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The report finds that while most US states meet the minimum legal requirements for Title V air permitting notices, there are substantial gaps in transparency, accessibility, and the actual influence of public input on final decisions. It highlights that many public notices are written at a college reading level and lack plain language, and that few agencies transparently report how public comments shape permit outcomes. The analysis suggests that states with specific environmental justice or cumulative impacts laws tend to have better engagement practices. It recommends that agencies adopt plain language, provide multilingual resources, and establish clear mechanisms for reporting how community input affects regulatory decisions.

California state legislators are calling on their federal representatives to oppose 13 Congressional Review Act (CRA) resolutions aimed at overturning state emissions standards. The legislators argue that revoking the Advanced Clean Cars I (ACCI) and Small Off-Road Engines (SORE) programs would increase air pollution, jeopardize public health in frontline communities, and risk billions of dollars in federal highway funding by undermining California's ability to meet National Ambient Air Quality Standards (NAAQS). They highlight that the state's air quality is already critical, with six of the ten most ozone-polluted cities in the U.S. located in California.

The Union of Concerned Scientists (UCS) developed an evolved methodology to track 'attacks on science'—defined as political interference in federal science—starting in January 2025. The system combines automated R scripts for RSS feed collection and keyword filtering with human content analysis to categorize attacks by type, topic, and stage of completion. The methodology aims to systematically capture a comprehensive breadth of attacks in perpetuity, including those that are only threatened, to document their chilling effects on the federal scientific enterprise.

The Union of Concerned Scientists (UCS) conducted a qualitative thematic analysis of 92 public comments submitted to the US EPA regarding its November 2024 Cumulative Impacts Framework. This process involved five coders who identified five primary themes and subthemes, utilizing NVivo software and Gwet’s AC1 scores to ensure inter-rater reliability. To validate these findings, UCS held four virtual 'ground-truthing' convenings between February and May 2026 with 18 experts and community members. The analysis was prompted by the second Trump administration's actions since January 2025, which the report states have undermined the EPA's ability to use the Framework and ignored public comments.

The Union of Concerned Scientists (UCS) reviewed 107 unique documents from 2,984 public comments regarding the EPA's 2024 Cumulative Impacts (CI) Framework. The analysis identifies five core themes for a robust CI program: legal authority, program execution, community engagement, assessment methodology, and ensuring outcomes. The report notes that the second Trump administration has undermined these efforts by rescinding environmental justice executive orders, disbanding advisory councils, and eliminating the EPA's Office of Environmental Justice and External Civil Rights.

The report synthesizes interviews with 25 climate litigation practitioners to identify critical gaps in scientific evidence needed for legal accountability. It highlights ten research priorities, including advances in end-to-end attribution science, quantification of noneconomic loss and damage, and the impact of industry disinformation. The authors also detail barriers to integrating science in courts, such as the 'resource imbalance' between public-interest lawyers and industry defendants, the differing standards of 'certainty' between science and law, and political interference in the judiciary.

Research by the Union of Concerned Scientists and University of California, Merced, indicates that emissions from the 'Carbon Majors'—the 122 largest industrial carbon producers—are responsible for approximately half of the climate-driven reductions in snowpack and streamflow, and increases in irrigation demand across the western United States. The analysis highlights specific 'hot spots' in California and the Pacific Northwest, noting that these emissions contributed to a 15% reduction in April snowpack and a 6.1% decrease in warm season streamflow. In California's Central Valley, 10% of observed groundwater loss is attributed to these companies. The document argues that the fossil fuel industry should be held financially accountable for these damages, as local governments and vulnerable communities currently bear the economic costs of adaptation and infrastructure failure.

A study by the Union of Concerned Scientists and UC Merced finds that human-caused climate change has significantly reduced snowpack and streamflow while increasing irrigation demand in the western US. Approximately half of these impacts are attributed to the emissions of 'Carbon Majors'—the 122 largest industrial CO2 emitters. The report highlights severe consequences in agricultural regions like California's Central Valley, where Carbon Majors' emissions are linked to 10% of groundwater loss, and argues for the financial accountability of these companies for climate-driven water damages.

The Union of Concerned Scientists claims that We Energies and independent power producers in Wisconsin are separating the construction and power acquisition review processes to avoid considering community needs when approving new gas plants. The author asserts that this 'ruse' prevents public debate on power sources and calls for legislators to implement long-term energy planning requirements to prevent regulators from reviewing interrelated cases in silos.

