Title: Cal. Building Ind. Ass’n v. Bay Area Air Quality Mgmt. Dist.
Citation: N/A
Docket Number: S213478
State: California
Issuer: California Supreme Court
Date: December 17, 2015

1 
Filed 12/17/15 
 
 
IN THE SUPREME COURT OF CALIFORNIA 
 
 
CALIFORNIA BUILDING INDUSTRY 
) 
ASSOCIATION, 
) 
 
 
) 
 
Plaintiff and Respondent, 
) 
 
 
) 
S213478 
 
v. 
) 
 
 
) 
Ct.App. 1/5 
BAY AREA AIR QUALITY 
) 
A135335, A136212 
MANAGEMENT DISTRICT, 
) 
 
) 
Alameda County 
 
Defendant and Appellant. 
) 
Super. Ct. No. RG10548693 
 
____________________________________) 
 
We granted review to address the following question:  Under what 
circumstances, if any, does the California Environmental Quality Act (CEQA) 
(Pub. Resources Code,1 § 21000 et seq.) require an analysis of how existing 
environmental conditions will impact future residents or users of a proposed 
project? 
In light of CEQA‘s text, statutory structure, and purpose, we conclude that 
agencies subject to CEQA generally are not required to analyze the impact of 
existing environmental conditions on a project‘s future users or residents.  But 
when a proposed project risks exacerbating those environmental hazards or 
conditions that already exist, an agency must analyze the potential impact of such 
hazards on future residents or users.  In those specific instances, it is the project’s 
impact on the environment — and not the environment’s impact on the project — 
                                              
1  
All further statutory references are to this code unless otherwise indicated. 
2 
that compels an evaluation of how future residents or users could be affected by 
exacerbated conditions.  Our reading is consistent with certain portions of 
administrative guidelines issued by the California Natural Resources Agency 
(Resources Agency), to whom we owe a measure of deference in a case such as 
this one.   
Moreover, special CEQA requirements apply to certain airport, school, and 
housing construction projects.  In such situations, CEQA requires agencies to 
evaluate a project site‘s environmental conditions regardless of whether the project 
risks exacerbating existing conditions.  The environmental review must take into 
account — and a negative declaration or exemption cannot issue without 
considering — how existing environmental risks such as noise, hazardous waste, 
or wildland fire hazard will impact future residents or users of a project.  That 
these exceptions exist, however, does not alter our conclusion that ordinary CEQA 
analysis is concerned with a project‘s impact on the environment, rather than with 
the environment‘s impact on a project and its users or residents. 
Accordingly, we hold that CEQA does not require an agency to consider 
the impact of existing conditions on future project users except in the 
aforementioned circumstances.  We reverse the Court of Appeal‘s judgment and 
remand for proceedings consistent with our decision. 
I.  BACKGROUND 
The Bay Area Air Quality Management District (District) is a regional 
agency authorized to adopt and enforce regulations governing air pollutants from 
stationary sources such as factories, refineries, power plants, and gas stations in 
the San Francisco Bay Area.  The District‘s purpose is to achieve and maintain 
compliance, in its regional jurisdiction, with state and federal ambient air quality 
3 
standards.  (Health & Saf. Code, §§ 39002, 40000, 40001, subd. (a), 40200.)2  To 
fulfill this purpose, the District monitors air quality, issues permits to certain 
emitters of air pollution, and promulgates rules to control emissions.  (Id., 
§§ 40001, 42300, 42301.5, 42315.) 
The Resources Agency, meanwhile, is the agency with primary 
responsibility for statewide implementation of CEQA.  It carries out this task in 
part by adopting administrative guidelines (Cal. Code Regs., tit. 14, § 15000 et 
seq.)3 that call for other agencies subject to CEQA, such as the District, to develop 
―thresholds of significance‖ for determining ―the significance of environmental 
effects.‖  (Guidelines, § 15064.7, subd. (a).)  In 1999, the District published 
thresholds of significance for certain air pollutants, along with its own regional 
guidelines concerning the use of the thresholds and CEQA air quality issues in 
general, in order to guide those preparing or evaluating air quality impact analyses 
for projects in the San Francisco Bay Area.  The thresholds set levels at which 
toxic air contaminants (TACs) and certain types of particulate matter would be 
deemed environmentally significant. 
A decade later, in 2009, the District drafted new proposed thresholds of 
significance partly in response to the Legislature‘s adoption of laws addressing 
greenhouse gases (GHGs).4  The District cited three factors to justify the new 
                                              
2  
Our recitation of the factual and procedural background is taken largely 
from the opinion of the Court of Appeal. 
3  
All references to ―Guideline‖ or ―Guidelines‖ are to the CEQA Guidelines 
in title 14 of the California Code of Regulations. 
4  
In 2006, the Legislature enacted the California Global Warming Solutions 
Act of 2006 (Health & Saf. Code, § 38500 et seq.), which seeks to achieve a 
reduction of GHG emissions to 1990 levels by 2020.  (Id., § 38550.)  In 2008, the 
Legislature enacted the ―Sustainable Communities and Climate Protection Act.‖  
(Stats. 2008, ch. 728.) 
4 
thresholds:  (1) the existence of more stringent state and federal air quality 
standards that took effect after the District adopted its earlier thresholds, (2) the 
discovery that TACs present a greater health risk than previously thought, and 
(3) growing concerns over global climate change.  A number of organizations, 
businesses, and local governments participated in public hearings, meetings, and 
workshops held by the District regarding the proposed revisions.  One such 
participant was the California Building Industry Association (CBIA), a statewide 
trade association representing homebuilders, architects, trade contractors, 
engineers, designers, and other building industry professionals. 
During the public hearing process, CBIA expressed concern that the 
District‘s proposed thresholds and guidelines were too stringent and would make it 
difficult to complete urban infill projects located near existing sources of air 
pollution.5  CBIA claimed the proposed thresholds would require environmental 
impact reports (EIRs) for many more projects than before, and would result in 
nonapproval of other projects.  If these infill projects were not feasible, CBIA 
argued, development would occur in more suburban areas and result in even more 
pollution from automobile commuter traffic. 
The District was not persuaded.  In June 2010, the District‘s board of 
directors passed resolution No. 2010-06, adopting new thresholds of significance 
for air pollutants, including the TAC ―receptor thresholds‖ and thresholds for 
GHGs and PM2.5 (particulate matter with a diameter of 2.5 microns or less).  The 
District also published new CEQA air quality guidelines, which include the new 
                                              
