From your link:
SECTION 11. TOXICOLOGICAL INFORMATION
IARC No component of this product present at levels greater than or equal to 0.1% is identified as probable, possible or confirmed human carcinogen by IARC.
ACGIH No component of this product present at levels greater than or equal to 0.1% is identified as a carcinogen or potential carcinogen by ACGIH.
OSHA No component of this product present at levels greater than or equal to 0.1% is identified as a carcinogen or potential carcinogen by OSHA
> warning for formaldehyde.Trace amounts can possibly sweat out in specific conditions .. which is why you might choose to install with a vapor barrier.
Those limits are:
So the Prop 65 warning certainly seems reasonable from here.https://downloads.regulations.gov/EPA-HQ-OPPT-2023-0613-0230...