €0.11 since 2024; €3.62bn net loss in 2025.
Harmed
  • Roundup claimants — About 65,000 claimants in Roundup cases were cited with the proposed 2026 class settlement. Bayer
  • Cities with PCB claims — Settled PCB claims against Monsanto for $550–650m through 2020, per EcoWatch. EcoWatch
Why?
Bayer sought insurance help with legal bills; AIG's reasons for refusing are not public. News Tribune
How?
Excess policies from 1967–1986 are being invoked in a civil suit after payment demands in 2024. News Tribune
6 of 6 questions answered from the record

What happened

The record, in order.

In early December 2025 Bayer, which merged with Monsanto, filed suit against the insurer AIG in St. Louis County, Missouri. The News Tribune reported the suit under the headline that Bayer sues AIG insurance to help with legal bills. The policies at issue are excess policies that ran from June 1967 to April 1986.

As reported, Bayer's exposure was more than $1.9 billion in PCB settlements by the end of 2024 and more than $10 billion in Roundup settlements. Payment demands were sent to the insurers in July 2024 (Roundup) and October 2024 (PCBs). AIG declined to cover the settlements. The insurer's grounds are not public, and the research found no insurer defence on file.

Bayer's own announcements frame the settlements. On 24 June 2020 it announced agreements to resolve major legacy Monsanto litigation: up to $10.9 billion for Roundup cancer claims, about $820 million for PCB water claims and up to $400 million for dicamba drift claims, with no admission of liability. On 17 February 2026 it announced a proposed Roundup class settlement of up to $7.25 billion, paid over up to 21 years.

On 25 June 2026 the US Supreme Court ruled 7–2 for Monsanto in Monsanto v. Durnell. A law-firm summary describes the ruling as preventing state-court failure-to-warn suits under the federal pesticide law; Bayer's press release was headed 'Monsanto wins landmark Roundup case at US Supreme Court'.

  1. 1967Start of the excess policies at issue (June 1967); they ran to April 1986
  2. 1969According to EcoWatch, Monsanto's PCB committee writes that there are too many customers and too much Monsanto profit to withdraw
  3. 2003Anniston PCB settlement: $550 million cash payment, to which Monsanto's insurers contributed
  4. 202024 June: Bayer announces up to $10.9bn for Roundup claims, about $820m for PCB water claims and up to $400m for dicamba drift; no admission of liability
  5. 2024Payment demands to insurers: July (Roundup) and October (PCBs)
  6. 2025Early December: Bayer sues AIG in St. Louis County, Missouri
  7. 202617 Feb: Bayer announces proposed Roundup class settlement of up to $7.25bn over up to 21 years; 25 June: US Supreme Court rules 7–2 for Monsanto in Monsanto v. Durnell

What was said

Claims, in the words of those who made them.

Where accounts differ

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

Is AIG obliged to cover the PCB and Roundup settlements?
Company or project
Bayer / Monsanto

Sent payment demands in July 2024 (Roundup) and October 2024 (PCBs) and sued in December 2025 under excess policies running from 1967 to 1986.

News Tribune
Company or project
AIG

Declined to cover the settlements; its grounds are not public.

News Tribune
Can Roundup users bring state-law failure-to-warn claims?
Courts
US Supreme Court

Ruled 7–2 on 25 June 2026 for Monsanto in Monsanto v. Durnell; a law-firm summary says the ruling prevents failure-to-warn suits.

Faegre Drinker (law firm)
Company or project
Bayer / Monsanto

Called the outcome a landmark win in its press release headline.

Bayer
Government and regulators
US EPA

the sources reviewed say EPA told Bayer it would not accept a cancer warning, and that Bayer used the letter before the Supreme Court.

International bodies
International Agency for Research on Cancer

Classified glyphosate as 'probably carcinogenic' in 2015; the classification stands.

How it looked

What was shown, beside what was recorded.

