Environmental Scientist Jobs in the United States
Per Se Group
Houston, TX
Demonstrate proficiency in technical writing, reviewing, and editing complex documents related to resource topics such as habitat assessments, wetland delineations, Phase I ESAs, and NEPA documents. Guide clients through the USACE permitting process, including Nationwide Permits, Individual Permits, and other navigation-related permits, providing strategic advice on compliance and permitting.
Whitman, Requardt & Associates, LLP
Raleigh, NC
The candidate will also lead Section 404/401 permitting, coordinate with regulatory agencies and clients, conduct permit compliance monitoring, conduct bat bridge inspections, conduct surveys for invasive species, prepare invasive species management plans, assist with stream stabilization/restoration projects, mentor and train junior staff, and any other services as required by specific projects. We are seeking the very best and most talented to join our team - help us take on today’s infrastructure challenges, develop advanced vision and innovative ideas, and design solutions for resilient, sustainable, efficient and effective multi-modal infrastructure improving and connecting our Communities, States, Countries, and World.
Mabbett & Associates, Inc.
$100000 - $120000
Huntsville, AL
Strong NEPA experience, including Environmental Impact Statements (EIS), cultural resources/Section 106, environmental compliance (to include air quality and permitting), and experience conducting environmental compliance audits. Mabbett is a U.S. Small Business Administration Certified Service-Disabled Veteran-Owned Small Business headquartered in Stoneham, Massachusetts with regional offices located in Rhode Island, New York, South Carolina, and Virginia.
Whitman, Requardt & Associates, LLP
Mechanicsburg, PA
A copy of current, or most recent, school transcript (If you are applying via a 3rd party site that does not allow attachments, please email transcript to careers@wrallp.com. Duties may include: Walking and navigating across rough or uneven terrain such as mud, rocks, grass, dirt, steep hillsides, stream banks, heavily wooded areas, and other unpaved surfaces.
Boeing
$129200 - $174800
Saint Charles, MO
The Boeing Company also provides eligible employees with an opportunity to enroll in a variety of benefit programs, generally including health insurance, flexible spending accounts, health savings accounts, retirement savings plans, life and disability insurance programs, and a number of programs that provide for both paid and unpaid time away from work. Primary responsibilities: Develops and validates electromagnetic compatibility (EMC) and electromagnetic interference (EMI) requirements for various communication, sensor, electronic warfare and other electromagnetic systems, subsystems, components, interconnects and structures.
PPM Consultants, Inc
Altamonte Springs, FL
Candidates will primarily provide environmental compliance, permitting and technical support to clients across several industries (Oil & Gas, Chemical, Manufacturing, Forest Products, etc.). This is a wonderful opportunity for self-starters who enjoy being part of a valuable team that provides multi-media environmental consulting and compliance support to a variety of industrial clients.
Naval Nuclear Laboratory
$63300 - $96900
Niskayuna, NY
High school diploma or equivalent and a minimum of 4 years of relevant experience; or Associates degree from an accredited college or university in a related field and a minimum of 2 years of relevant experience; or Journeymans Papers in a related field and a minimum of 2 years of relevant experience; or Qualification as a Naval Nuclear Propulsion Operator (or commercial nuclear equivalent) and a minimum of 2 years of relevant experience; or Bachelors degree from an accredited college or university in a related field. Naval Nuclear Laboratory personnel are FMP employees who work at four DOE facilities: Bettis Atomic Power Laboratory, Knolls Atomic Power Laboratory, Kenneth A. Kesselring Site, and Naval Reactors Facility, and at the U.S. Department of Defense-owned Nuclear Power Training Unit-Charleston.
L3Harris Technologies
Fort Wayne, IN
With customers’ mission-critical needs always in mind, our employees deliver end-to-end technology solutions connecting the space, air, land, sea and cyber domains in the interest of national security. By submitting your resume for this position, you understand and agree that L3Harris Technologies may share your resume, as well as any other related personal information or documentation you provide, with its subsidiaries and affiliated companies for the purpose of considering you for other available positions.