5  
An urban infill project refers to a project located on a site in an urbanized 
area that meets specified conditions, including that a specified percentage of the 
immediately adjacent parcels or adjoining parcels to the site are developed with 
qualified urban uses, or that the site itself has been previously developed for 
qualified urban uses.  (See § 21061.3.) 
5 
thresholds and suggest methods of assessing and mitigating impacts found to be 
significant.  (District, Cal Environmental Quality Act:  Air Quality Guidelines 
(June 2010).)  
CBIA filed a petition for writ of mandate challenging these thresholds.  
(Code Civ. Proc., § 1085.)  After rejecting CBIA‘s contentions that state law 
preempts the thresholds, the superior court conducted a hearing on the merits of 
the following claims:  (1) the District should have conducted a CEQA review of 
the thresholds before their promulgation because they constitute a ―project‖ within 
the meaning of CEQA; (2) the TAC/PM2.5 risks and hazards thresholds are 
arbitrary and capricious to the extent they unlawfully require an evaluation of the 
impacts the environment would have on a given project; (3) aspects of the 
thresholds are not based on substantial evidence; and (4) the thresholds fail the 
―rational basis‖ test because sufficient evidence does not exist for their approval.   
The superior court determined that the District‘s promulgation of the 2010 
thresholds was indeed a ―project‖ under CEQA, and that the District was therefore 
bound to evaluate the thresholds‘ potential impact on the environment.  Because 
the District issued the thresholds without the required CEQA review, the court 
entered judgment in favor of CBIA without addressing CBIA‘s other arguments.  
The court then issued a writ of mandate directing the District to set aside its 
approval of the thresholds, without addressing CBIA‘s claim that the District‘s 
TAC/PM2.5 thresholds were arbitrary and capricious because they required an 
analysis of how a project would impact future residents or users.  The court also 
awarded CBIA attorney fees under Code of Civil Procedure section 1021.5. 
The Court of Appeal reversed.  In ordering the superior court to vacate its 
writ of mandate, the Court of Appeal concluded, among other things, that the 
District‘s promulgation of the 2010 thresholds was not a project subject to CEQA 
review.  It also rejected CBIA‘s various challenges to the substance of the 
6 
thresholds, including its challenge to the validity of the receptor thresholds — the 
thresholds for ―new receptors‖ consisting of residents and workers who will be 
brought into the area as a result of a proposed project.  CBIA had argued the 
receptor thresholds are invalid because CEQA does not require analysis of the 
impacts that existing hazardous conditions will have on a new project‘s occupants.  
The Court of Appeal more narrowly determined that the receptor thresholds have 
valid applications irrespective of whether CEQA requires an analysis of how 
existing environmental conditions impact a project‘s future residents or users, and 
therefore are ―not invalid on their face.‖  Finding that CBIA was ―no longer a 
successful party,‖ the Court of Appeal reversed the trial court‘s award of attorney 
fees and awarded the District its ordinary costs on appeal. 
We then granted CBIA‘s petition for review, but limited the scope of our 
review to the following question:  Under what circumstances, if any, does CEQA 
require an analysis of how existing environmental conditions will impact future 
residents or users (receptors) of a proposed project?6  
II. DISCUSSION 
 
As this case turns on our interpretation of CEQA statutory provisions 
implemented through the Resources Agency‘s Guidelines, it is helpful at the outset 
to clarify the scope of our analysis before turning to the relevant statutory and 
Guidelines provisions.  We review the Court of Appeal‘s interpretation of the 
statute de novo.  (Abatti v. Imperial Irrigation Dist. (2012) 205 Cal.App.4th 650, 
668.)  Our goal in interpreting CEQA is to adopt the construction that best gives 
                                              
6  
We declined CBIA‘s invitation to review whether the District‘s adoption of 
the 2010 thresholds constituted a project subject to environmental review under 
CEQA, and do not address the Court of Appeal‘s conclusion that the receptor 
thresholds have valid applications. 
7 
effect to the Legislature‘s intended purpose.  (Committee for Green Foothills v. 
Santa Clara County Bd. of Supervisors (2010) 48 Cal.4th 32, 45 (Committee for 
Green Foothills).)  Consistent with that purpose, we interpret CEQA to afford the 
most thorough possible protection to the environment that fits reasonably within 
the scope of its text.  (Laurel Heights Improvement Assn. v. Regents of University 
of California (1988) 47 Cal.3d 376, 390 (Laurel Heights).) 
 
