Aboveground Petroleum Storage Act: Tank in an Underground Area (TIUGA)
Tanks in underground areas (TIUGA) are regulated under the California Aboveground Petroleum Storage Act (APSA).
The following information on TIUGAs is intended to assist Unified Program Agencies (UPA), the regulated community, and applicable authorities having jurisdiction (AHJ) in understanding provisions of TIUGAs per the California Health and Safety Code (HSC), Division 20, Chapter 6.67.
Disclaimer: The information contained herein as a whole or any specific element of the information contained herein does not replace or substitute for any statutory or regulatory provisions, nor is the information contained herein a regulation in itself. In the event of a conflict between the information contained herein and any statute or regulation, the information contained herein would not be controlling. Furthermore, nothing contained herein should be considered legal advice nor be considered a substitute for seeking legal guidance in regard to compliance for any statutory or regulatory provision. Thus, information contained herein does not impose legally binding requirements on the State, UPAs, or the regulated community, and might not apply to a particular situation based upon certain circumstances.
References cited herein are subject to change and information will be revised as necessary to reflect any relevant future statutory or regulatory amendments.
Under APSA, a TIUGA must meet all of the following:
- The storage tank is stationary.
- The storage tank is located on or above the surface of the floor in a structure at least 10 percent below the ground surface, including but not limited to, a basement, cellar, shaft, pit, or vault.
- The structure in which the storage tank is located must provide for secondary containment of the contents of the tank1, piping, and ancillary equipment, until cleanup occurs.
- The structure in which the storage tank is located must allow for direct viewing of the exterior of the tank except for the part of the tank in contact with the surface of the floor.2
- The storage tank meets one or more of the following categories:
- Lubricant/coolant tank - Contains petroleum (new or used oil) as lubricant or coolant in motor engines, transmissions, or oil-filled operational or manufacturing equipment (HSC Section 25270.2(o)(1)(C)(i)).
- Hazardous waste tank - Contains petroleum that is considered a hazardous waste and complies with the hazardous waste tank standards in the California Code of Regulations (CCR), Title 22, Division 4.5, Chapter 15, Article 10 (HSC Section 25270.2(o)(1)(C)(ii)).
- Emergency system tank - Contains petroleum to be used for emergency systems, solely in connection with a fire pump or an emergency system, legally required standby system, or optional standby system as defined in the California Electrical Code (HSC Section 25270.2(o)(1)(C)(iii)).
- Other tank - Does not fit into any of the above three categories and contains petroleum (HSC Section 25270.2(o)(1)(C)(iv)).
1 A shop-fabricated double-walled storage tank meets the requirement for secondary containment of the contents of the tank (HSC Section 25270.2(o)(1)(B)).
2 Direct viewing of the exterior of the tank is not required if inspections of the interstitial space are performed or if the storage tank has a mechanical or electronic device that will detect leaks in the interstitial space or containment structure and alert the tank operator (HSC Section 25270.2(o)(2)).
Under APSA, direct viewing in regard to a storage tank means direct visual inspection of all exterior surfaces of the tank (except for the part of the tank in contact with the surface of the floor) and the entire length of all piping and ancillary equipment (where applicable) by a person or through the use of visual aids, including, but not limited to, mirrors, cameras, or video equipment (HSC Section 25270.2(p)).
Note: The amount of space between the exterior of a tank and the wall or other surface is not specified in APSA. However, contact the AHJ for fire code requirements on separation distances. The intent of the direct viewing requirement is to have the ability to check for visible signs that the tank is leaking, e.g. staining on the wall, liquid on floor near tank, etc.
Yes, if the tank facility has a TIUGA (HSC Section 25270.3(c)). Only the TIUGAs are subject to APSA if a tank facility has less than 1,320 gallons of total aboveground petroleum storage capacity. However, the following TIUGAs are excluded from the requirements of APSA if a tank facility has less than 1,320 gallons of total aboveground petroleum storage capacity (including TIUGAs):
- The tank holds hydraulic fluid for a closed loop mechanical system that uses compressed air or hydraulic fluid to operate lifts, elevators, or other similar devices.
- The tank is a heating oil tank.
- The tank is a sump, separator, clarifier, catch basin, or storm drain.
If a tank facility has a total aboveground petroleum storage capacity of 1,320 gallons or more (including TIUGAs), then a TIUGA storing hydraulic fluid for a closed loop mechanical system that uses compressed air or hydraulic fluid to operate lifts, elevators, or other similar devices is subject to the requirements of APSA.
A petroleum storage tank located substantially beneath the surface of the ground that does not meet the definition of a TIUGA as described in APSA is an underground storage tank (UST) system. UST systems are required to comply with the requirements of the HSC Division 20, Chapter 6.7 and 23 CCR Division 3, Chapter 16.
If an existing storage tank meets the definition of a TIUGA, then it is subject to APSA.
If an existing storage tank containing hazardous substances does not meet the definition of a TIUGA, then it may be considered a UST system subject to the provisions of HSC Chapter 6.7 and 23 CCR.
