Photograph of chopped fiberglass insulation Fiberglass Hazards in Indoor Air, Dust, HVAC ducts, and Building Insulation

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Fiberglass hazards in buildings:

This article series provides information about how to identify fiberglass insulation in buildings and fiberglass hazards and fiberglass insulation contamination issues in residential and light-commercial buildings.

The fiberglass research literature is replete with studies indicating that there are no health hazards associated with airborne fiberglass particles, and with other studies reaching quite the opposite conclusion.

We recommend that readers examine carefully the methodology used in such studies, the expertise of the researchers, and the sources financing of such work.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

How to Identify or Recognize Fiberglass Insulation in buildings

Photo of fiberglass flex duct air conditioning ductworkHere we discuss the following: What does fiberglass building insulation look like & what are the colors of different brands of fiberglass insulation?

Where else do we find fiberglass in buildings besides floor, wall and attic insulation?

What are the Problems with Identifying Fiberglass Hazards in buildings? Microscopic identification of fiberglass insulation fragments,

Health concerns of fiberglass exposure, Mold hazards in fiberglass insulation,

Fiberglass exposure hazard reference list, Fiberglass insulation demolition mess, itching, dust persistence

[Click to enlarge any image]

Based on literature review as well as both field and laboratory experience, it is reasonable to claim that large particles of fiberglass are far more likely to be a respiratory or skin irritant than a carcinogen or other more serious health hazard.

However some of our field and lab inspections detect very small, even sub-micron sized particles which are traced to building insulation.

photo of yellow fiberglass building insulation

These much smaller particles may indeed be a health hazard, and may be entirely omitted or simply missed by some laboratories charged with reporting on the level of fiberglass in building air or dust.

photo of pink fiberglass building insulation

This article explains the recognition of types of fiberglass insulation in buildings, other fiberglass particle sources, and some possible health concerns that involve these materials.

What does fiberglass building insulation look like & what are the colors of different brands of fiberglass insulation?

photo of green fiberglass building insulation

Fiberglass building insulation is commonly installed in batts or chopped forms and may be yellow, pink, green, or white in color as is shown in these photographs.

photo of white fiberglass building insulation

While this material is not and should not be confused with asbestos nor with the well-studied health hazards associated with exposure to asbestos fibers or dust, our separate article on Airborne Fiberglass Building Insulation Hazards [link just below] and HVAC duct work insulation hazards contains additional discussion about possible air quality and health concerns which may be associated with exposure to fiberglass dust.


Where else do we find fiberglass in buildings besides floor, wall and attic insulation?

Fiberglass duct insulation material appears in several forms in heating and air conditioning systems in both ducts and air handlers themselves.

Photo of fiberglass flex duct air conditioning ductwork

The most common uses of fiberglass insulating material in HVAC systems includes the cases listed below.

The annotated duct system photographs shown in the article cited below will permit any careful observer to identify the most common types of fiberglass HVAC duct materials.

We provide these (C)-protected photographs of fiberglass insulated ducts and HVAC components to aid in recognition of these materials.

Our detailed article on how to recognize fiberglass duct insulation and its characteristics and hazards can be read in its entirety at FIBERGLASS HVAC DUCTS.

What are the Problems with Identifying Fiberglass Hazards in buildings?

photo of resin binder on fiberglass insulation fragments

Special challenges face consumers requesting lab services for identification of fiberglass fragments in air, dust, or material samples are easily identified in the forensic laboratory using light and polarized light microscopy and common slide preparation techniques.

Our photograph (left) shows a typical fiberglass insulation fiber with droplets of resin binder attached. It's easy to identify large fiberglass fibers in transmitted-light microscopy.

But identification of very small fiberglass fragments in a building dust or air sample can be difficult to detect unless the microscopist is trained and looking for that material, and special methods such as use of phase contrast may be needed.

Certainteed blown in fiberglass (C) Daniel Friedman

Binder Resins in Fiberglass Insulation Help Trace Source

Observing the color of a fiberglass bonding resin can help trace particular fiberglass in a building air or dust sample back to its source.

