This article explains the difference between an environmental hazard and actual risk levels to building occupants from such hazards.

Making this less-than-obvious distinction between hazard and risk can help us decide when and how to spend money managing or addressing environmental and other hazards found in, on, and around buildings and their mechanical systems.

Why Distinguish Between of Hazard vs Environmental Risk

Across many building, mechanical, structural, and environmental hazards discussed in articles found at InspectApedia.com, the most common concerns expressed by our readers are

1. How dangerous is something scary that I've found in my building or read about somewhere?
2. What should I do or spend on fixing this concern?
3. How quickly should I take action?

Safety, environmental and health experts have for some time made an important distinction between hazard and risk that, until it has been explained, is not obvious to the rest of us.

Photo: we found these drums used to store toxic chemicals at the site of a home inspection in New York.

[Click to enlarge any image]

Hazards at Buildings

If a substance or building condition is called a hazard, that simply means that there is a potential for harm. For example, experts have said that asbestos is a hazardous material and a potential carcinogen.

But that statement doesn't tell us anything about the specific level of actual risk of harm at a specific building where asbestos might be present.

Risks at Buildings

Unlike hazards just mentioned above, some safety and health experts refer to risk as the probability of and severity of harm (to building occupants or perhaps to the building itself, depending on what issue is being discussed).

In a discussion of the relationship between food safety and health, Clemens et al (2016) put it this way:

... it is important to remember a simple acronym, RITE (Risk Is Toxicity x Exposure)

The authors point out that some things that people are very worried about actually produce no plausible risk [we add that] while others can be very high risk and deserve prompt action.

An example is found in U.S. EPA and other authorities' advice about non-friable asbestos materials. Although asbestos is hazardous, asbestos materials that are not shedding or releasing asbestos dust into the occupied space and that are being left undisturbed are hazardous but do not present a meaningful risk to building occupants.

We'd add that other concerns we may find at, in, or on a building might pose a very high risk even if they're not the first thing that catches our attention.

For example, falling down the stairs is one of the most common hazards in buildings.

Why is the Difference between Hazard and Risk Important?

Clearly we don't have an endless supply of money, time, and attention, and because we need to make rational decisions about when to expend those on addressing a concern at a building, it is essential to consider risk, not just hazard.

If we fail to consider risk, we can spend enormous amounts of time and money on the wrong problem at buildings.

As we summarized above, health and environmental professionals point out that in assessing the actual risk of harm from a hazardous material such as an environmental contaminant or unsafe building material (asbestos, lead paint, pesticides, etc.) the actual risk depends on

• the toxicity of the material or substance
• the level of exposure of people to the substance or material
  
  (this includes both how much material is present and the duration and other factors that affect the level of exposure such as temperature, exposure pathway such as skin, breathing, etc.)

But for many building materials or conditions that involve hazardous materials or substances as well as risk of health or economic harm, we can make a simpler analysis: how serious is this problem, what sorts of harm are involved, and how urgently should we act?

Example 1: don't let a low-risk or remote hazard cause you to ignore a close and immediate hazard that is high-risk

Above: a reader's measurement of magnetic field strength.

A home buyer was extremely worried about and planned to spend a significant sum investigating whether or not the electromagnetic fields from overhead power lines a mile away were going to cause injury to the home occupants. The strength of EMF falls off as the square of the distance, so his EMF measurement "under the power line" did not give a useful indication of the risk closer to his home.

Yet he was so frightened that he was planning to install expensive (and ineffective) EMF shielding around the home.

But during the inspection we found stairs that had tall, rotting, uneven stair treads along a stairway with no handrails, an FPE electrical panel whose circuit breakers are known to fail to protect from fire and over-current at a significant rate, an unsafe chimney venting heating furnace that was back-drafting flue gases and potentially fatal carbon monoxide into the home, and a return air inlet right at the furnace, and several more immediate functional and safety concerns.

Our opinion was that even before considering the vulnerability of the building occupants or the duration of their exposure, the risks from those findings were far greater than the distant overhead electrical power lines.

See BACKDRAFTING HEATING EQUIPMENT

and compare those hazards to

EMF CANCER RISK from distant power lines.

