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Frequently Asked Questions

Why did you call this website Transparency?
The website is called Transparency because it comes out of a hope for a future where people know what our buildings are made out of – a transparent world.
What kind of marketplace change are you hoping to see?
We hope that building product marketplace becomes transparent from extraction to end of life for all points of contact from manufactures through to de-constructors so that people can make informed decisions about specifying, maintaining and disposal of the products in their buildings.
What is the Precautionary Principle?
The precautionary principle is based on the idea that, in the absence of scientific consensus, if an action has a suspected risk of causing harm to humans or to the environment, that the action is harmful. The burden of proof that it is not harmful falls on those taking the action.
How are the Asthma and Flame Retardant lists different from the Precautionary List?
All these lists are intended to empower people to make informed decisions and represents information that we believe dictates appropriate caution when making design decisions. The Asthma Triggers + Asthmagens List is a compilation of suspected asthmagen and asthma triggers, sourced from government and third party lists. For asthma the intent of our list is to raise awareness on the pervasiveness of substances with suspected links to asthma in the built environment and the need for research on this topic.
Are these “red” lists?
No, these lists are intended to empower people to make informed decisions and represent information that we believe dictates appropriate caution when making design decisions.
Are these lists original research?
No, these lists are compilations of information and references that are publically available with the exception of the Flame Retardants list which is original research by the Green Research Policy Institute.
What happened to the old site?
This re-branded website contains the same information as the old site, but has been updated and expanded.
Who is this information intended for?
The information on this website is intended for specifiers and building owners, but everybody in the design and construction industry should find useful information.
Why did I have to agree to a Terms of Use?
It ensures that you understand the intent and basis of this website.
I want to design with sustainable and healthy materials in mind, but I don't have a degree in chemistry – How am I supposed to use the precautionary list?
A deep knowledge of chemistry is not required. The information on this website is presented in a way that is meant to be understandable for interior designers, architects, our clients, and the larger building community.
My firm has a materials librarian who monitors what goes into the library – why do I need to understand this information?
There are millions of building products and each one is made up of different substances. In addition, the composition of building products is not constant - manufacturers, and their supply vendors, regularly change the formulation of their products. Lastly, it is not common practice for manufacturers to reveal the substances in their products. For all these reasons, the lists and other materials on this website should be used to as starting points for conducting research on building products with the goal of making informed decisions.
What if I can't find an appropriate alternative substance?
Some of the substances currently do not have alternatives. When this is the case we recommend, where possible, to limit the use of the substance on a project.

Note: The Flame Retardant List is independent research on flame retardants commonly found in building products and furnishings. Please note that for flame retardants there are not often alternatives to the substances listed.
I have a product I want to know more about…now what?
The lists on this website are not about individual building products, but rather about substances commonly found in those products. If you wish to learn about what substances make up the composition of a particular building product, we recommend you contact the manufacturer directly. The Pharos Project is another resource ( that provides some additional information on building product composition.
How can I introduce the Precautionary List to my company / firm, so that we can reference it during future projects?
We have posted this openly on our website with the hope that this list will be used by everybody who is interested in human and environmental health. We recommend that you download the presentation labeled “An Introduction to Healthy Materials” from our media section.
How do I reference these lists in my paper, article, or project?
Please refer to this list as
Perkins+Will's Precautionary List at
Perkins+Will's Asthma List at
Perkins+Will's Flame Retardant List at