Shown

  • Agreements to resolve major legacy Monsanto litigation, with no admission of liability
    Bayer, announcement of 24 June 2020 · Bayer
  • 'Monsanto wins landmark Roundup case at US Supreme Court'
    Bayer, press release headline · Bayer
  • Mission 'Health for all, Hunger for none' and a goal of reaching 100 million smallholder farmers by 2030
    Bayer, sustainability commitments page · Bayer

Recorded

  • The suit covers excess policies running from June 1967 to April 1986. Exposure: more than $1.9bn in PCB settlements by end-2024 and more than $10bn in Roundup settlements. Payment demands went out in July 2024 (Roundup) and October 2024 (PCBs); AIG declined; the grounds are not public.
  • Bayer's 24 June 2020 announcement: up to $10.9bn for Roundup cancer claims, about $820m for PCB water claims and up to $400m for dicamba drift, with no admission of liability.
  • Proposed 2026 Roundup class settlement: up to $7.25bn over 21 years; about 65,000 claimants in Roundup cases; litigation provisions rose to €11.8bn (the sources reviewed citing Bayer's 2026 release).
  • US Supreme Court, 25 June 2026, Monsanto v. Durnell: 7–2 for Monsanto; described as preventing state-court failure-to-warn suits.
  • Monsanto's insurers contributed to the $550m cash payment in the 2003 Anniston settlement.
  • EcoWatch reports settlements of $550–650m with cities through 2020 and a 1969 Monsanto PCB committee statement that there were too many customers and too much Monsanto profit to withdraw.
  • Roundup herbicide segment sales were €1.155bn in the third quarter of 2025 alone; the product has been on sale since 1974.
  • Bayer's dividend has been the legal minimum of €0.11 since 2024; the company reported a net loss of €3.62bn in 2025.
  • The International Agency for Research on Cancer's 2015 classification of glyphosate as 'probably carcinogenic' stands.
  • A Johnson award was reduced from $289.2m to $78.5m and then to $20.5m (the sources reviewed list it among glyphosate verdicts).
  • Jeffrey Ubben, a director of WWF-US, was also a director of ExxonMobil (2021–2026) and of Bayer AG (since April 2024).
  • Bayer AG is listed among the 17 corporate members of the TNFD Taskforce.

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: 2020–2026. All figures cover the same period. * Estimate built from cited figures.

Responses on record

  • bayer (December 2025): Sued AIG in St. Louis County, Missouri, for cover of PCB and Roundup settlements after payment demands in July and October 2024. · News Tribune
  • aig (2024–2025): Declined to cover the PCB and Roundup settlements; its grounds are not public and no defence filing was found. · News Tribune
  • bayer (24 June 2020): Announced agreements to resolve major legacy Monsanto litigation and stated there was no admission of liability. · Bayer
  • bayer (17 February 2026): Announced a proposed Roundup class settlement of up to $7.25 billion. · Bayer
  • bayer (25 June 2026): Issued a press release headed 'Monsanto wins landmark Roundup case at US Supreme Court'. · Bayer

In court and with insurers

Every proceeding and every insurer decision on record.

Lawsuits and rulings

  1. 2025-12–Ongoing
    Bayer / Monsanto v. AIG (excess policies, PCB and Roundup settlements)
    Court in St. Louis County, Missouri · Civil · Bayer / Monsanto → AIG

    Bayer seeks cover under excess policies running June 1967 to April 1986 for more than $1.9bn of PCB settlements (to end-2024) and more than $10bn of Roundup settlements. Payment demands were sent in July and October 2024. The insurer's grounds are not public. News Tribune

  2. 2026-06-25Defendant won
    Monsanto v. Durnell
    US Supreme Court · Civil · Durnell (plaintiff in the underlying Roundup case) → Monsanto

    The Court ruled 7–2 for Monsanto; a law-firm summary says state-court failure-to-warn suits are prevented under the federal pesticide law. Bayer

  3. 2026-02-17–Ongoing$7.25bn USD million, up to, over up to 21 years
    Roundup class settlement (proposed)
    not on record · Class action · Roundup claimants (class) → Monsanto / Bayer