For a tank facility with one or more TIUGAs, the owner or operator is required to do the following:
- Prepare and implement a Spill Prevention, Control, and Countermeasure (SPCC) Plan OR amend an existing SPCC Plan and implement the amended SPCC Plan,
- Conduct periodic inspections of each TIUGA (per the tank facility’s SPCC Plan),
- Comply with current Federal SPCC regulations found in 40 CFR 112,
- Mark the APSA question on the Business Activities section as “Yes” and make a submittal into the statewide information management system, also known as the California Environmental Reporting System (CERS),
- File or submit an annual tank facility statement or Hazardous Materials Business Plan (HMBP) into CERS,
- Complete additional APSA data fields in CERS, as applicable, and
- Pay the applicable fee(s) to the UPA, including the Unified Program state surcharge for the APSA program.
A tank facility with one or more TIUGAs in the “Other” category (refer to Question 1 for TIUGA categories) must also comply with the applicable 24 CCR Part 9 piping requirements referred to in APSA and included in the fire code.
Contact your UPA for additional requirements and for assistance to ensure your tank system complies with all applicable APSA requirements.
Under APSA, with the exception to an emergency vent line that is solely designed to relieve excessive internal pressure, all piping connected to TIUGAs in the “Other” category (refer to Question 1 for TIUGA categories), including any portion of a vent line, vapor recovery line, or fill pipe that is beneath the surface of the ground, and all ancillary equipment that is designed and constructed to contain petroleum, must either be visually inspected by direct viewing or has both secondary containment and leak detection that meet the requirements of the regulations adopted by CAL FIRE-Office of the State Fire Marshal.
Effective July 1, 2018, the following fire code requirements for TIUGAs and their associated piping systems are found in 24 CCR Part 9 (California Fire Code [CFC]).1
- All TIUGAs and associated piping systems shall be provided with spill control and secondary containment that are designed and constructed as outlined in Section 5004.2, except as modified by Section 5703.6.2.2. [CFC Section 5703.4.1 (2016 and 2019 editions)]
- Below-grade or underground piping systems connected to TIUGAs in the “Other” category shall have secondary containment. The building, room, or area where the tank and piping are located may be used as secondary containment if it meets the containment and drainage methods described in Section 5004.2.2.1. [CFC Section 5703.6.2.2 (2016 and 2019 editions)]
- All portions of below-grade and underground piping systems connected to TIUGAs in the “Other” category shall be monitored for leaks by one of the following methods: [CFC Section 5703.6.2.2 (2016 and 2019 editions)]
- A listed or approved leak detection system that either activates an audible and visual alarm or stops the flow of product when a leak is detected.
- Direct visual inspection conducted monthly by designated personnel.
- Indirect visual inspection conducted monthly through the use of, but not limited to mirrors, cameras or video equipment.
- If the above methods cannot be met, an alternative means shall be provided in accordance with Section 18.104.22.168.
All tank systems will be required to meet additional applicable fire code requirements. Contact the AHJ, typically a fire code official, for additional and/or more stringent fire code requirements.
1 To view the current fire code online, visit the International Code Council public access website. Click on the current edition and then click on Part 9 of 24 CCR.
No. The fire code requirements for piping systems connected to TIUGAs that became effective July 1, 2018, are not retroactive. The requirements are only for systems installed or constructed on or after July 1, 2018.
An owner or operator of a TIUGA, including connected piping systems, installed or constructed before July 1, 2018, must follow the applicable piping requirements for UST systems found in HSC Chapter 6.7 and 23 CCR. Alternatively, the owner or operator may choose to modify or upgrade the tank system so it meets the current definition of a TIUGA.
If the day tank meets the definition of a TIUGA per HSC Section 25270.2(o), then the day tank is subject to APSA.
No. A tank must be located in a structure that is at least 10 percent below the ground surface and be situated on or above the surface of the floor to meet the definition of a TIUGA. While a partially buried tank cannot be considered a TIUGA, a partially buried tank with less than 10 percent below the ground surface can be an aboveground storage tank subject to APSA.
Below are three examples of tank configurations and a determination of requirements the tanks are subject to:
- If the tank is located in a structure that is at least 10 percent below the ground surface and any portion of the exterior of the tank, other than the part in contact with the floor of the structure, cannot be directly viewed, then the tank system is a UST system and is subject to UST requirements.
- If the tank is located in a structure that is less than 10 percent below the ground surface and at least 10 percent of the entire tank system’s volume, including piping, is below the ground surface or enclosed in earthen materials, then the tank system is a UST system and is subject to UST requirements.
- If the tank is located in a structure that is less than 10 percent below the ground surface and less than 10 percent of the entire system’s volume, including the piping, is below the ground surface or enclosed in earthen materials, then the tank system is an aboveground storage tank and may be subject to APSA.
No. However, if a portable container/tank in an underground area is managed as a stationary or fixed container/tank, then the container/tank may be subject to the requirements of APSA, including requirements of TIUGAs.
Yes. Under APSA, a TIUGA with a capacity to store less than 55 gallons of petroleum is required to have secondary containment, be inspected monthly, and the owner or operator maintains a log of inspection records for review by the UPA upon request. This tiny TIUGA is excluded under the APSA definition of an aboveground storage tank.
Note: An owner or operator of a tank facility with this tiny TIUGA is excluded from the APSA requirement to pay fees, file or submit an annual tank facility statement or HMBP into CERS, or prepare and implement an SPCC Plan. The tiny TIUGA also does not count toward: (1) a tank facility’s total aggregate aboveground petroleum storage capacity nor (2) the total number of TIUGAs in the APSA Facility Information submittal element in CERS.
Information on underground storage tanks (UST) connected to TIUGAs may be found on page 5 of the July 2020 edition of the Unified Program Newsletter