California Air Resources Board

This page contains "frequently asked questions" and responses prepared by CARB staff as means to convey further information pertaining to the development of performance standards that will apply to continuously operating emission detection systems within the leak detection and response plans required under SB-1137.

-This webpage was updated on July 21, 2025-

Section 1: Senate Bill 1137

1.1.  What is Senate Bill 1137?

California Senate Bill 1137 (SB 1137, Gonzalez, 2022) sets requirements for protecting public health by creating a minimum health and safety distance of 3,200 feet between sensitive receptors and an oil and gas production well or facility. Oil and gas facility operators within this distance from a sensitive receptor are required to implement strict pollution controls, including developing leak detection response plans to protect human health.

1-2.  Why was implementation of SB 1137 delayed?

SB 1137 was signed into law by Governor Newsom in September 2022, but implementation was put on hold due to a referendum that qualified for the November 2024 California election ballot. On June 28, 2024, the referendum was withdrawn, and the law went into immediate effect. Because the original implementation deadlines were no longer workable, the Legislature drafted Assembly Bill 218, a trailer bill, which was signed into law by Governor Newsom on September 30, 2024. AB 218 provides funding to implement SB 1137 and establishes revised implementation deadlines for leak detection response plan submission and other SB 1137 requirements.

Section 2: Applicability

2-1.  Who does SB 1137 apply to?

The requirements of SB 1137 apply to operators of existing oil and natural gas wells and production facilities that are within health protection zones. “Operator” means a person who, by virtue of ownership, or under the authority of a lease or any other agreement, has the right to drill, operate, maintain, or control a well or production facility (Public Resources Code section 3009).

2-2.  What are health protection zones?

SB 1137 establishes health protection zones (HPZ) around sensitive receptors located within 3,200 feet of oil and gas production wells and production facilities. SB 1137 bans the development of new oil and gas wells in the HPZ except under limited circumstances. Operators with an existing production facility or well with a wellhead within an HPZ are required to develop and submit a leak detection and response plan to the Geologic Energy Management Division in the California Department of Conservation (CalGEM).

2-3.  What is a sensitive receptor?

Sensitive receptors include residences, schools, community resource centers, childcare facilities, parks, playgrounds, health care facilities, hospitals, nursing homes, live-in housing, and any building housing a business open to the public.

2-4. Are there any exemptions under SB 1137?

SB 1137 exempts underground gas storage wells and their associated production facilities since those facilities already have continuous monitoring requirements. SB 1137 also limits its applicability to oil and gas production facilities and states that development of oil and gas fields into nonfossil fuel production and injection, and other uses is not subject to the requirements of SB 1137.

Section 3: Leak Detection and Response Plans

3-1. Who must submit a leak detection and response plan?

Operators with an existing production facility or well with a wellhead within a health protection zone are required to develop and submit a leak detection and response plan to CalGEM.

3-2.  What is required in a leak detection and response plan?

SB 1137 requires leak detection and response plans to include five key components:

• A continuously operating emission detection system;

• Identification of the chemical constituents, such as methane and hydrogen sulfide, as well as potential toxics of highest concern in the region as identified by CARB or local air districts, that will be detection targets for the emission detection system;

• An alarm system that effectively, immediately, and reliably alerts the operator of leaks;

• An alarm response protocol to rapidly identify and repair leaks, and

• Provisions to notify local communities when a leak source is not identified or repaired within 48 hours and to determine the chemical composition of such leaks.

3-3.  What are the deadlines for leak detection and response plans?

• By July 1, 2028, all operators of existing oil and gas production facilities or wells within the health protective zone must develop and submit a leak detection and response plan to CalGEM.

• By July 1, 2029, CalGEM, with CARB’s concurrence, must either approve the leak detection and response plans or provide notice of deficiency.

• By July 1, 2030, operators must fully implement an approved leak detection and response plan or suspend all production and injection operations within the health protective zone.

Section 4: Emission Detection Systems

4-1.  What is an emission detection system?

SB 1137 requires leak detection and response plans to include a continuously operating emission detection system designed to provide for rapid detection of target chemical constituents to identify leaks before emissions impact the surrounding communities. SB 1137 requires the emissions detection system to include:

• An alarm system that effectively, immediately, and reliably alerts the operator when triggered; and

• A meteorological system that is appropriately sited with the ability to continuously record measurements.

