The Ten Agents of Deterioration are one of the most widely used frameworks in preservation. Most people working with collections have encountered them in some form, including water, light, pests, and other common risks. For readers who are new to the framework or looking for a refresher, this fun video series, The Agents of Deterioration is a helpful introduction to each of the agents.
But knowing the list is not the same as recognizing risk in your own building. During a risk assessment walkthrough, the focus is less on abstract categories and more on identifying small, concrete signs and conditions that suggest where collections may be most vulnerable.
What follows is not a definition of the 10 agents. Instead, it is an overview of what they often look like in real collections spaces.
Water
Water is one of the most common risks identified during collections walkthroughs. While active leaks or flooding events may not be present at the time of a visit, buildings and storage spaces often show evidence of recurring moisture issues or past water intrusion. Even spaces that appear dry can contain indicators that point to increased vulnerability during heavy rain, plumbing failures, seasonal moisture changes, or future building maintenance issues.
Walkthrough indicators:
- Staining on ceiling tiles, walls, or shelving
- Pipes with active drips, condensation, or corrosion
- Water lines or tide marks on walls and floors
- Downspouts discharging too close to the building foundation
- Damp or musty odors in storage areas
- Evidence of past leaks, even if repairs have already been made
Collections indicators:
- Warped or cockled paper
- Mold staining or inactive mold residue
- Tidelines or water staining on boxes and enclosures
- Distorted photographs or adhered materials
Temperature
Temperature issues in collections spaces are often identified through both the environment itself and the condition of the materials stored there. During a walkthrough, unusually warm or cold spaces may immediately stand out, but there are often additional indicators that suggest long-term exposure to elevated or fluctuating temperatures. While short-term fluctuations may not cause immediate visible damage, long-term exposure to elevated or inconsistent temperatures can accelerate chemical deterioration and shorten the lifespan of many collections materials.
Walkthrough indicators:
- Storage areas that feel noticeably warmer or colder than surrounding spaces
- Collections stored in attics, near exterior walls, or in uninsulated rooms
- Space heaters or portable air conditioners in use near collections
- HVAC vents blowing directly onto shelving or storage furniture
- Seasonal shutdowns or spaces with limited climate control
Collections indicators:
- Photographs sticking together or showing image deterioration
- Pressure-sensitive tape becoming brittle or overly tacky
- Book bindings becoming dry, brittle, or warped
- Plastic enclosures or audiovisual materials beginning to distort or giving off an odor
Relative Humidity
Relative humidity issues are often identified through a combination of environmental clues and physical changes to collections materials. High humidity can encourage mold growth, corrosion, and pest activity, while very low humidity can contribute to brittleness and mechanical damage. Fluctuating humidity levels can also place stress on collections as materials repeatedly expand and contract. Relative humidity problems are often tied closely to seasonal weather patterns, building insulation, HVAC performance, and airflow.
Walkthrough indicators:
- Condensation on pipes, windows, or walls
- Damp or musty odors in storage spaces
- Areas that feel stagnant or poorly ventilated
- Evidence of mold growth, either current or past
- Rusting metal shelving, fasteners, or cabinets
- Data loggers showing significant seasonal fluctuations
Collections indicators:
- Cockled or wavy paper
- Mold staining or inactive mold residue
- Warping or distortion of bound volumes or wooden objects
- Brittle paper or splitting leather bindings in excessively dry conditions
Light (Especially Over Time)
Light damage is often difficult to identify during a walkthrough because it develops gradually over time. Prolonged exposure to visible light and ultraviolet (UV) radiation can cause irreversible fading, discoloration, and weakening of many collections materials, particularly paper-based and photographic collections. Because light damage is cumulative and irreversible, even relatively low levels of exposure can become significant over time, especially for materials that remain on permanent or long-term display.
Walkthrough indicators:
- Framed items hanging in direct sunlight
- Exhibit areas with lights left on continuously
- Windows without shades or UV-filtering films
- Strong natural light exposure in storage or exhibit spaces
- No rotation schedule for light-sensitive materials on exhibit
Collections indicators:
- Fading inks or color photographs
- Yellowing or darkening paper
- Uneven discoloration where part of an object has been covered
- Brittle or weakened newspaper and low-quality paper
Pests
Pest activity is often identified through evidence left behind rather than through live insect or rodent sightings. During a walkthrough, even small signs of activity can help identify areas where collections may be vulnerable to damage or where monitoring and housekeeping practices may need improvement. Because many pests are attracted to dark, undisturbed spaces, storage areas with limited housekeeping or monitoring can be especially vulnerable.
Walkthrough indicators:
- Dead insects on windowsills, floors, or sticky traps
- Rodent droppings near walls or shelving
- Insect casings, webbing, or frass near collections materials
- Food or drink present in collections areas
- Open gaps around doors, windows, pipes, or utility penetrations
- Traps that are not regularly checked or documented
Collections indicators:
- Small holes or grazing damage on paper and photographs
- Damage to book cloth, leather, or adhesives
- Nesting materials found behind boxes or shelving
- Staining, debris, or odors associated with rodent activity
Physical Forces
Physical forces are among the most visible risks encountered during collections walkthroughs and are often closely tied to storage limitations, handling practices, and day-to-day use of collections and spaces. Physical damage can occur gradually through repeated handling and poor storage support, or suddenly during routine activities such as moving boxes, retrieving materials, or navigating crowded storage areas.
