Environmental research often focuses on the event itself: a spill, a war, an industrial operation, a development project, a disaster.

Residuals begins afterward.

We are interested in the period when attention has moved elsewhere but the material has not.

A metal fragment corrodes.

A chemical binds to sediment.

A shoreline continues responding to a decision made decades earlier.

An abandoned munition slowly changes in soil.

A contaminant enters a food web.

A landscape quietly becomes an archive.

These processes can unfold over years, decades, centuries, or longer.

Understanding them requires looking beyond the event and following the material.

Military activity produces physical legacies that can remain long after operations or conflict have ended.

Our research examines the environmental persistence of metals, munitions constituents, petroleum products, chemical residues, unexploded ordnance, and other military-derived materials in soils, sediments, waters, ecosystems, and landscapes.

Landscapes retain evidence.

Environmental forensics allows us to reconstruct where materials came from, how they changed, where they moved, and what processes continue to control them.

Chemical signatures, historical records, spatial patterns, corrosion, sediment, and fragments of material can all become evidence.

Human decisions can remain visible in landscapes long after the infrastructure, engineering project, or policy that created them has disappeared.

Historical maps, aerial imagery, GIS, shoreline reconstruction, and ecological measurements allow us to examine how those decisions accumulate through time.

Residual contamination is also a question of inheritance.

The people and ecosystems experiencing an environmental legacy are often not the people who created it.

We are interested in how environmental consequences move across generations, political boundaries, ecosystems, and communities, and how societies decide what responsibility remains when the original event is already history.

Residuals works across disciplines because environmental legacies rarely belong to only one.

We combine:

Environmental science to understand the behavior of materials in natural systems.

Environmental forensics to identify sources and reconstruct contamination histories.

Geospatial analysis to examine how landscapes change through space and time.

Historical research to understand the events and decisions that produced environmental residues.

Data analysis to identify larger patterns across cases.

Narrative storytelling to make those processes understandable beyond scientific journals.

The result is an approach that treats landscapes not simply as places where history happened, but as physical records of it.

A central idea behind our work is the Residual Cascade:

EVENT → MATERIAL → STORAGE → ALTERATION → TRANSPORT → EXPOSURE → INCORPORATION → INHERITANCE

An event produces or releases material.

That material enters an environmental system.

It may be buried, dispersed, dissolved, corroded, transported, consumed, incorporated into organisms, or inherited by future landscapes and communities.

The original event may last minutes.

The cascade may continue for centuries.

A narrative nonfiction project exploring how the material consequences of human activity remain active long after the events that created them have ended.

Environmental forensic research examining the metallic and chemical remnants of twentieth-century warfare preserved in the volcanic sands of Iwo Jima.

A quantitative research project examining how warfare-derived contaminants persist, move, transform, and enter biological systems across conflict landscapes around the world.

A historical and geospatial reconstruction of nearly two centuries of wetland transformation in Mission Bay, California.

An initiative focused on the long-term environmental consequences of conflict, contamination, militarization, and other human disturbances.

Carrie A. Shuster is an environmental scientist, researcher, author, and U.S. Navy veteran whose work examines how human systems continue to shape landscapes long after their visible activities have ended.

Her research combines environmental science, environmental forensics, geospatial analysis, historical reconstruction, and quantitative methods to study the environmental legacies of warfare, contamination, land-use change, and human disturbance.

Her work on the black sands of Iwo Jima investigates the persistence of military-derived metals and material fragments decades after the Second World War. Other research examines long-term wetland transformation in Mission Bay and broader patterns in the environmental persistence and movement of warfare-derived contamination.

Before becoming an environmental scientist, Shuster served in the United States Navy working with F/A-18E/F Super Hornet aircraft. That experience later became part of a much larger scientific question: what happens to the enormous quantities of materials used by human systems after their immediate purpose has ended?

Residuals grew from that question.

Modern societies are very good at identifying beginnings and endings.

Wars have ceasefires.

Facilities close.

Projects are completed.

Equipment is retired.

Sites are abandoned.

Records are archived.

But environmental systems do not necessarily recognize those boundaries.

Matter continues reacting.

Landscapes continue changing.

Contaminants continue moving.

The past remains physically present within the future.

Understanding that persistence may change how we design, regulate, remediate, wage war, restore landscapes, and think about responsibility itself.