In construing the statute, we also consider the interpretation of the agency 
charged with its implementation.  Even in the absence of quasi-legislative 
regulations,7 we take into account the agency‘s interpretation when we 
independently construe the statute, and afford the agency‘s interpretation the 
deference that is appropriate under the circumstances.  (Yamaha Corp. of America 
v. State Bd. of Equalization (1998) 19 Cal.4th 1, 7 (Yamaha).)  In deciding how 
much weight to give the agency‘s interpretation, we consider the agency‘s 
specialized knowledge and expertise — especially relevant where the statute at 
issue is a complex, technical one — and whether the agency adopted the 
interpretation pursuant to the Administrative Procedure Act.  (Yamaha, at pp. 12-
13.)  Whether the Guidelines are binding or merely reflect the Resources Agency‘s 
interpretation of the statute, we should afford great weight to the Guidelines when 
interpreting CEQA, unless a provision is clearly unauthorized or erroneous under 
the statute.  (Committee for Green Foothills, supra, 48 Cal.4th at p. 48, fn. 12.)  
A. General Overview of CEQA 
CEQA was enacted to advance four related purposes:  to (1) inform the 
government and public about a proposed activity‘s potential environmental 
                                              
7  
Our court has not decided ― ‗whether the Guidelines are regulatory 
mandates or only aids to interpreting CEQA.‘ ‖ (Committee for Green Foothills, 
supra, 48 Cal.4th at p. 48, fn. 12.) 
8 
impacts; (2) identify ways to reduce, or avoid, environmental damage; (3) prevent 
environmental damage by requiring project changes via alternatives or mitigation 
measures when feasible; and (4) disclose to the public the rationale for 
governmental approval of a project that may significantly impact the environment.  
(Tomlinson v. County of Alameda (2012) 54 Cal.4th 281, 285-286 (Tomlinson).)   
 
To further these goals, CEQA requires that agencies follow a three-step 
process when planning an activity that could fall within its scope.  (Tomlinson, 
supra, 54 Cal.4th at p. 286; see Guidelines, § 15002, subd. (k).)  First, the public 
agency must determine whether a proposed activity is a ―project,‖ i.e., an activity 
that is undertaken, supported, or approved by a public agency and that ―may cause 
either a direct physical change in the environment, or a reasonably foreseeable 
indirect physical change in the environment.‖  (§ 21065.)   
 
Second, if the proposed activity is a project, the agency must next decide 
whether the project is exempt from the CEQA review process under either a 
statutory exemption (see § 21080) or a categorical exemption set forth in the 
CEQA Guidelines (see § 21084, subd. (a); Guidelines, § 15300 et seq.).  If the 
agency determines the project is not exempt, it must then decide whether the 
project may have a significant environmental effect.  And where the project will 
not have such an effect, the agency ―must ‗adopt a negative declaration to that 
effect.‘ ‖  (Tomlinson, supra, 54 Cal.4th at p. 286, quoting § 21080, subd. (c); see 
Guidelines, § 15070.)8 
Third, if the agency finds the project ―may have a significant effect on the 
environment,‖ it must prepare an EIR before approving the project.  (§§ 21100, 
                                              
8  
A negative declaration is a ―written statement briefly describing the reasons 
that a proposed project will not have a significant effect on the environment and 
does not require the preparation of an environmental impact report.‖  (§ 21064.) 
9 
subd. (a), 21151, subd. (a), 21080, subd. (d), 21082.2, subd. (d).)  Given the 
statute‘s text, and its purpose of informing the public about potential 
environmental consequences, it is quite clear that an EIR is required even if the 
project‘s ultimate effect on the environment is far from certain.  (Communities for 
a Better Environment v. California Resources Agency (2002) 103 Cal.App.4th 98, 
110 [EIR is required  ― ‗ ―whenever it can be fairly argued on the basis of 
substantial evidence that the project may have significant environmental impact,‖ ‘ 
regardless of whether other substantial evidence supports the opposite 
conclusion‖], disapproved on another ground in Berkeley Hillside Preservation v. 
City of Berkeley (2015) 60 Cal.4th 1086, 1109, fn. 3.)  Determining environmental 
significance ―calls for careful judgment on the part of the public agency involved, 
based to the extent possible on scientific and factual data.‖  (Guidelines, § 15064, 
subd. (b).)  The Guidelines encourage public agencies to develop and publish 
―thresholds of significance‖ (Guidelines, § 15064.7, subd. (a)), which generally 
promote predictability and efficiency when the agencies determine whether to 
prepare an EIR.  (Communities for a Better Environment, at p. 111.) 
When an agency prepares an EIR, it provides public officials and the 
general public with details about a proposed project‘s consequences.  The EIR also 
lists the ways to potentially minimize any significant environmental effects, and 
presents alternatives to the project.  (§ 21061; see § 21002.1, subd. (a).)  By 
making this information available to decision makers and the public at a crucial 
moment when the merits of a project and its alternatives are under discussion, an 
EIR advances not only the goal of environmental protection but of informed self-
government.  (In re Bay-Delta etc. (2008) 43 Cal.4th 1143, 1162 [an EIR ―give[s] 
the public and government agencies the information needed to make informed 
decisions, thus protecting ‗ ―not only the environment but also informed self-
government‖ ‘ ‖].) 
10 
The function CEQA assigns to an EIR, in fact, epitomizes the statute‘s 
focus on informed decisionmaking and self-government.  The statute does not 
necessarily call for disapproval of a project having a significant environmental 
impact, nor does it require selection of the alternative ―most protective of the 
environmental status quo.‖  (San Franciscans Upholding the Downtown Plan v. 
City and County of San Francisco (2002) 102 Cal.App.4th 656, 695.)  Instead, 
when ―economic, social, or other conditions‖ make alternatives and mitigation 
measures ―infeasible,‖ a project may be approved despite its significant 
environmental effects if the lead agency adopts a statement of overriding 
considerations and finds the benefits of the project outweigh the potential 
environmental damage.  (§§ 21002, 21002.1, subd. (c); Guidelines, § 15093; see 
City of Irvine v. County of Orange (2013) 221 Cal.App.4th 846, 855.) 
B. Section 21083 and Guidelines Section 15126.2 
Reflecting the need for further elaboration of these requirements in 
implementation, CEQA entrusts to the Governor‘s Office of Planning and 
Research (OPR) the responsibility of drafting the aforementioned Guidelines.  
Once OPR completes this process, the Secretary of the Resources Agency may 
certify and adopt the Guidelines in compliance with the Government Code.  
(§ 21083, subds. (a), (e), (f); see Guidelines, § 15000 et seq.)9  Section 21083 
                                              