    Bayer announced a proposed class settlement of up to $7.25bn paid over up to 21 years; about 65,000 claimants in Roundup cases; litigation provisions rose to €11.8bn. Bayer

  4. 2020Settled$650m USD million, up to; reported range $550–650 million, through 2020
    PCB claims by cities against Monsanto
    Court not on record · Civil · Cities (EcoWatch headline refers to California cities) → Monsanto

    EcoWatch reports settlements with cities of $550–650 million through 2020. EcoWatch

  5. 2003Settled$550m USD million, cash payment
    Anniston PCB settlement
    Court not on record · Civil · not on record → Monsanto

    Settlement of 2003 including a $550m cash payment to which Monsanto's insurers contributed.

Insurers

  1. 2025In litigation
    AIG → Monsanto / Bayer
    Stated reason: Grounds not public

    AIG declined to cover PCB settlements (more than $1.9bn by end-2024) and Roundup settlements (more than $10bn) after payment demands in July and October 2024. Bayer sued in St. Louis County, Missouri, in early December 2025 under excess policies from June 1967 to April 1986. The case was pending. News Tribune

  2. 2003Partly paid
    Monsanto's insurers (not named in the sources reviewed) → Monsanto

    Monsanto's insurers contributed to the $550m cash payment in the 2003 Anniston settlement.

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.

AIG's stated grounds
Not public
AIG declined the 2024 payment demands; the filing was reported in December 2025.
Settlements in dispute
>$1.9bn / >$10bn
PCB and Roundup settlements to end-2024, as reported
Roundup litigation at the Supreme Court
7–2 for Monsanto
Monsanto v. Durnell, 25 June 2026

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.

Accounts

  • Disputed Is AIG obliged to cover the PCB and Roundup settlements?
  • Disputed Can Roundup users bring state-law failure-to-warn claims?

Record

  • None on record AIG's grounds for refusing to cover the PCB and Roundup settlements are not public; no insurer defence was found in the sources reviewed.
  • Insufficient Reported but not independently verified: reports of News Tribune and DTN reports say the complaint calls the insurers' grounds 'meritless excuses and purported defenses'.
  • Insufficient Reported but not independently verified: King County (Washington) juries in the Sky Valley school cases awarded punitive damages against Pharmacia/Monsanto (for example $75 million in one case); the 2002 Anniston jury findings were not re-verified.
  • Insufficient Reported but not independently verified: a National Union v. Everest reinsurance dispute over a 2004 Monsanto environmental settlement was still unresolved in 2015.
  • None on record An earlier survey of the sources reviewed found no record of insurance contributions to the Roundup and dicamba settlements, which were private settlements; none of the coverage sources documented revenue or profit from the activity.

Did the harm stop?

the sources reviewed give that Roundup stayed on sale after the settlements: the herbicide segment sold €1.155bn in the third quarter of 2025 alone, and the product has been on sale since 1974.

Who paid?

Bayer paid the settlements from company funds and sought cover from AIG in December 2025. the sources reviewed record the dividend at the legal minimum since 2024 and a €3.62bn net loss in 2025.

Sources

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

Government and regulators

  1. ExxonMobil 2026 proxy statement (director biographies)
    US Securities and Exchange Commission filing · 2026

Press and investigations

  1. Supreme Court decides Monsanto v. Durnell
    Faegre Drinker (law firm) · 2026-06

Standard-setters and registries

Connected cases

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

Law and courts

Class action
A single lawsuit brought on behalf of a large group of people with similar claims.
Punitive damages
Money a court orders a defendant to pay to punish especially reckless conduct, on top of compensation for losses. Mainly used in US courts.

Institutions

EPA
The US Environmental Protection Agency.

Insurance

Reinsurance
Insurance bought by insurers to pass part of their own risk to other companies.

Science and environment

PFOA (C8) and PFAS
PFAS are a large family of human-made chemicals that persist in the environment and the body; PFOA, also called C8, is one of them and was used to make Teflon.