HMBP Exemptions and Reporting Thresholds

Some hazardous materials have different reporting thresholds than the standard 55 gallons, 200 cubic feet, and 500 pounds. The thresholds at which these materials become reportable, and thus must be included on an HMBP, are listed below.

Mixtures consisting of less than 1% of a hazardous material​ or 0.1% for carcinogens

All amounts exempt

Compressed air used for emergency response and safety​

​All amounts exempt

​Extremely hazardous substances, as defined by the Code of Federal Regulations, Title 40, §355.61

Threshold planning quantity (Appendix A, Appendix B of Part 355) or 500 pounds, whichever is less

Simple asphyxiants (nitrogen, helium, argon, neon, krypton, xenon) and mixtures of these gases containing 21% or less of oxygen

​1,000 cubic feet

​Carbon dioxide , including when mixed with simple asphyxiants (nitrogen, helium, argon, neon, krypton, xenon)

​1,000 cubic feet

​Oxygen, nitrogen, and nitrous oxide used at a health service facility (medical, veterinary, etc.)

​1,000 cubic feet

​Nonflammable refrigerant gases used in a refrigeration system

​1,000 cubic feet

​Gases in closed fire suppression systems

​1,000 cubic feet

​Refrigerants in a closed cooling system (not including ammonia or flammable gases) that is used for comfort cooling or to cool computer rooms

​All amounts exempt

Fluid in a hydraulic system

All amounts exempt, if aggregate storage of oil at the facility is less than 1,320 gal

​Irritants and sensitizers

​550 gal if liquid, or 5,000 lbs if solid

Lubricating oil

​>55 gal of each type or >275 gal aggregate

​Oil-filled electrical equipment not contiguous to an electric facility

​All amounts exempt, if aggregate storage of oil at the facility is less than 1,320 gal

​Recyclable paint

​10,000 lbs solid or 1,000 gal liquid

​Propane used for cooking, heating employee work areas, or heating water at a business

​>500 gal

Radioactive materials

​Reportable if handled in quantities requiring an Emergency Plan per Schedule C of Part 30, Part 40, or Part 70 of 10 CFR Chapter 1

Combustible metal or metal alloy defined as a combustible dust, flammable solid, or magnesium

100 pounds

Consumer Products in a retail establishment that have a NFPA/HMIS rating of 1 or 2 Exempt
Consumer Products in a retail establishment that have a NFPA/HMIS rating of 3 or 4

165 gals. for liquids, 1500 lbs. for solids, and 600 cu ft. for gases

Hazardous materials liquids or gases on a vehicle that are used solely for that vehicle’s motive power (ex. Gasoline, diesel, propane)


Treated Wood Waste Exempt unless meeting Title 42, Section 11022 (Tier I) requirement to disclose.

*All amounts listed in cubic feet are measured at standard temperature and pressure (STP). 

Farms are conditionally exempt from having to submit the emergency response plan section of an HMBP as long as they meet the following requirements:

  • Each building which stores hazardous materials has signs posted providing notice of storage of pesticides, petroleum fuels and oil, and types of fertilizers.
  • Provide training for employees per California Health and Safety Code (HSC) §​25505(a)(4).

Additionally, the following materials are exempt from HMBP reporting thresholds if they are stored at an unstaffed remote facility (at least 1/2 mile from the nearest occupied structure):

​Compressed inert gases

>​​1,000 cubic feet

​Combustible liquids used as a fuel source

>​500 gal

EHS corrosive liquids used as electrolytes

>​500 lbs

​Lubricating and hydraulic fluids

​>500 gal

​Hydrocarbon gas used as a fuel source

​>1,200 gal

​Mineral oil within electrical equipment

>​1,320 gal​

*Remote facilities, as defined above, may still be subject to the reporting requirements of our Hazardous Materials Storage Ordinance

The following materials are not exempt, but are listed here for clarification purposes:

​Lead acid batteries

​Report in gallons based on quantities of electrolyte alone

​Universal waste

​Report in aggregate by hazard type

​Perchlorate material (per HSC §25210.5)

​55 gallons, 200 cubic feet, 500 pounds

©2024 County of Santa Clara. All rights reserved.