Walkthrough indicators:
- Overfilled or overpacked boxes
- Shelving that is bowed, unstable, or overloaded
- Fragile materials stacked without adequate support
- Oversized items stored upright without protection
- Boxes protruding from shelves or stacked too high
- Crowded aisles or storage layouts that make safe access difficult
Collections Indicators:
- Torn or creased paper
- Broken bindings or detached covers
- Bent photographs, maps, or oversized documents
- Abrasions or surface damage from handling and shifting storage
Pollutants
Pollutants in collections environments can come from both external and internal sources and are often identified through gradual buildup or long-term exposure patterns. During a walkthrough, dust accumulation is one of the most visible indicators, but pollutants may also originate from building systems, storage materials, or nearby activities. While dust is sometimes viewed as a housekeeping issue, it can contribute to abrasion, attract moisture, support mold growth, and introduce contaminants to collections surfaces.
Walkthrough indicators:
- Dust buildup on shelves, boxes, and collections materials
- Storage near vents, workshops, or high-traffic areas
- Soot, grime, or particulate buildup near windows or air returns
- Strong chemical or musty odors in storage spaces
Collections indicators:
- Surface grime or embedded dust on paper and photographs
- Yellowing or discoloration of paper and enclosures
- Corrosion on metal fasteners or photographic materials
- Sticky or deteriorating plastics and adhesives
Fire
Fire risks identified during a walkthrough are often related to building systems, electrical infrastructure, housekeeping practices, and emergency preparedness measures rather than to collections materials themselves. Even in buildings with fire detection and suppression systems, walkthroughs can help identify conditions that may increase fire risk or complicate emergency response. Because fire can result in widespread and irreversible loss, identifying potential hazards and reviewing emergency systems and procedures are important components of collections risk assessment and long-term planning.
Walkthrough indicators:
- Absence of smoke detection or fire suppression systems in collections areas
- Fire extinguishers that are blocked, expired, or difficult to access
- Extension cords or overloaded electrical outlets in regular use
- Aging electrical infrastructure or exposed wiring
- Storage furniture placed too close to heat sources or electrical equipment
Theft & Vandalism
Risks related to theft and vandalism are often tied to access, security practices, and collections documentation. During a walkthrough, the focus is typically less on dramatic theft scenarios and more on identifying vulnerabilities that could allow collections to be damaged, removed, or misplaced without being noticed. Strong documentation and clear access procedures are important parts of collections security, as it can be difficult to identify loss or determine when and where damage occurred without reliable tracking and oversight.
Walkthrough indicators:
- Unlocked or unsecured storage areas
- Keys or access codes that are widely shared or not tracked
- Public or unsupervised access to collections spaces
- Limited inventory or location tracking documentation
- Materials left unattended in workspaces or reading rooms
- Missing labels, detached identifying information, or evidence of undocumented movement
Dissociation
Dissociation refers to the loss of information that connects collections materials to their context, meaning, or location. Unlike many other agents of deterioration, dissociation may not involve visible physical damage, but it can significantly reduce the research, interpretive, and historical value of collections. Because dissociation can occur gradually over time through staff transitions, inconsistent documentation, or informal workflows, it is one of the most common risks identified during collections assessments.
Walkthrough indicators:
- Unlabeled boxes, folders, or shelving areas
- Items separated from accession numbers or identifying information
- Backlogs in cataloging or processing
- Inconsistent or fading labels; labels that are unsecured or falling off
- Digital files with unclear or duplicated file names
- Collections locations known primarily through staff memory
From Observation to Action
A walkthrough helps identify where risks may exist within collections spaces, but a risk assessment takes that process one step further by helping institutions evaluate and prioritize those risks. In many cases, the goal is not to address every issue immediately, but to better understand which conditions pose the greatest concern and where limited time and resources can have the most impact.
Risk assessment often focuses on questions such as:
- Which risks are most likely to occur
- Which would have the greatest impact on collections
- Which issues affect the largest portions of the collection
- What can realistically be addressed in the short and long term
Just as importantly, walkthroughs can help identify positive conditions and existing preservation practices that may already be reducing risk. Even small changes to storage, housekeeping, environmental monitoring, or documentation practices can meaningfully improve collections care over time.
By moving from observation to prioritization, risk assessment helps institutions develop practical, manageable next steps that align with their building, staffing, budget, and collections needs.
Learn More
For institutions interested in applying these concepts to their own collections spaces, DHPSNY offers upcoming webinar and workshop opportunities focused on risk assessment.
Introduction to Risk Assessment for Cultural Collections
This free, one-hour webinar provides an introduction to risk assessment concepts for cultural collections. Participants will explore common sources of deterioration, how to evaluate vulnerability, and how risk assessment can support more informed preservation decision-making. The session is designed as an accessible starting point for institutions looking to develop a more proactive approach to collections care.
Understanding Risk to Protect Collections
DHPSNY’s free, full-day workshop expands on these ideas through guided exercises, real-world examples, and hands-on risk assessment activities. Participants practice identifying agents of deterioration, evaluating risk in collections spaces, and developing practical preservation priorities based on institutional needs and available resources. The workshop will be offered at four locations across New York State. Registration is now closed for Buffalo and Waterville, but space is still available at the Schenectady and New York workshops.
Do you have a preservation topic, question, or creative solution you would like us to cover in this series? Reach us by email at info@DHPSNY.org, or connect with us on the DHPSNY Facebook page or DHPSNY Community Facebook Group.