9  
Section 21083 also directs OPR to recommend, at least every two years, 
amendments to the Guidelines.  The statute likewise directs the Resources Agency 
to certify and adopt Guidelines and amendments thereto at least every two years.  
(§ 21083, subd. (f).)  Prior to final certification and adoption of the Guidelines and 
Guidelines amendments, the Secretary of the Resources Agency makes the 
proposed language available to the public and provides for at least a 45-day 
written comment period and public hearings on the proposals.  (§ 21083, 
subds. (e), (f); Gov. Code, §§ 11346.4, 11346.5, 11346.8.)  These public 
comments are considered by the secretary in determining whether to adopt the 
OPR‘s proposed amendments. 
11 
provides the Guidelines ―shall include objectives and criteria for the orderly 
evaluation of projects and the preparation of environmental impact reports and 
negative declarations in a manner consistent with [CEQA].‖  (§ 21083, subd. (a).)  
The Guidelines therefore serve to make the CEQA process tractable for those who 
must administer it, those who must comply with it, and ultimately, those members 
of the public who must live with its consequences.   
What the Guidelines are supposed to contain is also specified in section 
21083.  The Guidelines ―shall specifically include criteria for public agencies to 
follow in determining whether or not a proposed project may have a ‗significant 
effect on the environment.‘ ‖  (§ 21083, subd. (b) (section 21083(b).)  Most 
relevant is the provision‘s express command that ―[t]he criteria shall require a 
finding that a project may have a ‘significant effect on the environment’ if one or 
more of‖ a set of certain conditions exist.  (Ibid., italics added.)  These conditions 
include a ―proposed project[‘s] . . . potential to degrade the quality of the 
environment, curtail the range of the environment, or to achieve short-term, to the 
disadvantage of long-term, environmental goals‖ and circumstances where a 
project‘s ―possible effects . . . are individually limited but cumulatively 
considerable.‖  (Id., subd. (b)(1), (2).)  Section 21083, subdivision (b)(2) defines 
―cumulatively considerable‖ as the ―incremental effects of an individual project 
. . . when viewed in connection with the effects of past projects, the effects of 
other current projects, and the effects of probable future projects.‖  The final 
condition listed under section 21083 is where ―[t]he environmental effects of a 
project will cause substantial adverse effects on human beings, either directly or 
indirectly.‖  (§ 21083, subd. (b)(3) (section 21083(b)(3)), italics added.)  
Through these Guidelines, the Resources Agency gives public agencies a 
more concrete indication of how to comply with CEQA — including whether such 
agencies must determine the impact of existing environmental conditions on a 
12 
proposed project‘s residents and users.  The Guidelines also prove consequential 
given that under section 21082, CEQA requires agencies subject to its provisions 
— such as the District — to adopt ―objectives, criteria and procedures‖ for 
evaluating projects and preparing environmental documents.  These agencies may, 
in turn, adopt the Guidelines by reference to fulfill their statutory responsibilities.  
(§ 21082; see Guidelines, § 15022, subds. (a), (d).)  The Guidelines, in effect, 
enable the Resources Agency to promote consistency in the evaluation process 
that constitutes the core of CEQA.  And because these Guidelines allow the 
Resources Agency to affect how agencies comply with CEQA, they are central to 
the statutory scheme.  (Cf. Citizens of Goleta Valley v. Board of Supervisors 
(1990) 52 Cal.3d 553, 566 [noting that certain ―statutory and judicial concepts are 
carried forward in the Guidelines‖]; East Peninsula Ed. Council, Inc. v. Palos 
Verdes Peninsula Unified School Dist. (1989) 210 Cal.App.3d 155, 171 
[―[B]ecause [CEQA] specifically incorporates the Guidelines pertaining to 
categorical exemptions, the philosophy and policies underlying the categorical 
exemptions should be paramount‖ (italics added)].)   
Especially relevant to the question before us is one such provision of the 
Guidelines, section 15126.2, subdivision (a) (Guidelines section 15126.2(a)).  
Promulgated pursuant to section 21083 of the statute, Guidelines section 
15126.2(a) reflects the Resources Agency‘s interpretation of CEQA.  It calls for an 
EIR to ―identify and focus on the significant environmental effects of the proposed 
project,‖ including ―any significant environmental effects the project might cause 
by bringing development and people into the area affected.‖  (Italics added.)  The 
Guideline then continues by providing an example, indicating that an EIR for a 
project ―on a subdivision astride an active fault line should identify as a significant 
effect the seismic hazard to future occupants of the subdivision‖ because that 
―subdivision would have the effect of attracting people to the location and 
13 
exposing them to the hazards found there.‖  (Ibid.)  The Guideline likewise calls 
for an EIR to ―evaluate any potentially significant impacts of locating 
development in other areas susceptible to hazardous conditions (e.g., floodplains, 
coastlines, wildfire risk areas) as identified in authoritative hazard maps, risk 
assessments or in land use plans addressing such hazards areas.‖  (Ibid.)   
Guidelines section 15126.2(a), in short, indicates that CEQA generally 
requires an evaluation of environmental conditions and hazards existing on a 
proposed project site if such conditions and hazards may cause substantial adverse 
impacts to future residents or users of the project.  Given that this Guideline seems 
to furnish a specific answer to the question before us, it is perhaps not surprising 
that the District and CBIA dispute its validity.10   
C. 
CEQA‘s General Rule  
The District and CBIA disagree about this Guideline because they diverge 
on how to interpret section 21083.  The core of their disagreement is what the 
statute means when it provides that ―a project may have a ‗significant effect on the 
environment‘ ‖ (§ 21083(b)) if ―[t]he environmental effects of a project will cause 
substantial adverse effects on human beings, either directly or indirectly.‖  
(§ 21083(b)(3).)  The District reads the statutory language to encompass the 
question of how existing environmental conditions or hazards in the vicinity of a 
proposed project might substantially, and adversely, impact future residents or 
users.  Under this view, when existing environmental conditions on or near the 
proposed project site pose hazards to humans brought to the site by the project, the 
                                              