Other fiberglass products, such as this Certainteed un bonded blowing wool (fiberglass) lack a characteristic resin. Interestingly in this client-provided sample of nearly-new blown-in fiberglass insulation we found very few small fiber fragments. Dust tested from that home was also low in fiberglass fragments.

The common errors which result in failing to detect small fiberglass particles in building air and dust are discussed in detail at LAB IDENTIFICATION OF FIBERGLASS

In that article we also discuss techniques which permit the forensic microscopy lab to identify the source or reservoir of particular fiberglass fragments in a building, sorting out among many possible fiber sources to pinpoint the particular problem such as damaged building insulation, damaged HVAC duct work, or other particle sources.

We also discuss how to distinguish among types of insulating and other fibers, comparing various types of fiberglass insulation, mineral wool insulation, asbestos insulation, and other fibers.

Photograph of mold spores of Aspergillus sp. found in crawl space fiberglass insulation.

Frequent presence of fiberglass fragments in air and some dust samples, suggests that an HVAC duct system or exposed fiberglass insulation in the building may be contributing unwanted and potentially unsafe levels of these fibers. This discussion can be read in its entirety at FIBERGLASS DETECTION in BUILDING AIR & DUST.



Moldy fiberglass insulation

We have also detected high levels of problematic mold in fiberglass building insulation where other mold reservoirs were either not present or had been previously removed.

This article can be read in its entirety at MOLD in FIBERGLASS INSULATION

Reader Question: Continued Itching after Fiberglass Demolition

I have a question regarding fiberglass insulation. I pest control worker, who is trying to rid us of rats in the attic, removed the fiberglass insulation from the attic space but dragged the insulation through the house. Now, we are constantly itching. Is is due to fiberglass particles in the air?

What can we do? We've vacuumed a lot but it's not helping. Help! Thank you for your time, M & M.

Reply: clean up, wash, laundry clothing, check with your doctor, consider dust testing

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a problem such as incomplete cleaning, or some other problem source yet unnoticed, including a biological hazard associated with the rodents themselves.

In addition to consulting your doctor who may in turn decide to refer you to a dermatologist, you might also benefit from reviewing the ITCHING & SCRATCHING RESEARCH found in

our article concerning MORGELLONS SYNDROME.

That said, here are some things to consider about itching after messing with fiberglass insulation:

Dragging fiberglass refuse through a building causes dust contamination

Dragging fiberglass through a building is likely to have left a fair amount of broken fiberglass fragments on floors and through air transport, as settled dust on surfaces

. If you haven't done so you may want to clean the rooms through which insulation was dragged using damp wiping and then HEPA vacuuming of all surfaces, especially floors, carpets and any nearby furniture, shelving, etc.

Continued skin irritation after handling fiberglass insulation

It can take two or in a few cases even three trips through the washing machine to remove enough fine insulation fragments from clothing that it would not any longer be irritating to your skin

In my experience, working with insulation, especially during demolition when lots of material is broken up and airborne, the skin itching can last for a day or two after the work has been completed.

Taking a couple of showers, washing fully, may remove the dust, debris, and fiber fragments, or nearly all of them, from your person, but the skin may have become irritated, taking a bit longer to recover.

Check with your doctor if skin irritation continues past 1-3 days.

If itching continues after you've cleaned yourself, clothing, and any dust left in the building (use a HEPA vacuum when vacuuming up fine dust), then I suggest checking with your doctor or a dermatologist.

Consider dust sampling if you are not sure the building cleaning was adequate

If you have reason to suspect that there remains irritating dust and an irritating dust source in the building, I'd consider collecting one or two tape samples of settled dust from a horizontal surface in an area where you spend the most time and in an area where you think the dust is worst.

Have those samples analyzed to identify the dominant particles - as that may be diagnostic. Cost per sample for such analysis, using microscopy, should be in the $50. ballpark per sample. You shouldn't need many samples, perhaps two or at most two plus a control.