CARB staff is developing a regulatory proposal to specify performance standards for the emission detection systems required by SB 1137. For more information about the rulemaking process, past and upcoming meetings, and opportunities to provide input, please refer to CARB’s Senate Bill 1137 Implementation  webpage.

4-2.  What air pollutants are emission detection systems required to target?

SB 1137 requires leak detection and response plans to identify the chemical constituents, such as methane and hydrogen sulfide, as well as potential toxics of highest concern in the region as identified by the State Air Resources Board or local air district that will be detection targets for the emissions detection system to ensure early detection and prompt repair of leaks that otherwise may result in emissions impacting the surrounding communities. Not all chemical species that may be found in the oilfield are required to be detection targets and methane may serve as a surrogate for chemical constituents that cannot be continuously monitored but are identified in the leak detection and response plan.

CARB staff is currently consulting with air districts to identify potential toxics of highest concern in each region of California. CARB staff also is developing a regulatory proposal to specify the method operators will use to identify site-specific detection targets. For more information about the rulemaking process, past and upcoming meetings, and opportunities to provide input, please refer to CARB’s Senate Bill 1137 Implementation webpage.

4-3.  What could a system look like? What are the basic components of an emission detection system?

Most continuously operating emission detection systems (those that are stationary, also known as fixed ground mounted systems) use one or more sensors that are responsive to the presence of one or more hydrocarbon species.  While some sensors are methane specific, others respond to a wider range of hydrocarbons. Many systems include meteorological sensors for wind speed, wind direction, temperature and humidity. The meteorological systems may be integrated with the sensor or may be deployed separately. Most systems rely on wind transport of emissions from the source to the sensor or the part of the atmosphere that is sampled. Most systems are coupled with communications and data analytics that are designed to interpret the sensor data to create actionable information such as emission concentration, emission quantification, and emission localization. Outputs may be delivered through online dashboards, alarms, or other visual prompts. 

4-4.  When will alarms be triggered?

Conceptually, alarms will be triggered when predetermined levels of detection targets for the emission detection system are exceeded. Oil and gas production wells and facilities throughout California vary in production capacity and processing complexity with site-specific equipment configurations, site-specific proximity to sensitive receptors, and site-specific composition of gaseous emissions. Due to the variation in facility operating parameters, at present time, CARB staff does not anticipate that a one size fits all alarm threshold approach will be applied.  At present time, CARB staff is in the preliminary stages of developing a draft regulatory proposal to specify the method operators will use to determine those levels.  CARB staff will release draft regulatory text along with draft supporting information on the SB1137 Implementation program webpage in late 2025 and will host a series of public workshops shortly after to solicit feedback.

Section 5: Alarm Response Protocol

5-1. What is an alarm response protocol?

SB 1137 requires leak detection and response plans to include an alarm response protocol that provides for immediate action to rapidly identify and fix a leak that is the source of the emissions detected by the emissions detection system. The alarm response protocol is required to include a communication plan for notification of local emergency responders and public health authorities, CalGEM, and the people in the affected community. The alarm response protocol shall provide for:

• Compliance with all local, state, and federal requirements for reporting leaks of hazardous emissions; and

• Collection and determination of the chemical composition of a representative sample near the leak when a continuous alarm event indicates that emissions from the leak may have impacted the surrounding community; and

• Suspension of use of a well or production facility if the source of the emissions is a leak from that well or production facility, until the leak has been corrected and CalGEM has approved the resumption of its use.

5-2.  What happens if the cause of an emissions detection system alarm is not quickly fixed?

In the event that the source of the emissions is not identified and the leak stopped within 48 hours of the leak being identified, SB 1137 requires the notification of local emergency responders and public health authorities, CalGEM, and the people in the community, including notification in languages that are easily understood by the affected community.

Section 6: Agency Roles and Responsibilities

6-1.  What are CARB responsibilities under SB 1137?

Under SB 1137, CARB’s responsibilities include:

• Adopting regulations as necessary to implement and set performance standards for emission detection systems and leak emission composition determination methods.

• Working with CalGEM, to review the leak detection and response plans and either approve the plans or provide notice of deficiency.

• Working with CalGEM to develop methods for providing public access to the data generated by operators from emission detection systems.

6-2.  What is CalGEM’s role under SB 1137?

