This website is a U.S. engineering testing organization that test products to ensure certain types of products meet quality and safety standards.

http://www.ul.com/media/newsrel/nr090204.html Underwriter's Laboratories Inc. is known for years in the U.S. as one of the American national certification agencies for certain building materials, building systems and some consumer products. Other U.S. agencies handle testing and quality certificatioh of products. ULI writes national engineering standards that involve committees of engineeringe experts.

Canada has Underwriters' Laboratories of Canada. But in Canada the air-fresheners might be covered by another national Canadian engineering and testing organization (ie. CSA but doesn't look like it) or the federal govn't.

From your ex-fire protection and engineering librarian.

Yes, I saw the hoax, urban legends internet websites when I did superficial searching.... YOu need to know the agencies that test in a scientific manner and preferably to a standard that covers physical properties of materials.