10  
OPR represents it will not suggest any changes to Guidelines section 
15126.2 pending this court‘s decision in the instant case.  (OPR, Possible Topics 
to be Addressed in the 2014 CEQA Guidelines Update (Dec. 30, 2013) § IV, p. 7.)  
14 
project may have potentially significant environmental effects requiring 
evaluation.   
CBIA takes a contrasting view.  It asserts that section 21083(b)(3)‘s 
reference to the ―environmental effects of a project‖ only applies to a project‘s 
effects on the environment, and does not include the effects of a site‘s 
environment on a project, or on its residents and users.11  CBIA contends that the 
District‘s construction contradicts CEQA‘s clear language and distorts the intent 
of the statutory scheme, and that adopting it would ―impose[ ] procedural or 
substantive requirements beyond those explicitly stated‖ in CEQA or its 
Guidelines.  (§ 21083.1.)   
In light of CEQA‘s text and structure, we conclude that CEQA generally 
does not require an analysis of how existing environmental conditions will impact 
a project‘s future users or residents.  The District emphasizes, correctly, that 
CEQA addresses human health and safety.  Section 21083(b)(3)‘s express 
language, for example, requires a finding of a ― ‗significant effect on the 
environment‘ ‖ (§ 21083(b)) whenever the ―environmental effects of a project will 
cause substantial adverse effects on human beings, either directly or indirectly.‖  
(§ 21083(b)(3), italics added.)  And the Legislature has made clear — in 
declarations accompanying CEQA‘s enactment — that public health and safety are 
of great importance in the statutory scheme.  (E.g., §§ 21000, subds. (b), (c), (d), 
(g), 21001, subds. (b), (d) [emphasizing the need to provide for the public‘s 
                                              
11  
CBIA uses the term ―reverse CEQA‖ to refer to an evaluation of how 
existing conditions might impact a project‘s future residents or users.  We find this 
term misleading and inapt.  Because CEQA does sometimes require analysis of the 
effect of existing conditions on a project‘s future residents or users, such analysis 
is not the ―reverse‖ of what CEQA mandates.  (See pp. 21-22, post.)   
15 
welfare, health, safety, enjoyment, and living environment].)  Still, the District 
reads too much into the phrase ―environmental effects of a project.‖ 
The District‘s reading of that phrase goes too far despite all the reasons for 
us to give the Resources Agency‘s interpretation — an interpretation broadly 
consistent with that of the District — special weight.  The statute does not provide 
enough of a basis to suggest that the term ―environmental effects‖ as used in this 
context is meant, as a general matter, to encompass these broader considerations 
associated with the health and safety of a project‘s future residents or users.   
Section 21060.5 defines ―environment‖ as ―the physical conditions which exist 
within the area which will be affected by a proposed project, including land, air, 
water, minerals, flora, fauna, noise, objects of historic or aesthetic significance.‖  
(§ 21060.5.)  Given the text of section 21083 and other relevant provisions of the 
statutory scheme to which it belongs — including CEQA‘s statute-wide definition 
of ―environment‖ — the phrase in question is best interpreted as limited to those 
impacts on a project‘s users or residents that arise from the project‘s effects on the 
environment.  Even if one reads into CEQA‘s definition of ―environment‖ a 
concern with people — a reading that, notwithstanding section 21060.5, is 
conceivable given the Legislature‘s interest in public health and safety — section 
21083 does not contain language directing agencies to analyze the environment‘s 
effects on a project.  Requiring such an evaluation in all circumstances would 
impermissibly expand the scope of CEQA.   
The rest of the statute‘s relevant provisions underscore why.  Despite the 
statute‘s evident concern with protecting the environment and human health, its 
relevant provisions are best read to focus almost entirely on how projects affect 
the environment.  (E.g., §§ 21060.5 [defining environment], 21068 [― ‗Significant 
effect on the environment‘ means a substantial, or potentially substantial, adverse 
change in the environment‖], 21083(b)(1) [directing that a project shall be found 
16 
to have a ― ‗significant effect on the environment‘ ‖ if it ―has the potential to 
degrade the quality of the environment‖].)  Indeed, the key phrase ―significant 
effect on the environment‖ is explicitly defined by statute in a manner that does 
not encompass the environment‘s effect on the project.  (§ 21068 [― ‗Significant 
effect on the environment‘ means a substantial, or potentially substantial, adverse 
change in the environment‖].)  And nowhere in the statute is there any provision 
that cuts against the specificity of that definition by plainly delegating power for 
the agency to determine whether a project must be screened on the basis of how 
the environment affects its residents or users.   
Consider the alternative:  stretching the definition so it encompasses the 
analysis of how environmental conditions could affect a project‘s future residents 
— the kind of analysis that the Guidelines purport to require — would require us 
to define ―environmental effects of a project‖ in a manner that all but elides the 
word ―environmental.‖  That approach, in turn, would allow the phrase to 
encompass nearly any effect a project has on a resident or user.  Given the 
sometimes costly nature of the analysis required under CEQA when an EIR is 
required, such an expansion would tend to complicate a variety of residential, 
commercial, and other projects beyond what a fair reading of the statute would 
support. 
With this holding in mind, we must distinguish between requirements that 
consider the environment’s effects on a project and those that contemplate the 
project’s impacts on the existing environment.  The former, in light of our analysis 
of section 21083 and other relevant language in CEQA, are invalid.  The latter, 
however, are valid and entirely consistent with CEQA‘s concerns about 
environmental protection, public health, and deliberation.  Moreover, and 
17 
consistent with CEQA‘s general rule, we note that the statute does not proscribe 
consideration of existing conditions.12  In fact, CEQA calls upon an agency to 
evaluate existing conditions in order to assess whether a project could exacerbate 
hazards that are already present.  Accordingly, we find that the following 
sentences of Guidelines section 15126.2(a) — challenged by CBIA as 
unauthorized under the statute13 — are valid under CEQA:  ―The EIR shall also 
analyze any significant environmental effects the project might cause by bringing 
development and people into the area affected. . . .  Similarly, the EIR should 
evaluate any potentially significant impacts of locating development in other areas 
susceptible to hazardous conditions (e.g., floodplains, coastlines, wildfire risk 
areas) as identified in authoritative hazard maps, risk assessments or in land use 
plans addressing such hazards areas.‖   
                                              