A settled dust collection procedure for collecting a dust sample that should be just fine is found at MOLD TEST KITS for DIY MOLD TESTS. Please do not send us your sample. I want to avoid even the appearance of any conflict of interest.

More about fiberglass exposure and itching and cleaning fiberglass-contaminated clothing are below in FAQs about fiberglass dust, particle, & mold hazards in buildings

Reader Question: Fiberglass (or Kevlar) fiber exposure dangers from boat building

2016/02/14 Char said:

When you say that there is always detectable amounts of fiberglass in air/dust, is it in noticeable amounts or microscopic or...? Should I be concerned about exposed insulation in my basement? And, when they're talking about special-purpose fiberglass being a carcinogen, what makes it "special purpose" and what products fall into that?

Would fiberglass from building boats/canoes be in that category? Thanks in advance, I'm having some fiberglass contamination issues and trying to learn what I can.

This question was posted originally at ENVIRO-SCARE - PUBLIC FEAR CYCLES where we discuss worries about fiberglass exposure.

Reply: OSHA & Other Regulations & Guidance about Fiberglass, Synthetic & Mineral Fiber Exposure


Having examined many indoor dust and air samples, I intended to say that I will almost always find at least some fiberglass fragments in most buildings. However the number of such particles will not normally be significant - certainly it's not the dominant particle.

Fiberglass release from building boats/canoes would be more noticeable as the fiberglass is cut, handled or abraded such as by sanding. In such an environment it might be significant, depending on what work is being done and how dust control is being managed.

I'd be more concerned about very small fiberglass fragments in the 1u range that may be released by grinding or sanding.

Char said:

So how concerned should I be... Building canoes we cut fiberglass matting and I wear a respirator, but I always get a significant amount on my clothing/jacket and it gets tracked into my vehicle and home. There is enough in my vehicle that I can easily see dozens of fibers, hundreds, when I shine a light.

My work has no dust collection system, only gloves, apron, and respirators. We also cut Kevlar, but I'm only really concerned with the fiberglass.

Reply: OSHA regulations & guidance on exposure to synthetic & mineral fibers


I cannot assess nor even guess at actual airborne particle level exposures from an e-text. Certainly there are OSHA regulations about dust control in the workplace.

ACGIH Recommended Airborne Exposure Limits to Fiberglass

The recommended airborne exposure limit is 1 fiber/cubic centimeter (for respirable fibers greater than 5 micrometers in length) averaged over an 8-hour workshift. 

NIOSH Recommended Airborne Exposure Limits to Fiberglass

The recommended airborne exposure limit is 3 fibers/m3 (for fibers less than or equal to 3.5 micrometers in diameter and greater than 10 micrometers in length) and 5 mg/m3 (for total particulates) averaged over a 10-hour workshift.

OSHA Fiberglass PEL

The legal airborne permissible exposure limit (PEL) is 5 mg/m3 (for the respirable fraction) and 15 mg/m3 (as total particulate) averaged over an 8-hour workshift.

Really? OPINION: Notice that there are no exposure standards for ultra-small fiberglass fragments, possibly because the exposure guideline writers focused on intact, un-damaged fiberglass substances in normal use and exposure.

Fiberglass Information: Quoting from OSHA,

Synthetic mineral fibers are fibrous inorganic substances made primarily from rock, clay, slag, or glass. These fibers are classified into three general groups: fiberglass (glass wool and glass filament), mineral wool (rock wool and slag wool), and refractory ceramic fibers (RCF).

There are more than 225,000 workers in the US exposed to synthetic mineral fibers in manufacturing and end-use applications.

How do I find out about employer responsibilities and workers' rights?

Workers have a right to a safe workplace. The law requires employers to provide their employees with safe and healthful workplaces. The OSHA law also prohibits employers from retaliating against employees for exercising their rights under the law (including the right to raise a health and safety concern or report an injury). For more information see or Workers' rights under the OSH Act.