Naval Nuclear Laboratory
$105200 - $164400
Niskayuna, NY
Bachelors degree from an accredited college or university in a related technical, engineering or science field and a minimum of 9 years of relevant experience; or Masters degree from an accredited college or university in a related technical, engineering or science field and a minimum of 7 years of relevant experience; or Doctorate degree from an accredited college or university in a related technical, engineering or science field and a minimum of 3 years of relevant experience; or Currently an Principal Reactor Training Engineer, Refueling Engineer, or Field (RPCO) Engineer at the Company. Naval Nuclear Laboratory personnel are FMP employees who work at four DOE facilities: Bettis Atomic Power Laboratory, Knolls Atomic Power Laboratory, Kenneth A. Kesselring Site, and Naval Reactors Facility, and at the U.S. Department of Defense-owned Nuclear Power Training Unit-Charleston.
Naval Nuclear Laboratory
$105200 - $164400
Niskayuna, NY
Bachelors degree from an accredited college or university in a related technical, engineering or science field and a minimum of 9 years of relevant experience; or Masters degree from an accredited college or university in a related technical, engineering or science field and a minimum of 7 years of relevant experience; or Doctorate degree from an accredited college or university in a related technical, engineering or science field and a minimum of 3 years of relevant experience; or Currently an Principal Reactor Training Engineer, Refueling Engineer, or Field (RPCO) Engineer at the Company. Additional areas of opportunity include: Ensure compliance with Federal/State regulations and applicable DOE Orders, e.g., Consolidated State Facility Air Permit (CASFP), State Pollution Discharge Elimination System (SPDES), Municipal Separate Storm Sewer System (MS4), Resource Conservation and Recovery Act (RCRA), Sanitary Sewage, Petroleum Bulk Storage (PBS), Asbestos NESHAP Notifications, National Environmental Policy Act (NEPA), and PCBs.
Naval Nuclear Laboratory
$105200 - $164400
Niskayuna, NY
Bachelors degree from an accredited college or university in a related technical, engineering or science field and a minimum of 9 years of relevant experience; or Masters degree from an accredited college or university in a related technical, engineering or science field and a minimum of 7 years of relevant experience; or Doctorate degree from an accredited college or university in a related technical, engineering or science field and a minimum of 3 years of relevant experience; or Currently a Principal Reactor Training Engineer, Refueling Engineer, or Field (RPCO) Engineer at the Company. Naval Nuclear Laboratory personnel are FMP employees who work at four DOE facilities: Bettis Atomic Power Laboratory, Knolls Atomic Power Laboratory, Kenneth A. Kesselring Site, and Naval Reactors Facility, and at the U.S. Department of Defense-owned Nuclear Power Training Unit-Charleston.
Southwest Research Institute
San Antonio, TX
Daily and Monthly Responsibilities: Evaluate and quantify hazards, consequences (including dose and estimated health effects), and risks from external and internal exposure to radiation from radioactive materials in air, water, and soil or in packages for storage or transportation of radioactive materials. Objectives of this Role: For the U.S. Nuclear Regulatory Commission (NRC) and other clients, perform technical and regulatory evaluations for ensuring the safety of nuclear facilities, nuclear materials processing and management, and radioactive waste disposal.
Pace Analytical Services
$22
Minneapolis, MN
Ability to perform work in a lab or office setting, remain standing for long periods while conducting tests, work around strong smells, and wear personal protective equipment while handling samples (e.g., lab coat, safety glasses and gloves; all PPE provided by Pace®). See Pace Analytical Privacy Policy at https://www.pacelabs.com/privacy-policy/ and SonicJobs Privacy Policy at https://www.sonicjobs.com/us/privacy-policy and Terms of Use at https://www.sonicjobs.com/us/terms-conditions.
Pace Analytical Services
$20.2
Westborough, MA
Ability to perform work in a lab or office setting, remain standing for long periods while conducting tests, work around strong smells, and wear personal protective equipment while handling samples (e.g., lab coat, safety glasses and gloves; all PPE provided by Pace®). See Pace Analytical Privacy Policy at https://www.pacelabs.com/privacy-policy/ and SonicJobs Privacy Policy at https://www.sonicjobs.com/us/privacy-policy and Terms of Use at https://www.sonicjobs.com/us/terms-conditions.