Perspective on Risk of Injury or Death

The top three leading causes of preventable injury-related death – poisoning, motor vehicle, and falls – account for over 86% of all preventable deaths. No other preventable cause of death—including suffocation, drowning, fires and burns, and natural or environmental disasters—accounts for more than 5% of the total. - U.S. National Safety Council, To 10 Preventable Injuries (2023)

Similarly, The U.S. CDC, reporting on Top Ten Leading Causes of Death in the U.S. for Ages 1-44 from 1981-2020 notes that

• Unintentional injuries are the leading cause of death for Americans aged 1-44 years old.
• Unintentional injuries include opioid overdoses (unintentional poisoning), motor vehicle crashes, and unintentional falls.
• Suicide is now the 2nd leading cause of death for this 1-44 age group, and numbers of suicides continue to rise.
• Homicide remains in the top 5 leading causes of death for the 1-44 age group.

Example 2: Don't Confuse a No-Exposure or Insignificant Exposure that Doesn't Merit Action with a Significant Exposure Hazard & Risk

At ASBESTOS PIPE INSULATION a reader asked:

Is a small hairline dent worrisome on a asbestos plaster on pipe? - Anonymous 2023/09/01

We replied:

If your "small hairline dent" is the same as my idea of that sort of damage, my answer would be no.

Put another way, if asbestos- or asbestos-suspect pipe insulation is undamaged, that is, it's not shedding insulating material, then it's not releasing a meaningful enough amount of material to be considered a risk, even though asbestos itself is a hazardous material.

In contrast, the asbestos pipe insulation in the photo below is a hazard. Anyone who has to work in this space, say repairing a leaky pipe, faces a significant asbestos exposure risk because it's so difficult to move in the area without disturbing this friable material.

And there is additional risk that workers or building occupants track this friable asbestos insulation into the occupied spaces of the building as well.

When is the Building In Control of Your Money?

Dan's 3-Ds

When a building occupant or owner has been told that repairs or corrections are needed, it's important that we ask "who's in control of our money and time, us or the building?". As a home inspector, I [DF] made up this gimmicky reply, the 3 Ds, to help remember my opinion and answer.

Setting priorities for building repairs:

Here are the classes of findings which deserve highest priority of attention. This little list can help the inspector and the inspector's client sort through the large volume of clues and "findings" that will be produced by any careful inspection of a building.

[Click to enlarge any image]

More Urgent Building Repairs or Improvements

For the following three items, the 3 Ds, the "building is in control of the client's money" in the sense that items in all three categories really need to be addressed promptly.

1. Things at, in, or on a building that are Dangerous 

Photo above: overheating wires at an FPE electrical panel - high risk of setting the building on fire.

Details at FPE FAILURE FIRE PHOTOS

Examples:

• Watch out: If you see or smell smoke or a gas leak: get out of the building and from a safe distance call emergency services such as #911.

• If sparks are coming out of your electrical panel or wall receptacles or switches, turn off power if you can do so safely, then call for repair.
• A less immediate but serious danger might be an unsafe electrical panel whose circuit breakers are known to not trip in response to an over-current, such as FPE electrical panels.
• If there is the slightest doubt about the condition of the septic tank cover or if it is missing, you should rope off the area and prevent anyone from walking over it, because falling into a septic tank is likely to be fatal.
• Handrailings that are missing, not-graspable, too low, too high, or that are not securely fastened are dangerous and increase the risk of a fall. Be sure there is a handrail installed that is securely fastened and meets the proper code for size, location, and height.

2. Things at, in, or on a building causing rapid, costly Damage

Photo above: following a burst toilet tank that flooded this building, we moved wet rugs and mattresses outdoors and cleaned up water and all wet materials within 24 hours in order to avoid a mold contamination problem that would have been much more costly.

Photo below: a "worst case" example shows what happens if a building is wet by flooding and left unattended for weeks (owners were on vacation):

Examples:

• Leaks into building walls, ceilings, floors that are wetting drywall - can, in as little as two days, generate extensive mold contamination that is costly to remove (also a potential health hazard). Such leaks and other mold prevention steps need to be addressed promptly.
  
