Appendix A: Chemicals of Interest (COI)

Stock image of chemicals in tubes and beakers.Keeping hazardous chemicals out of the hands of those who would misuse them is a responsibility the Department shares with facility owners and operators, employees, and emergency responders.

Appendix A of the CFATS regulation (6 CFR Part 27) lists more than 300 chemicals of interest (COI), and their respective screening threshold quantities (STQ), which are categorized under three main security issues:

  • Release: Toxic, flammable, or explosive chemicals or materials that can be released at a facility.
  • Theft or Diversion: Chemicals or materials that, if stolen or diverted, can be converted into weapons using simple chemistry, equipment, or techniques.
  • Sabotage: Chemicals or materials that can be mixed with readily available materials.

First Step: Read the Appendix A CFATS Chemicals of Interest (COI) List if your facility possesses or plans to possess any chemical(s). Any COI that meets or exceeds the STQ must be reported to DHS.

Facilities that Possess COI

A facility that meets or exceeds the specified concentrations and quantities for any COI is required to report possession of those chemicals to DHS by completing an online survey called a Top-Screen via the Chemical Security Assessment Tool.

The Department’s Infrastructure Security Compliance Division (ISCD) reviews Top-Screens using a risk-based methodology. Facilities are notified if they are:

  • Determined to be a high-risk facility, and ranked into Tiers 1,2, 3, and 4, with Tier 1 being the highest risk.
  • Determined to not be a high-risk facility and not regulated under CFATS.

Facilities determined to be “high-risk” are required to develop a security plan and implement security measures that reduce the risks associated with their COI.

COI Resources for Facilities

ISCD regularly engages with stakeholders to identify how to reach new segments of the population and ensure that those who hold COI are aware of their obligation to report.

Please download, print, and distribute these voluntary resources to increase the awareness of the CFATS program.

CFATS Nitromethane Flyer — This flyer helps facilities become aware that Nitromethane is a COI under CFATS, and an Improvised Explosive Device (IED) precursor chemical. Any individual or facility that possesses 400 lbs. (approximately 42 gallons) or more of nitromethane must report their chemical holdings to DHS.

CFATS Propane Flyer — This flyer helps facilities become aware that Propane is a Release-Flammable chemical—meaning, if intentionally released, it has the potential to create a vapor cloud explosion that would affect populations within and beyond the facility. Any individual or facility that possesses 60,000 lbs. or more of propane must report their chemical holdings to DHS.

Receiving a COI Flyer — This flyer is a voluntary tool facilities can use when shipping, selling, or distributing a COI from their facility.

Top-Regulated COI Fact Sheet — This fact sheet lists the most commonly reported COI, the main security issues, and the risks they pose.

Appendix A Final Rule

On November 20, 2007, the Department published the Final Rule for the Appendix A in the Federal Register making all provisions of 6 CFR Part 27, including § 27.210(a)(1)(i), operative and in effect.

In developing Appendix A, the Department referenced existing expert sources of information including other federal regulations related to chemicals such as:

  • Chemicals covered under the Environmental Protection Agency’s Risk Management Program
  • Chemicals included in the Chemical Weapons Convention
  • Hazardous materials, such as gases that are poisonous by inhalation
  • Explosives regulated by the Department of Transportation

The Department continues to assess available information about chemicals critical to the government mission and the economy. The Department will use the information it collects through the Top-Screen process to identify facilities responsible for economically-critical and mission-critical chemicals.

Contact Information

For more information about the CFATS program, please contact

Last Published Date: August 14, 2018

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