Pace Analytical Services
$20.2
Mansfield, MA
Ability to perform work in a lab or office setting, remain standing for long periods while conducting tests, work around strong smells, and wear personal protective equipment while handling samples (e.g., lab coat, safety glasses and gloves; all PPE provided by Pace®). Join us as a Scientist I in our Metals department, where you'll put your love of science to work performing and overseeing projects within the wet chemistry department of our environmental testing laboratory.
Naval Nuclear Laboratory
$77900 - $119300
Niskayuna, NY
High school diploma or equivalent and a minimum of 7 years of relevant experience; or Associates degree from an accredited college or university in a related field and a minimum of 5 years of relevant experience; or Journeymans Papers in a related field and a minimum of 5 years of relevant experience; or Qualification as a Naval Nuclear Propulsion Operator (or commercial nuclear equivalent) and a minimum of 5 years of relevant experience; or Bachelors degree from an accredited college or university in a related field and a minimum of 3 years of relevant experience. Naval Nuclear Laboratory personnel are FMP employees who work at four DOE facilities: Bettis Atomic Power Laboratory, Knolls Atomic Power Laboratory, Kenneth A. Kesselring Site, and Naval Reactors Facility, and at the U.S. Department of Defense-owned Nuclear Power Training Unit-Charleston.
Vaco LLC
$120000 - $130000
Afton, TN
Key responsibilities include the design, implementation, and oversight of EHS policies, procedures, and programs; providing technical expertise related to environmental compliance and employee safety; managing EHS due diligence for acquisitions and divestitures; monitoring and improving employee health and safety performance; and coordinating with regulatory agencies, consultants, and legal counsel to manage compliance risks and obligations. Determining compensation for this role (and others) at Vaco by Highspring depends upon a wide array of factors including but not limited to: the individual’s skill sets, experience and training; licensure and certification requirements; office location and other geographic considerations; other business and organizational needs.
JT4 LLC
Las Vegas, NV
Some jobs may require a candidate to be eligible for a government security clearance, state-issued driver's license or other licenses / certifications and the inability to obtain and maintain the required clearance, license or certification may affect an employee's ability to maintain employment. JT4 develops and maintains realistic, integrated test and training environments and prepares our nation's war-fighting aircraft, weapons systems, and aircrews for today's missions and tomorrow's global challenges.
JT4 LLC
Edwards Air Force Base, CA
Some jobs may require a candidate to be eligible for a government security clearance, state-issued driver's license or other licenses/certifications, and the inability to obtain and maintain the required clearance, license or certification may affect an employee's ability to maintain employment. JT4 develops and maintains realistic, integrated test and training environments and prepares our nation's war-fighting aircraft, weapons systems, and aircrews for today's missions and tomorrow's global challenges.
JT4 LLC
Las Vegas, NV
Some jobs may require a candidate to be eligible for a government security clearance, state-issued driver's license or other licenses / certification and the inability to obtain and maintain the required clearance, license or certification may affect an employee's ability to maintain employment. JT4 develops and maintains realistic, integrated test and training environments and prepares our nation's war-fighting aircraft, weapons systems, and aircrews for today's missions and tomorrow's global challenges.
Medical City Frisco
Frisco, TX
Additional options for dental and vision benefits, life and disability coverage, flexible spending accounts, supplemental health protection plans (accident, critical illness, hospital indemnity), auto and home insurance, identity theft protection, legal counseling, long-term care coverage, moving assistance, pet insurance and more. Medical Laboratory Scientist, or Certified Medical Lab, or Certified Lab Technologist, or Clinical Laboratory Scientist, or Medical Lab Scientist, or American Medical Technologist is required.
Spectraforce Technologies Inc
$71900 - $115440
Pleasanton, CA
Position Summary : The Scientist II will perform hands-on molecular laboratory work to support the design, optimization, and development of qPCR and digital PCR (dPCR) assays for the organization’s advanced molecular platforms. Working Conditions & Physical Demands : The following reflect the physical and environmental expectations of this role: • Ability to stand or sit for extended periods while performing laboratory duties.