  See EMERGENCY RESPONSE, IAQ, GAS, MOLD
• In contrast, a dripping faucet that drips into a sink isn't an emergency repair but even that, in freezing weather, can lead to a frozen, burst drain line outdoors, so it needs to be repaired - but it's not an emergency.
• A failing septic system that is causing backups into the home risks water damage and odors. Inspection of the system must be completed to determine cause and any necessary repairs.

3. Things at, in, or on a building that are essential that Don't Work at all or don't work reliably enough.

Photo above: loss of heat led to frozen, burst water and heating pipes in this building, of course, leading to water damage, too.

Examples:

• If the building is in a climate exposed to freezing (that can cause frozen pipes and expensive damage) and the heating system either does not work at all, or does not work reliably enough that you can safely leave the building unattended during freezing weather, then in essence the heating system "doesn't work" and needs to be repaired promptly.
• Other things that don't work, like a light switch in your bedroom are dangerous but not an emergency repair.
• Appliances not working properly such as a gas range with only two working burners or a freezer that doesn't adequately freeze.

In the case of "Dan's 3 Ds" - Dangerous, causing rapid costly Damage, or Doesn't Work, the building is in control of your money, time, and attention: these items need to be addressed.

Less Urgent Building Repairs or Improvements

Other building repairs that are needed or improvements such as painting, new siding, landscaping, are examples of potentially significant costs for which the building owners or occupants are in control of when that money should be spent.

More about setting these priorities is at our article on building risk assessment

FEAR-O-METER

Research on Environmental Hazard vs Risk

• ANSI/AIHA Z-10-2005, "Safety management, The New Benchmark for Safety Management Systems", AIHA, retrieved 5/20.2014, original source: http://www.asse.org/publications/standards/z10/docs/25-33Feb2006.pdf
• American Industrial Hygiene Association, AIHA, "Compendium of Risk Assessment/Risk Management Resources", (2002), retrieved 5/20/2014, original source: https://www.aiha.org/get-involved/VolunteerGroups/Documents/ RISKVG-%28Attachment%20F%29%20Compendium%20of%20risk%20assessment- risk%20management%20resources.pdf
• American Industrial Hygiene Association, AIHA, "AIHA Position Statement on Risk Assessment and Risk Management ", (2002), retrieved 5/20/2014, original source: https://www.aiha.org/government-affairs/PositionStatements/position02_Risk.pdf
• American Industrial Hygiene Association, AIHA, "AIHA White Paper on Risk Assessment and Risk Management", (2002), retrieved 5/20/2014, original source: https://www.aiha.org/government-affairs/WhitePapers/whitepaper02_Risk.pdf
• Clemens, Roger, A. Wallace Hayes, and Claire Kruger. UNDERSTANDING THE DIFFERENCE BETWEEN HAZARD AND RISK [PDF] Food Technol-Chicago 70 (2016): 18-19
  
  Excerpts:
  
  A fundamental understanding of the risk assessment process, including differentiating between real risk and a perceived hazard is critical.
  
  To understand the hazard/risk relationships, there is a need to recognize four basic principles: dose matters, timing is critical, people differ, and things change.
• Doe, John E., Alan R. Boobis, Samuel M. Cohen, Vicki L. Dellarco, Penelope A. Fenner-Crisp, Angelo Moretto, Timothy P. Pastoor, Rita S. Schoeny, Jennifer G. Seed, and Douglas C. Wolf. "The codification of hazard and its impact on the hazard versus risk controversy." Archives of Toxicology 95 (2021): 3611-3621.
• NSC, TOP 10 PREVENTABLE INJURIES [PDF] (2023) U.S. National Safety Council, 1121 Spring Lake Dr. Itasca, IL 60143-3201 USA, Tel: (800) 621-7615 Email: customerservice@nsc.org Web: nsc.org/ - retrieved 2023/09/02, original source: https://injuryfacts.nsc.org/all-injuries/deaths-by-demographics/top-10-preventable-injuries/
• Nordin, BE Christopher, Peter A. Baghurst, and Andrew Metcalfe. "The difference between hazard and risk in the relation between bone density and fracture." Calcified Tissue International 80 (2007): 349-352.
• OSHA, HAZARD COMMUNICATION STANDARD: SAFETY DATA SHEETS [PDF] OSHA, Occupational Safety and Health Administration, www.osha.gov retrieved 2021/05/02 original source: https://www.osha.gov/sites/default/files/publications/OSHA3514.pdf
  
  Excerpts:
  The Hazard Communication Standard (HCS) (29 CFR 1910.1200(g)), revised in 2012, requires that the chemical manufacturer, distributor, or importer provide Safety Data Sheets (SDSs) (formerly MSDSs or Material Safety Data Sheets) for each hazardous chemical to downstream users to communicate information on these hazards.
  
