Forks in the Road to Sustainable Chemistry

In “A Road Map for Sustainable Chemistry” (Issues, Winter 2024), Joel Tickner and Ben Dunham convincingly argue that coordinated government action involving all federal funding agencies is needed for realizing the goal of a sustainable chemical industry that eliminates adverse impacts on the environment and human health. But any road map should be examined to make sure it heads us in the right direction.

At the outset, it is important to clear misinterpretations about the definition of sustainable chemistry stated in the Sustainable Chemistry Report the authors examine. They opine that the definition is “too permissive in failing to exclude activities that create risks to human health and environment.” On the contrary, the definition is quite clear in including only processes and products that “do not adversely impact human health and the environment” across the overall life cycle. Further, the report’s conclusions align with the United Nations Sustainable Development Goals, against which progress and impacts of sustainable chemistry and technologies are often assessed.

The nation’s planned transition in the energy sector toward net-zero emissions of carbon dioxide, spurred by the passage of several congressional acts during the Biden administration, is likely to cause major shifts in many industry sectors. While the exact nature of these shifts and their ramifications are difficult to predict, it is nevertheless vital to consider them in road-mapping efforts aimed at an effective transition to a sustainable chemical industry. Although some of these shifts could be detrimental to one industry sector, they could give rise to entirely new and sustainable industry sectors.

As an example, as consumers increasingly switch to electric cars, the government-subsidized bioethanol industry will face challenges as demand for ethanol as a fuel additive for combustion-engine vehicles erodes. But bioethanol may be repurposed as a renewable chemical feedstock to make a variety of platform chemicals with significantly more value compared to its value as a fuel. Agricultural leftovers such as corn stover and corn cobs can also be harnessed as alternate feedstocks to make renewable chemicals and materials, further boosting ethanol biorefinery economics. Such biorefineries can spur thriving agro-based economies.

Another major development in decarbonizing the energy sector involves the government’s recent investments in hydrogen hubs. The hydrogen produced from carbon-free energy sources is expected to decarbonize fertilizer production, now a significant source of carbon emissions. The hydrogen can also find other outlets, including its reaction with carbon dioxide captured and sequestered in removal operations to produce green methanol as either a fuel or a platform chemical. Carbon-free oxygen, a byproduct of electrolytic hydrogen production in these hubs, can be a valuable reagent for processing biogenic feedstocks to make renewable chemicals.

Another untapped and copious source of chemical feedstock is end-of-use plastics. For example, technologies are being developed to convert used polyolefin plastics into a hydrocarbon crude that can be processed as a chemical feedstock in conventional refineries. In other words, the capital assets in existing petroleum refineries may be repurposed to process recycled carbon sources into chemical feedstocks, thereby converting them into circular refineries. There could well be other paradigm-shifting possibilities for a sustainable chemical industry that could emerge from a carefully coordinated road-mapping strategy that involves essential stakeholders across the chemical value chain.

Bala Subramaniam

Joel Tickner and Ben Dunham describe the current opportunity “to better coordinate federal and private sector investments in sustainable chemistry research and development, commercialization, and scaling” through the forthcoming federal strategic plan to advance sustainable chemistry. They highlight the unfortunate separation in many federal efforts between “decarbonization” of the chemical industry (reducing and eliminating the sector’s massive contribution to climate change) and “detoxification” (ending the harm to people and the environment caused by the industry’s reliance on toxic chemistries).

The impacts and opportunities at stake are no small matters. The petrochemical industry produces almost one-fifth of industrial carbon dioxide emissions globally, and is on track to account for one-third of growth in oil demand by 2030, and almost half by 2050. Health, social, and economic costs due to chemical exposures worldwide may already be more than 10% of global domestic product.

