Air quality: standard: hydrogen sulfide.

The response framework changed from a legislative intent statement (the Legislature 'intends' to develop guidelines requiring the state board to act) to a direct mandatory statutory requirement that the state board shall develop the framework in consultation with specified entities.

Removed the provision allowing the state board to adopt additional or updated ambient air quality standards based on threshold levels developed by OEHHA under this bill.

Removed the January 1, 2030 deadline for OEHHA to develop health-based threshold levels for hydrogen sulfide. The new version has no fixed deadline for OEHHA's work.

Removed the requirement that air pollution control districts and air quality management districts must adopt any threshold level developed by OEHHA, and that local environmental and public health agencies may consider them.

Added a new requirement that OEHHA shall update the acute and chronic reference exposure levels for hydrogen sulfide and develop additional health guidance values if the need is identified by the state board during development of the response framework.

Added new numbered requirements to the response framework: develop best practices for measuring hydrogen sulfide levels and using monitoring data; consider how responses may differ for shorter-term incidents versus conditions expected to persist longer; and include an estimate of resources needed for implementation by local and state agencies.

Removed the provision authorizing OEHHA to develop threshold levels for additional air pollutants upon a legislative appropriation, eliminating the pathway for expanding the bill's scope to other pollutants.

Removed Section 3, which stated no reimbursement is required under the California Constitution because local agencies have authority to levy service charges. The bill now states 'State-mandated local program: no' without a separate constitutional reimbursement section.

The mandatory requirement for the state board to conduct a comprehensive review of the hydrogen sulfide standard and adopt an updated standard within 12 months of publishing a report is entirely removed. The state board now only has discretionary authority ('may') to adopt additional or updated standards based on OEHHA threshold levels.

The response framework for addressing hydrogen sulfide exposure events changes from 'intent of the Legislature to develop guidelines that would require' (aspirational) to a direct mandate: 'The state board shall...develop a response framework.' This makes it a binding legal obligation rather than a statement of future legislative intent.

The state board must now evaluate the inadequacies of Acute, 8-hour, and Chronic Reference Exposure Levels specifically for fugitive and natural sources, considering scientific literature on health effects, adequacy of averaging times including frequency and duration of exposures, and influence of local/regional climates and indoor/outdoor settings.

The consultation list for developing the response framework is expanded to include the Office of Emergency Services and regional water quality control boards, in addition to the previously listed entities.

Two new definitions are added: 'fugitive source' (any hydrogen sulfide emission source not currently regulated as a stationary source by a local air district) and 'natural source' (a source occurring in nature as a result of environmental circumstances).

The response framework now specifically targets 'fugitive and natural sources of hydrogen sulfide gas' and 'community preparation and response to hydrogen sulfide exposure events originating from these sources,' and must consider cross-media releases and develop integrated multiagency approaches to identify, address, and reduce these sources.

The bill is restructured from two separate code sections (39607.7 for the standard review and 41514.7 for OEHHA thresholds) into a single section (41514.7), consolidating all provisions in one place.

The state-mandated local program designation appears to change from 'no' to 'yes,' reflecting that the new mandatory response framework imposes costs on local air districts and public health agencies.

The entire data center sales and use tax exemption (Section 6372, Revenue and Taxation Code) was deleted. This had provided a partial tax exemption for equipment used at certified data center facilities meeting job creation, investment, and renewable energy requirements, effective January 1, 2026.

The bill now authorizes OEHHA to develop threshold levels for additional air pollutants using the same considerations, but only upon a legislative appropriation for that purpose.

The bill title was narrowed from covering both the Revenue and Taxation Code (tax exemption) and Health and Safety Code (air pollution) to only the Health and Safety Code. Senator Blakespear was added as co-author.

New Section 41514.7 (Health and Safety Code) requires the Office of Environmental Health Hazard Assessment to develop health-based threshold levels for hydrogen sulfide on or before January 1, 2030, considering acute/subchronic/chronic effects, multiple averaging times (10-minute, 30-minute, 8-hour, 24-hour, chronic), indoor and outdoor exposure, local and regional climates, and corresponding actions such as public notification and local agency response.

The bill expresses legislative intent to develop guidelines requiring the state board, in consultation with multiple entities, to develop a response framework establishing best practices and guidance based on OEHHA's threshold levels.

Air pollution control districts and air quality management districts are required to adopt any threshold levels developed by OEHHA under the new section. Local environmental and public health agencies are authorized (but not required) to consider them.

The state-mandated local program designation changed from 'no' to 'yes,' and a new Section 3 was added stating no reimbursement is required under Article XIII B of the California Constitution because local agencies have authority to levy service charges, fees, or assessments sufficient to pay for the mandated program.

A new hard deadline of January 1, 2030 was established for OEHHA to complete its development of hydrogen sulfide threshold levels. The state board's existing obligation to adopt an updated standard within 12 months of publishing its review report remains unchanged.

New definitions were added for 'local environmental and public health agencies' (any local entity a health officer serves, or any local environmental health agency) and 'office' (OEHHA).

The bill now covers two separate subjects: the existing data center sales tax exemption (Revenue and Taxation Code Section 6372) and a new hydrogen sulfide air quality standard review requirement (Health and Safety Code Section 39607.7).

Requires the State Air Resources Board to conduct a comprehensive review of the current one-hour ambient air quality standard for hydrogen sulfide (0.03 ppm, adopted in 1969) and adopt an updated standard as necessary to protect public health, including sensitive and overburdened communities.

Requires the state board to evaluate at minimum: current scientific literature on acute, subchronic, and chronic health effects; federal, state, and international exposure guidelines; documented exposure conditions in the Tijuana River Valley and Salton Sea regions; adequacy of current averaging times (including potential 8-hour, 24-hour, or chronic standards); and cumulative impacts on environmental justice communities.

Requires at least three public workshops during the review: one in the Tijuana River Valley region, one in the Salton Sea region, and one additional location selected in consultation with overburdened communities.

Requires the state board to consult with local air districts, the Office of Environmental Health Hazard Assessment, the State Department of Public Health, affected tribal governments, and community-based organizations.

After completing the review, the state board must publish a publicly available report on its website, and no later than 12 months after publishing that report, must adopt an updated hydrogen sulfide ambient air quality standard considering multiple averaging times and chronic low-level exposures.

The effective date for the sales tax exemption, the investment requirement start date, and the 'placed in service' requirement were all changed from January 1, 2025 to January 1, 2026.

A new requirement was added (subdivision (c)(7)) that certified data center facilities must have onsite battery storage for the duration of the qualification period.

The definition of 'data center facility' was restructured so that backup power, modular data centers or preassembled components, associated telecommunications and storage systems, and network connections between buildings are now optional features rather than mandatory requirements. Only location within one county, more than 50 percent server use, and uninterruptible power sources with fire suppression and physical security remain required.