  The information contained in the SDS is largely the same as the MSDS, except now the SDSs are required to be presented in a consistent user-friendly, 16-section format. This brief provides guidance to help workers who handle hazardous chemicals to become familiar with the format and understand the contents of the SDSs.
  
  Employers must ensure that the SDSs are readily accessible to employees for all hazardous chemicals in their workplace.
• Oyarzabal, Omar A., and Ellen Rowe. EVALUATION OF AN ACTIVE LEARNING MODULE TO TEACH HAZARD AND RISK IN HAZARD ANALYSIS AND CRITICAL CONTROL POINTS (HACCP) CLASSES [PDF] Heliyon 3, no. 4 (2017).
  
  Abstract excerpt:
  
  The terms hazard and risk are significant building blocks for the organization of risk-based food safety plans. Unfortunately, these terms are not clear for some personnel working in food manufacturing facilities.
• Roberts, Abby, "Communicating the Difference Between Hazard and Risk", in "PSX 2023: The Hub of Product Stewardship" The Synergist, September 2023, p. 20, AIHA, American Industrial Hygiene Association, www.aiha.com
  
  This brief article describes the content of an upcoming session at the 2023 PSX Conference scheduled for 18 October 2023 in Boston, MA. That session is
  
  Yang, Garnick & Massarsky (hosts) Session J2, "Understanding Hazard Versus Risk Nuances of Consumer Products."
• Roberts, Daniel. "Risk management of electrical hazards: Bridging the gap in understanding hazard versus risk." IEEE Industry Applications Magazine 19, no. 3 (2013): 21-26.
  Abstract:
  
  Most occupational health and safety (OHS) professionals understand the difference between hazard and risk. However, the distinction between these terms is not well understood in the electrical industry, where they are often used interchangeably.
  
  This gap in understanding between OHS and electrical professionals needs to be bridged to ensure that electrical hazards, and the risks arising from those hazards, are effectively addressed. The objective of this article is to clarify the difference between hazard and risk and explain how OHS risk management principles can be applied to electrical hazards.
• U.S. CDC, reporting on TOP TEN LEADING CAUSES OF DEATH IN THE U.S. FOR AGES 1-44 FROM 1981-2020 (2022) U.S. Centers for Disease Control, - retrieved 2023-09-02, origianl source: cdc.gov/injury/wisqars/animated-leading-causes.html
• US EPA, HEALTHY BUILDINGS, HEALTHY PEOPLE [PDF] (2001) U.S. Environmental Protection Agency , Office of Air and Radiation
  
  Introduction excerpt:
  
  The importance of the indoor environment to human health has been highlighted in numerous environmental risk reports, including the 1997 report of the Presidential and Congressional Commission on Risk Assessment and Risk Management.
  
  On average, we spend about 90 percent of our time indoors, where pollutant levels are often higher than those outside. Indoor pollution is estimated to cause thousands of cancer deaths and hundreds of thousands of respiratory health problems each year.
  
  In addition, hundreds of thousands of children have experienced elevated blood lead levels resulting from their exposure to indoor pollutants.
• US EPA, SAMPLING GUIDANCE for UNKNOWN CONTAMINANTS in DRINKING WATER [PDF] (2017) U.S. Environmental Protection Agency Office of Water (4601M) 1200 Pennsylvania Avenue, NW Washington, DC 20460 EPA-817-R-08-003
• Wang, Jiajun, Zhichao He, and Wenguo Weng. "A review of the research into the relations between hazards in multi-hazard risk analysis." Natural Hazards 104 (2020): 2003-2026.

...

Continue reading at FEAR-O-METER, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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HAZARD vs RISK at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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