Under existing law, prior to SB 1137, CalGEM, under the direction of the State Oil and Gas Supervisor, is required to supervise the drilling, operation, maintenance, and abandonment of oil and gas wells in California and the operation, maintenance, and removal or abandonment of tanks and facilities related to oil and gas production within an oil and gas field, so as to prevent damage to life, health, property, and natural resources. Under existing law, operators of wells are required to file a written notice of intention to commence drilling, and any drilling was prohibited until approval was granted by the Supervisor or District Deputy.

SB 1137 prohibits CalGEM from approving any notice of intention within a health protection zone, with a few exceptions. Oil and gas operators who submit a notice of intention, except under certain instances, must submit either: 1) a sensitive receptor inventory and map of the area within 3,200 feet radius of the wellhead/proposed wellhead, or 2) a statement certifying that the operator has confirmed that there are no sensitive receptors within the 3,200-foot radius of the wellhead.

Additionally, SB 1137 requires a multiagency effort for all oil and gas production facilities or wells with a wellhead within a health protection zone to comply with specified health, safety, and environmental requirements. These health, safety, and environmental requirements would, among other things, require compliance with requirements set by CARB, local air districts, CalGEM, the State Water Resources Control Board, and regional water quality control boards related to applicable permits, public notice, sound levels, light generation, migration of dust and particulates beyond property boundaries, emissions and vapor venting, and chemical analyses of produced waters. SB 1137 would also require all operators with a production facility or well with a wellhead in a health protection zone to submit a leak detection and response plan to CalGEM, as provided, to the division.

Section 7: Community Notification

7-1.  When does the community get notified of a leak?

SB 1137 requires people in the affected community to be notified of a leak in the event that the source of the emissions is not identified and the leak stopped within 48 hours of the leak being identified.

7-2.  Will communities be able to review leak detection and response plans before their approval? Will communities have access to emission data?

SB 1137 does not grant CARB authority to allow community review and comment of the leak detection and response plans prior to their approval. SB 1137 does require community access to data from the emissions detection systems. CARB and CalGEM are still evaluating different options for how to provide public access to the emissions data. SB 1137 also specifies the contents of annual reports that operators must submit to CalGEM, and these will be available to the public on a webpage.

7-3.  Will the community have access to annual reports? What is their required content?

Yes, communities will have access to annual reports. SB 1137 requires CalGEM to make information submitted by operators available to the public on a CalGEM internet website. Commencing July 1, 2030, and no less than annually on a date to be determined by CalGEM, SB 1137 requires operators with a well or other production facility or facilities in a health protection zone to provide at least the following information to CalGEM by location in a format that complies with all requirements of the federal Americans with Disabilities Act of 1990 (Public Law 101–336) and its implementing regulations for online viewing:

• The number of and amounts of time the emissions detection system was not operating.

• The number of validated alarms, and the reasons for the alarms.

• The number of leaks that occurred, the time needed to repair the leak, and a brief description of the leak, including the impact on air quality and community exposure.

• The number of times the surrounding community was notified after a leak persisted for 48 hours.

• The number of times and length of time production and injection operations and other use of the facility were suspended due to leaks.

• Any baseline and post drilling groundwater testing performed by location.

Section 8: General Questions

8-1.  Are CARB’s SB 1137 Implementation Regulations duplicative to existing regulations targeting emissions from oil and gas production facilities, such as COGR?

No. SB 1137 regulations and COGR will complement each other. The California Oil and Gas Methane Regulation (COGR) is a regulation of general applicability, both onshore and offshore, that only looks to methane emissions from oil and natural gas facilities. It has periodic inspection requirements (inspections are conducted quarterly), leak thresholds, leak repair deadlines, remote detection of methane plumes, and various reporting and recordkeeping requirements.

By contrast, SB 1137 requires the continuous monitoring of chemical constituents (methane, hydrogen sulfide, and potential toxic) of highest concern for that area for only those facilities within a health protection zone (HPZ). The statute allows methane as surrogate when chemical constituents cannot be continuously monitored. CARB’s SB 1137 regulations will be designed to work with existing regulations by providing an extra layer of protection to communities in the HPZ.

8-2.  Why is SB 1137 needed when there are so many other local, state, and federal LDAR requirements?

