On November 15, 2017, the Bay Area Air Quality Management District (“BAAQMD”) adopted sweeping new standards to reduce toxic air contaminant (“TAC”) emissions from existing stationary sources. The new rule, Regulation 11 Rule 18, will require assessment of the human health risk caused by TAC emissions from approximately 400 facilities in the BAAQMD including refineries, power plants, cement kilns, foundries, landfills, sewage treatment plants, and chemical plants. Based on these assessments, many of these facilities will be required to reduce emissions by modifying operations or installing costly control devices. In adopting the rule, however, the BAAQMD left open questions regarding implementation of the risk assessment requirement.

The adopted rule implements the most stringent action levels in the nation for 200 TACs based on the risk of cancer and other acute and chronic health impacts in communities surrounding the subject facilities. The maximum cancer risk from any TAC must not exceed 10 excess cancer cases per 1 million residents and the acute and chronic disease index cannot exceed 1.0. BAAQMD has determined that these risk levels are the lowest that are feasible and technically achievable.

In the first stage of rule implementation, health risk assessments (“HRAs”) will be completed for all facilities that the BAAQMD has identified may exceed the risk thresholds. The HRAs will be implemented in two phases. In 2018-2019, approximately 100 high priority facilities, with the greatest existing risks, will be analyzed while the remaining 300 facilities will have HRAs conducted in 2019-2021. Gas stations and facilities that only operate diesel backup generators are exempt from this rule, but will likely be subject to future BAAQMD or state rules to address TAC emissions.

At any facility where the HRA results in risk exceeding the action levels, the facility must submit a Risk Reduction Plan demonstrating how the facility will lower risk to below the action levels.  If it is infeasible to reduce risk below the action levels, the facility must implement toxic best available retrofit control technology (“TBARCT”) on all significant sources.

The Risk Reduction Plans will be reviewed and approved by BAAQMD and are subject to public comment. Upon approval of the Plans, facilities will have five years for implementation and may be granted up to 10 years to address technical feasibility issues or if installation of TBARCT would result in unreasonable economic burdens.

In adopting the new rule, the BAAQMD left a significant implementation issue unresolved. Preparation of accurate HRAs is technically complex and the high toxicity of many of the TACs means that even small inaccuracies in the emission inventory of a facility can result in significant misrepresentations of the modeled risk. BAAQMD staff prefers to manage the HRA process, at least for the largest facilities, through its contractors. Many in industry are concerned that this could lead to inaccurate HRAs and prefer a collaborative approach. The new rule does not prevent or guarantee industry participation in the HRA process. The BAAQMD, however, did commit to implementing a technical dispute resolution committee to resolve disagreements between facilities and BAAQMD staff regarding HRAs.

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