12  
Nor, for that matter, does CEQA prohibit an agency from considering –– as 
part of an environmental review for a project it proposes to undertake –– how 
existing conditions might impact a project‘s future users or residents.  Indeed, it 
appears that such an analysis had been widely understood to be an integral aspect 
of CEQA review for three decades.  (OPR, CEQA: The California Environmental 
Quality Act:  Law and Guidelines 1984 (Jan. 1984) Discussion of amendments, 
Guidelines former § 15126, p. 137 [dismissing as early as 1983 the alleged 
―artificial distinction‖ between examining ―the effects of the project on the 
environment‖ and ―the effects of the environment on the project‖].)    
13  
CBIA contends that the following sentences of Guidelines section 
15126.2(a) are invalid:  ―The EIR shall also analyze any significant environmental 
effects the project might cause by bringing development and people into the area 
affected.  For example, an EIR on a subdivision astride an active fault line should 
identify as a significant effect the seismic hazard to future occupants of the 
subdivision.  The subdivision would have the effect of attracting people to the 
location and exposing them to the hazards found there.  Similarly, the EIR should 
evaluate any potentially significant impacts of locating development in other areas 
susceptible to hazardous conditions (e.g., floodplains, coastlines, wildfire risk 
areas) as identified in authoritative hazard maps, risk assessments or in land use 
plans addressing such hazards areas.‖  (Guidelines, § 15126.2(a).)   
18 
These sentences are valid to the extent they call for evaluating a project‘s 
potentially significant exacerbating effects on existing environmental hazards — 
effects that arise because the project brings ―development and people into the area 
affected.‖  Both CEQA and the Guideline call explicitly for an analysis of a 
project‘s effects on the environment.  In this respect, the Resources Agency‘s 
directive is consistent with section 21083(b)(3)‘s plain language, as the Guideline 
contemplates analyzing those existing conditions impacted directly by a project‘s 
siting or development.  Moreover, both sentences reflect the Resources Agency‘s 
reasonable construction of CEQA.  We defer to that interpretation, finding it not to 
be proscribed by the statutory language. 
Indeed, the statutory language emphasizes how the analysis of a project‘s 
potential to exacerbate existing conditions is not an exception to, but instead a 
consequence of, CEQA‘s core requirement that an agency evaluate a project‘s 
impact on the environment.  An example may be illuminating.  Suppose that an 
agency wants to locate a project next to the site of a long-abandoned gas station.  
For years, that station pumped gasoline containing methyl tertiary-butyl ether 
(MTBE), an additive — now banned by California — that can seep into soil and 
groundwater.  (See Western States Petroleum Assn. v. State Dept. of Health 
Services (2002) 99 Cal.App.4th 999, 1003; Cal. Code Regs., tit. 13, § 2262.6, 
subd. (a) [prohibiting the addition of MTBE to gasoline starting Dec. 31, 2003].)  
Without any additional development in the area, the MTBE might well remain 
locked in place, an existing condition whose risks — most notably the 
contamination of the drinking water supply — are limited to the gas station site 
and its immediate environs.  But by virtue of its proposed location, the project 
threatens to disperse the settled MTBE and thus exacerbate the existing 
contamination.  The agency would have to evaluate the existing condition — here, 
the presence of MTBE in the soil — as part of its environmental review.  Because 
19 
this type of inquiry still focuses on the project’s impacts on the environment — 
how a project might worsen existing conditions — directing an agency to evaluate 
how such worsened conditions could affect a project‘s future users or residents is 
entirely consistent with this focus and with CEQA as a whole.   
 
These Guideline sentences reflect the Resources Agency‘s reading of 
CEQA — a reading made clear in 2009 when the agency added the final sentence 
of Guidelines section 15126.2(a).  (Cal. Natural Resources Agency, Final 
Statement of Reasons for Regulatory Action:  Amendments to the State CEQA 
Guidelines Addressing Analysis and Mitigation of Greenhouse Gas Emissions 
Pursuant to SB97 (Dec. 2009) pp. 42-43 [―[A] lead agency should analyze the 
effects of bringing development to an area that is susceptible to hazards such as 
flooding and wildfire, both as such hazards currently exist or may occur in the 
future. . . . [¶] . . . [T]he addition to [Guidelines section 15126.2(a)] contemplates 
hazards which the presence of a project could exacerbate‖].) 
 