OSHA can help answer questions or concerns from employers and workers. To reach your regional or area OSHA office, go to the OSHA Offices by State webpage or call 1-800-321-OSHA (6742).

Small businesses may contact OSHA's free On-site Consultation services funded by OSHA to help determine whether there are hazards at their worksites. To contact free consultation services, go to OSHA's On-site Consultation webpage or call 1-800-321-OSHA (6742) and press number 4.

Workers may file a complaint to have OSHA inspect their workplace if they believe that their employer is not following OSHA standards or that there are serious hazards. Workers can file a complaint with OSHA by calling 1-800-321-OSHA (6742), online via eComplaint Form, or by printing the complaint form and mailing or faxing it to the local OSHA area office. Complaints that are signed by a worker are more likely to result in an inspection.

If you think your job is unsafe or if you have questions, contact OSHA at 1-800-321-OSHA (6742). Your contact will be kept confidential. We can help. For other valuable worker protection information, such as Workers' Rights, Employer Responsibilities, and other services OSHA offers, visit OSHA's Workers' page. - retrieved 2016/02/16, original source:

Fiberglass & Mineral or Synethtic Fiber Exposure Hazards, Standards & Regulations

And see the article above where I explain that most likely the more serious hazards are with the smaller particles. An individual can also protect himself with respirator and proper clothing. At home I'd HEPA vacuum areas where you are concerned about high dust levels and I'd clean clothes by laundering.

Char said:
Thank you for your reply. However, I am Canadian so those phone numbers and contact information doesn't apply to me. Is there something similar for Canadians? I'm assuming there would be

Canadian & Other Fiberglass Hazard Resources - Yacht-Makers Lung research

Sorry for the presumption. The US OSHA general advice about fiberglass hazards should be valid world-wide but of course none of the phone numbers make sense for you.

In Canada see Canada's National Workplace Health & Safety Website
There you'll see a provincial map that gives contact information by province.

Canadians are less fearful of fiberglass than some Yanks. The Health Canada discussion of workplace IAQ mentions mold and general hazards and housekeeping

CCOHS FAQs on IAQ includes this comment on Canadian laws or guidelines for IAQ - not specific to fiberglass

Many Canadian jurisdictions do not have specific legislation that deals with indoor air quality issues. In the absence of such legislation, the "general duty clause" applies. This clause, common to all Canadian occupational health and safety legislation, states that an employer must provide a safe and healthy workplace. Thus, making sure the air is of good quality is the employer's duty.

Several organizations* have published recommended guidelines for indoor air quality. For example, Health Canada has prepared a number of publications on air quality. In the United States, the Occupational Safety and Health Administration (OSHA) has compiled information on Indoor Air Quality.

In addition, IAQ is implied in most building codes as design and operation criteria. Building codes in Canada and the U.S. generally refer to the American Society of Heating, Refrigerating, and Air Conditioning Engineers* (ASHRAE) Standard 62.1-2010 - Ventilation for Acceptable Indoor Air Quality (or previous versions), or other acceptable standards.

It is important to understand that most IAQ standards and guidelines are established to ensure the comfort of workers. So these values tend to be lower than regulatory values that are set to protect workers from possible health based hazards.

*We have mentioned these organizations as a means of providing a potentially useful referral. You should contact these organizations directly for more information. - "OSH Answers Fact Sheets, Indoor Air Quality - General, Are there laws or guidelines for IAQ [in Canada]?", retrieved 2016/02/16, original source:

Fiberglass hazards in boatbuilding

An industry where fiberglass hazards have long been discussed as "Yachtmaker's Lung Disease"

You'll see that styrene exposure hazards are also discussed.

For U.K. readers more about dust and fiberglass hazards and regulations are at POST a QUESTION or READ FAQs in this article - click to show the FAQs.


Continue reading at FIBERGLASS DETECTION in BUILDING AIR & DUST or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see FIBERGLASS HAZARD FAQs - questions & answers posted originally at this page



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Fiberglass Hazard Articles

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