Leak detection and repair (LDAR) is not the same as the leak detection and response plans required under SB 1137. Local, state, and federal rules that relate to air emissions, based on set leak thresholds, from all oil and natural gas facilities within their jurisdiction require periodic testing for leaks, reporting of those leaks, and repair deadlines based on the severity of the leak. Local air district rules may address volatile organic compounds (VOCs) released as a result of the leaks, but they do not have provisions relating specifically to continuous monitoring of specific chemical constituents (especially toxics) of concern from oil and natural gas facilities within a certain distance from a sensitive receptor. Communities within 3,200 feet of an oil and natural gas production facility have an increased risk of negative health effects from the facilities’ emissions. Different facility types in different regions will emit different chemical constituents in the event of a leak that are not addressed by standard LDAR. SB 1137 was designed to fill this gap and require more stringent (continuous) monitoring specific to chemical emissions of particular concern in those areas for the protection of public safety.

The continuous monitoring required by SB 1137 would enable the discovery of intermittent leaks sooner than the periodic (typically quarterly) LDAR surveys, and early detection would result in prompt repair of leaks.

8-3. How do SB 1137 requirements and CARB’s associated performance standards compare to COGR, air district, and federal requirements?

The California Oil and Gas Methane Regulation (COGR) and air district rules are subject to U.S. EPA’s approval that such rules are at least as stringent as U.S. EPA’s, so they act alongside federal requirements to address more local emissions concerns. SB 1137 complements COGR and air district rules by imposing additional requirements for operators of oil and gas production facilities within 3,200 feet of a sensitive receptor to prepare a leak detection and response plan that details their continuous emissions detection system for chemical constituents (toxics) as well as their plan for community notification if needed.

8-4. Why are performance standards needed for the emission detection systems? Is there any statutory requirement for CARB to develop performance standards for emission detection systems?

SB 1137 directs CARB to adopt regulations as necessary to implement and set performance standards for the emissions detection system. The performance standards will identify the minimum requirements to ensure the systems fulfill SB 1137 mandates.

SB 1137 requires the systems to effectively, immediately, and reliably alert the operator of leaks before emissions impact the surrounding communities. However, Public Resources Code section 3283, the specific portion granting CARB rulemaking authority, does not give details on how to accomplish these mandates. CARB regulations for performance standards will give those necessary details.

There are two key benefits to having minimum performance standards rather than prescriptive requirements. First, they improve regulatory certainty for operators by identifying the specific criteria CalGEM and CARB will use to approve the monitoring systems. Second, they encourage emission detection system manufacturers to develop cost-effective systems, thus providing oil and gas operators with more choices in selecting the system.

The minimum performance standards will be developed through the rulemaking process, which will provide communities and operators opportunities to suggest options and identify advantages and disadvantages of the different performance standards options, before the Board adopts any standards and before operators need to submit their plans.As mentioned previously, having performance standards rather than prescriptive requirements for specific equipment will provide operators with more choices in monitoring equipment selection.

8-5.  Would CARB’s proposed performance standards require an authorization from U.S. EPA?

No, authorizations are not required for stationary sources, like oil and natural gas production facilities (see below for additional discussion). However, CARB’s oil and gas methane regulation was subject to approval by U.S. EPA for inclusion in the State Implementation Plan in 2017 and is presently being amended to meet the minimum requirements under U.S. EPA’s oil and gas regulation.

California has authority to set its own standards to reduce emissions further to meet federal and state ambient air quality standards and climate change requirements and goals, and to require additional and separate reporting. Section OOOOc of the U.S. EPA’s newly amended oil and gas regulation, published in March 2024, states that CARB must submit their oil and gas regulation to U.S. EPA for U.S. EPA’s approval that the regulation is at least as stringent as U.S. EPA’s (i.e. meet U.S. EPA’s minimum standards) under section 111 of the Clean Air Act. (42 USC 7411.) The proposed SB 1137 performance standards will not require inclusion in the state plan because the federal Clean Air Act’s permitting requirements and the U.S. EPA’s new source performance standards and emissions guidelines, in 40 C.F.R. Part 60, Subparts OOOOa, OOOOb, and OOOOc do not have increased monitoring requirements for facilities near communities nor do they involve any of the emissions guidelines under OOOOc.

8-6. What percentage of oil and gas emissions are made up of benzene and other toxics?

The composition and ratio of any individual volatile organic compound (VOC) vary significantly across oil and gas fields, facility components, and operational processes. This includes toxic compounds like benzene and acrolein as well as non-toxic pollutants like methane. Thus, we cannot say an exact percentage of an individual air toxic on a broad scale, but we can say that air toxics are present across oil and gas emissions, and we are considering all these sources as we develop our proposal for monitoring performance standards.