Two factors add weight to the Resources Agency‘s interpretation of the 
statute.  First, an agency‘s expertise and technical knowledge, especially when it 
pertains to a complex technical statute, is relevant to the court‘s assessment of the 
value of an agency interpretation.  (Yamaha, supra, 19 Cal.4th at p. 12.)  Because 
of its longstanding statutory role as the agency with primary responsibility for 
statewide implementation of CEQA, the Resources Agency is precisely the kind of 
agency that accumulates specialized knowledge of such an intricate statute and the 
trade-offs involved in its implementation.  (Cf. Western States Petroleum Assn. v. 
Superior Court (1995) 9 Cal.4th 559, 572-573 [administrative agency 
implementing CEQA merits deference]; In re Dannenberg (2005) 34 Cal.4th 
1061, 1108 (dis. opn. of Moreno, J.) [―deference is particularly owing when the 
statutory interpretation implicates administrative agency expertise‖].)  The statute 
itself recognizes the primacy of the Resources Agency:  the agency must certify 
20 
and adopt the Guidelines that bind public agencies as they navigate the often 
technical and complex waters of CEQA.  (§ 21083, subd. (e); see Guidelines, 
§ 15000 [―These Guidelines are binding on all public agencies in California‖].) 
 
Second, the Resources Agency adopted the Guidelines pursuant to the 
California Administrative Procedure Act (APA).  (Gov. Code, § 11340 et seq.)  
The APA subjects potential agency interpretations to procedural safeguards that 
foster accuracy and reliability.  (See Yamaha, supra, 19 Cal.4th at p. 13.)  Section 
21083 prohibits the Resources Agency from adopting the Guidelines without 
certain of these APA safeguards, including notice, public discussion, and an 
opportunity to comment.  (§ 21083, subd. (e); Gov. Code, §§ 11346.4, 11346.5, 
11346.8.)  The Guidelines are a product of this process, promulgated in 
accordance with these important safeguards.  (See, e.g., Cal. Reg. Notice Register 
97, No. 41-Z, pp. 1956-1957 [notice of proposed regulatory action, setting forth 
the dates and specifications of public hearings, and inviting comments from 
interested persons].)  As a result, the Resources Agency‘s interpretation, as 
embodied in Guidelines section 15126.2(a), carries additional weight.   
 
But such weight may sometimes fail to tip the interpretive scale.  While 
these two sentences withstand scrutiny, the remainder of the challenged portion of 
the Guidelines goes astray, imposing a requirement too far removed from 
evaluating a project‘s impacts on the environment.  Accordingly, whatever 
deference we owe to the Resources Agency‘s interpretation is not enough to save 
the following sentences of section 15126.2(a), which we find clearly erroneous 
and unauthorized under CEQA:  ―[A]n EIR on a subdivision astride an active fault 
line should identify as a significant effect the seismic hazard to future occupants of 
the subdivision.  The subdivision would have the effect of attracting people to the 
location and exposing them to the hazards found there.‖  These sentences are 
21 
inconsistent with section 21083‘s consideration of significant environmental 
effects. 
D. Exceptions to the General Rule  
Although CEQA does not generally require an evaluation of the effects of 
existing hazards on future users of the proposed project, it calls for such an 
analysis in several specific contexts involving certain airport (§ 21096) and school 
construction projects (§ 21151.8), and some housing development projects 
(§§ 21159.21, subds. (f), (h), 21159.22, subds. (a), (b)(3), 21159.23, 
subd. (a)(2)(A), 21159.24, subd. (a)(1), (3), 21155.1, subd. (a)(4), (6).  
Section 21096 requires a lead agency to use certain technical resources 
when addressing airport-related safety hazards and noise problems in EIRs for 
projects near airports (§ 21096, subd. (a)), and prohibits a lead agency from 
adopting a negative declaration without considering ―whether the project will 
result in a safety hazard or noise problem for persons using the airport or for 
persons residing or working in the project area.‖  (§ 21096, subd. (b).)  Section 
21151.8 mandates certain methods to determine if school sites are located on or 
near sources of hazardous substances or waste or in close proximity to freeways or 
other operations that might emit hazardous emissions.  (§ 21151.8, subd. (a), 
(a)(2)(A) [detailing health and safety risks and hazardous conditions and setting 
forth the process for consulting with air quality districts and other agencies].)   
A separate cluster of statutes limits the availability of CEQA exemptions 
where future residents or users of certain housing development projects may be 
harmed by existing conditions.  These limits on exemptions extend to projects 
located on sites that will expose future occupants to certain hazards and risks — 
including the release of hazardous substances and sites subject to wildland fire, 
seismic, landslide or flood hazards — unless (in some cases) the hazards and risks 
can be removed or mitigated to insignificant levels.  (E.g., §§ 21159.21, subds. (f), 
22 
(h), 21159.22, subds. (a), (b)(3) [agricultural employee housing], 21159.23, 
subd. (a)(2)(A) [affordable to low-income housing], 21159.24, subd. (a)(1), (3) 
[infill housing].)  Transit priority projects are treated in similar fashion, subject to 
the same health and safety constraints that limit exemptions for other housing 
projects.  (E.g., § 21155.1, subd. (a)(4), (6) [project meeting same environmental 
criteria, including where the project site is not subject to onsite hazardous 
substances or fire or seismic risk, may qualify as a sustainable communities 
project, which excuses further CEQA compliance].)  Like the statutes governing 
certain school and airport construction projects, these statutes reflect an express 
legislative directive to consider whether existing environmental conditions might 
harm those who intend to occupy or use a project site.    
The District argues that these statutes ―demonstrate the legislative 
understanding that exposing people to [certain existing hazards and] conditions is 
a potentially significant environmental effect.‖  We find otherwise:  these statutes 
constitute specific exceptions to CEQA‘s general rule requiring consideration only 
of a project‘s effect on the environment, not the environment‘s effects on project 
users.  Accordingly, we cannot, as the District urges, extrapolate from these 
statutes an overarching, general requirement that an agency analyze existing 
environmental conditions whenever they pose a risk to the future residents or users 
of a project.      
E. Previous Case Law 
CBIA cites four Court of Appeal decisions in support of its position:  Baird 
v. County of Contra Costa (1995) 32 Cal.App.4th 1464; City of Long Beach v. Los 
Angeles Unified School Dist. (2009) 176 Cal.App.4th 889; South Orange County 
Wastewater Authority v. City of Dana Point (2011) 196 Cal.App.4th 1604; and 
Ballona Wetlands Land Trust v. City of Los Angeles (2011) 201 Cal.App.4th 455.  
23 
The conclusion that we reach today is not inconsistent with these cases, all of 
which implicitly held that CEQA does not generally require an agency to analyze 
how existing hazards or conditions might impact a project‘s users or residents.  
Further, these Courts of Appeal did not have occasion to consider — and therefore 
did not rule out — the exceptions to the general rule that we elucidate here.   
24 
 