The Union of Concerned Scientists (UCS) guide outlines four policy priorities for the August 2026 congressional recess: supporting the Scientific Integrity Act, funding climate-disaster agencies (NOAA and FEMA), opposing legal immunity for fossil fuel companies via the Stop Climate Shakedowns Act of 2026, and addressing the energy affordability crisis. It provides tactical instructions for delivering petitions, using social media, and questioning representatives at town halls to counter perceived attacks on science by the Trump administration.

The brief contends that removing Civil Service Reform Act (CSRA) protections for federal employees with policymaking or administrative responsibilities would allow the Trump Administration to fire scientists based on political disagreement rather than merit. It argues that independent science is a statutory requirement for agencies like the EPA, CDC, and HHS to faithfully execute laws related to air quality, chemical safety, and vaccinations. The authors provide case studies on the Clean Air Act, ethylene oxide regulation, mRNA vaccine development, and hepatitis B vaccinations to demonstrate how political interference in science endangers public health and safety.

The Union of Concerned Scientists (UCS) advocates for the Scientific Integrity Act to codify protections for federal science, citing a significant increase in 'attacks on science' and the undermining of previous integrity policies by the second Trump administration.

The executive summary advocates for local 'behind-the-meter' solar and storage in Massachusetts as a means to protect environmental justice (EJ) communities from the health and financial burdens of gas-fired power plants and extreme weather. It notes that over 80 percent of the state's polluting power plants are located in or near EJ neighborhoods and proposes 18 recommendations to scale these clean energy solutions.

The report highlights that over 66 million people in the US live near freight facilities, with higher concentrations of warehouses linked to increased cancer risks and air pollution. It advocates for Indirect Source Rules (ISRs), which require facilities to mitigate the 'indirect' emissions they attract, citing California's WAIRE program as a successful model for increasing zero-emission vehicle adoption and infrastructure.

The Union of Concerned Scientists (UCS) developed a spatial analysis using dasymetric mapping and source-specific buffers to quantify population exposure to freight pollution in the contiguous US. The research found that over 66 million people live near freight facilities and corridors, with higher concentrations of facilities strongly correlating with increased cancer risk, diesel particulate matter, and social inequities. To address this, the document reviews indirect source rules (ISRs), which require facilities to mitigate the pollution attracted by their operations through options such as zero-emission vehicle deployment, charging infrastructure, and on-site renewable energy.

The report identifies that over 66 million people in the U.S. live near freight facilities and corridors, with those near clusters of 11 or more facilities facing a 32% higher cancer risk from air toxics than the national average. It advocates for Indirect Source Rules (ISRs), which require facilities to mitigate the pollution attracted by their operations, as a tool to address these disparities. The author details best practices for ISR design and proposes various compliance options, including the deployment of zero-emission vehicles, charging infrastructure, and innovative solutions like using wastewater treatment plant methane for port power.

The document examines the surge in data center demand in California, driven by generative AI, and warns that without new statewide policies, this growth could increase electricity costs for ratepayers, delay the clean energy transition, and threaten grid reliability. It highlights the risks of fossil-fueled backup generators on local air quality and recommends that data centers pay for their own clean energy generation and grid connection costs.

The fact sheet asserts that a small number of fossil fuel corporations are primarily responsible for climate change, having known about the dangers of their products since the 1950s but choosing to mislead the public and lobby against climate action to maintain profits. It highlights that legal action is currently being taken by various US jurisdictions to hold these companies accountable for deceptive practices and climate damages.

The document outlines technical adjustments made to the ReEDS database for a study on data center threats in Louisiana. Key modifications include restricting wind power deployment in Louisiana until 2029 due to slow growth and interconnection delays, and updating retirement dates for several coal and gas plants in Louisiana and Arkansas to reflect current utility filings and legal settlements.

The Union of Concerned Scientists (UCS) warns that Louisiana's current regulatory trajectory could lead to up to $26 billion in electricity system costs and $3 billion in public health damages between 2026 and 2041 due to data center growth. The report highlights a systemic overreliance on fossil gas, which is projected to peak in 2038, and criticizes the Louisiana Public Service Commission (LPSC) for a lack of transparency and inadequate ratepayer protections, specifically citing the 'Lightning Amendment' and the Entergy/Meta project as examples of risky policy. UCS recommends reforming the Integrated Resource Planning (IRP) process, implementing standardized tariffs for data centers, and expanding wind, solar, and grid connectivity to reduce costs and emissions.