The full disclosure of chemicals used in fracturing fluids has been urged for for years by scientists, politicians, and the public. At the same time, manufacturers of fracturing fluids claim trade secrets to protect some of their chemicals from being disclosed, to competitors and to the public. This results in that the information given on a fluid used in a specific well is possibly incomplete when reported on disclosure websites like FracFocus (USA, Canada) or NGS Facts (Europe), which are voluntary, industry-backed fracking chemical disclosure registries. 

However, there is progress: in May 2014, a US Department of Energy task force report recommended a new approach to chemical disclosure on the website FracFocus:

"A large fraction of reporting wells claim at least one trade secret exemption. The Task Force favors full disclosure of all known constituents added to fracturing fluid with few, if any exceptions. A “systems approach” that reports the chemicals added separately from the additive names and product names that contain them, generally should provide adequate protection of trade secrets. The Task Force further calls for state and federal regulators to adopt standards for making a trade secret claim and establish an accompanying compliance process and a challenge mechanism."

Read the article "Uneven State Rules And Trade Secrets Fuel Fracking Debate" (C&EN, March 2015, web link) about the current discussion on disclosure and related lawmaking in the USA.