III. DISPOSITION 
For the foregoing reasons, we hold that CEQA does not generally require 
an agency to consider the effects of existing environmental conditions on a 
proposed project‘s future users or residents.  What CEQA does mandate, 
consistent with a key element of the Resources Agency‘s interpretation, is an 
analysis of how a project might exacerbate existing environmental hazards.  
CEQA also requires such an analysis where the project in question falls into 
certain specific statutory categories governing school, airport, and certain housing 
projects under sections 21151.8, 21096, 21159.21, 21159.22, 21159.23, 21159.24, 
and 21155.1.  Accordingly, we find Guidelines section 15126.2(a) valid only in 
part. 
The Court of Appeal denied CBIA‘s request for writ relief on a variety of 
grounds, and it reversed the superior court‘s decision awarding CBIA attorney 
fees.  But the court‘s analysis of CBIA‘s petition for writ relief did not address 
certain potentially important arguments for and against such relief in light of 
CEQA‘s requirements as we interpret them here.  We reverse the Court of 
Appeal‘s judgment and remand so that it may have an opportunity to address these 
issues to the extent necessary in light of today‘s holding.   
 
 
 
 
 
 
CUÉLLAR, J. 
 
WE CONCUR:  
 
CANTIL-SAKAUYE, C. J. 
WERDEGAR, J. 
CHIN, J. 
CORRIGAN, J. 
LIU, J. 
KRUGER, J. 
 
1 
 
See last page for addresses and telephone numbers for counsel who argued in Supreme Court. 
 
Name of Opinion California Building Industry Association v Bay Area Air Quality Management District 
__________________________________________________________________________________ 
 
Unpublished Opinion 
Original Appeal 
Original Proceeding 
Review Granted XXX 218 Cal.App.4th 1171 
Rehearing Granted 
 
__________________________________________________________________________________ 
 
Opinion No. S213478 
Date Filed: December 17, 2015 
__________________________________________________________________________________ 
 
Court: Superior 
County: Alameda 
Judge: Frank Roesch 
 
__________________________________________________________________________________ 
 
Counsel: 
 
Brian C. Bunger, Randi L. Wallach; Shute, Mihaly & Weinberger, Ellison Folk and Erin B. Chalmers for 
Defendant and Appellant. 
 
Matthew Vespa and Kevin P. Bundy for Sierra Club, Center for Biological Diversity, the Natural 
Resources Defense Council and the Planning and Conservation League as Amici Curiae on behalf of 
Defendant and Appellant. 
 
Burke, Williams & Sorensen, Thomas B. Brown and Matthew D. Visick for League of California Cities 
and California State Association of Counties as Amici Curiae on behalf of Defendant and Appellant. 
 
Kurt R. Wise, Barbara B. Baird, Veera Tyagi and Ruby Fernandez for South Coast Air Quality 
Management District as Amicus Curiae on behalf of Defendant and Appellant. 
 
Earthjustice and Adriano L. Martinez for Communities for a Better Environment as Amicus Curiae on 
behalf of Defendant and Appellant. 
 
Wittwer Parkin, William P. Parkin and Jonathan Wittwer for California Chapter of the American Planning 
Association and California Association of Environmental Professionals as Amici Curiae on behalf of 
Defendant and Appellant. 
 
Thomas E. Montgomery, County Counsel, and Paula Forbis, Deputy County Counsel, for San Diego 
County Air Pollution Control District as Amicus Curiae on behalf of Defendant and Appellant. 
 
Paul Campos; Cox, Castle & Nicholson, Michael H. Zischke, Andrew B. Sabey and Christian H. Cebrian 
for Plaintiff and Respondent. 
 
 
2 
 
 
 
 
 
Page 2 – counsel continued – S213478 
 
Counsel: 
 
Perkins Coie, Stephen L. Kostka and Geoffrey L. Robinson for Center for Creative Land Recycling, 
Burbank Housing, Bridge Housing, First Community Housing, Nonprofit Housing Association of Northern 
California, San Francisco Housing Action Coalition, California Infill Builders Federation, Bay Area 
Council, Bay Planning Coalition, East Bay Leadership Council, Orange County Business Council, San 
Mateo County Economic Development Association and Silicon Valley Leadership Group as Amici Curiae 
on behalf of Plaintiff and Respondent. 
 
Miller Starr Regalia, Arthur F. Coon and Matthew C. Henderson for League of California Cities , County 
of Tulare, County of Kings and County of Solano as Amice Curiae. 
 
3 
 
 
 
 
 
Counsel who argued in Supreme Court (not intended for publication with opinion): 
 
Ellison Folk 
Shute, Mihaly & Weinberger 
396 Hayes Street 
San Francisco, CA  94102 
(415) 552-7272 
 
Andrew B. Sabey 
Cox, Castle & Nicholson 
555 California Street, 10th Floor 
San Francisco, CA  94104-1513 
(415) 262-5100