As Tickner and Dunham note, transformative change is urgently needed, and will not result from voluntary industry measures or greenwashing efforts. So-called chemical recycling (which is simply a fancy name for incineration of plastic waste, with all the toxic emissions and climate harm that implies), and other false solutions (such as carbon capture and sequestration) that don’t change the underlying toxic chemistry and production models of the US chemical industry will fail to deliver real change and a sustainable industry that isn’t poisoning people and the planet.

Government and commercial efforts to advance sustainable chemistry must be guided by and accountable to the needs and priorities of the most impacted communities and workers, and measured against the vision and platform contained in The Louisville Charter for Safer Chemicals: A Platform for Creating a Safe and Healthy Environment Through Innovation.

The 125-plus diverse organizations that have endorsed the Louisville Charter would agree with Tickner and Dunham. As the Charter states: “Fundamental reform is possible. We can protect children, workers, communities, and the environment. We can shift market and government actions to phase out fossil fuels and the most dangerous chemicals. We can spur the economy by developing safer alternatives. By investing in safer chemicals, we will protect peoples’ health and create healthy, sustainable jobs.”

Among other essential policy directions to advance sustainable chemistry and transform the chemical industry so that it is no longer a source of harm, the Charter calls for:

• preventing disproportionate and cumulative impacts that harm environmental justice communities;
• addressing the significant impacts of chemical production and use on climate change;
• acting quickly on early warnings of harm;
• taking urgent action to stop the harms occurring now, and to protect and restore impacted communities;
• ensuring that the public and workers have full rights to know, participate, and decide;

• ending subsidies for toxic, polluting industries, and replacing them with incentives for safe and sustainable production; and
• building an equitable and health-based economy.

Federal leadership on sustainable chemistry that advances the vision and policy recommendations of the Louisville Charter would be a welcome addition to ongoing efforts for chemical industry transformation.

Steve Taylor

Joel Tickner and Ben Dunham offer welcome and long-overdue support for sustainable chemistry, but the article only scratches the surface of societal concerns we should have about toxicants that result from exposure to fossil fuel emissions, to plastics and other products derived from petrochemicals, and to toxic molds or algal blooms. Their proposals continue to rely on the current classical dose-response approach to regulating chemical exposures. But contemporary governmental standards and industrial policies built on this model are inadequate for protecting us from a variety of compounds that can disrupt the endocrine system or act epigenetically to modify specific genes or gene-associated proteins. And critically, present practices ignore a mechanism of toxicity called toxicant-induced loss of tolerance (TILT), which Claudia Miller and I first described a quarter-century ago.

TILT involves the alteration, likely epigenetically, of the immune system’s “first responders”—mast cells. Mast cells evolved 500 million years ago to protect the internal milieu from the external chemical environment. In contrast, our exposures to fossil fuels are new since the Industrial Revolution, a mere 300 years ago. Once altered and sensitized by substances foreign to our bodies, tiny quantities (parts per billion or less) of formerly tolerated chemicals, foods, and drugs trigger degranulation of mast cells, resulting in multisystem symptoms. TILT and mast cell sensitization offer an expanded understanding of toxicity occurring at far lower levels than those arrived at by customary dose-response estimates (usually in the parts per million range). Evidence is emerging that TILT modifications of mast cells explain seemingly unrelated health conditions such as autism, attention deficit hyperactivity disorder (ADHD), chronic fatigue syndrome, and long COVID, as well as chronic symptoms resulting from exposure to toxic molds, burn pits, breast implants, volatile organic compounds (VOCs) in indoor air, and pesticides.

Most concerning is evidence from a recent peer-reviewed study suggesting transgenerational transmission of epigenetic alterations in parents’ mast cells, which may lead to previously unexplained conditions such as autism and ADHD in their children and future generations. The two-stage TILT mechanism is illustrated in the figure below, drawn from the study cited. We cannot hope to make chemistry sustainable until we recognize the results of this and other recent studies, including by our group, that go beyond classical dose-response models of harm and acknowledge the complexity of multistep causation.

Nicholas A. Ashford