JT4 LLC
Edwards Air Force Base, CA
Associates degree in Computer Programming or a related field; or equivalent technical training from an accredited academic institution, completion of a recognized certification program, or equivalent experience and demonstrated skills, knowledge, and technical competence in computer programming. Some jobs may require a candidate to be eligible for a government security clearance, state-issued driver's license or other licenses / certifications and the inability to obtain and maintain the required clearance, license or certification may affect an employee's ability to maintain employment.
Hub Technology Group
Albany, NY
Senior Project Manager will work across environmental and industrial subject areas and support planning and coordinating environmental and regulatory review and permitting for projects.support our growing ecological sciences practice in New York. Project Managers should have experience with environmental permitting, project management and general environmental experience for solar, water and wind licensing and permitting for traditional energy sectors.
Charter Steel
Cleveland, OH
Maintain knowledge of current regulations and analyze proposed regulations affecting the business to address risks to the business, informing leadership, and implementing appropriate controls to sustain compliance. Partner with operations to support project work and problem solve operational environmental issues, providing guidance to optimize and strengthen compliance systems.
The LiRo Group
Albany, NY
Work experience "having a substantial relationship to environmental analysis" meaning that at least 50% of the time is spent preparing and/or reviewing NYS SEQR environmental impact statements; providing consultation on NYS and federal environmental impact laws, rules and regulations; or conducting office evaluations and field investigations in conjunction with such multi-disciplinary environmental regulatory programs as water quality, wetlands, air quality, solid and hazardous waste management, and mining. Recently, Global Infrastructure Solutions Inc. (GISI), the parent company of The LiRo Group and Hill International, Inc. consolidated a portion of the highly experienced staff of both LiRo and Hill in the Northeast to create a larger, more efficient, and cost-effective team to serve clients.
The LiRo Group
Albany, NY
Work experience "having a substantial relationship to environmental analysis" meaning that at least 50% of the time is spent preparing and/or reviewing NYS SEQR environmental impact statements; providing consultation on NYS and federal environmental impact laws, rules and regulations; or conducting office evaluations and field investigations in conjunction with such multi-disciplinary environmental regulatory programs as water quality, wetlands, air quality, solid and hazardous waste management, and mining. Recently, Global Infrastructure Solutions Inc. (GISI), the parent company of The LiRo Group and Hill International, Inc. consolidated a portion of the highly experienced staff of both LiRo and Hill in the Northeast to create a larger, more efficient, and cost-effective team to serve clients.
Southwest Research Institute
San Antonio, TX
Using a knowledge of chemistry and physics, assess projects to ensure mitigation of hazardous conditions, evaluate chemicals involved in processes to confirm that materials being used are compatible and personnel are protected from any emissions or exposures. Requirements: Requires a Bachelors degree in Occupational Health and Safety, Environmental Science, Industrial Hygiene, Environmental/Industrial/Civil Engineering, Chemistry, Biology, Public Health, or related degree with relevant work experience.
US Tech Solutions, Inc.
$32 - $35
Sunnyvale, CA
US Tech Solutions is a global staff augmentation firm providing a wide range of talent on-demand and total workforce solutions. Use manufacturing protocols to accurately synthesize raw and functionalized resins for column production for HPLC.
Apex Companies LLC
$45000 - $55000
Seattle, WA
This posting is forSeattle, WAbut we are hiring nationwide across these locations:Boston, Newark, Philadelphia, Raleigh, Jackson, Atlanta, Tampa, Nashville, Cleveland, Cincinnati, Louisville, Chicago, Minneapolis, Dallas, Kansas City, Denver, Pocatello, Phoenix, Portland, Seattle, Los Angeles, San Francisco/Bay Area, and Sacramento. Powered by record sales, extraordinary client retention, strategic acquisitions, and an entrepreneurial spirit, Apex Companies is one of the fastest growing engineering and environmental consulting firms in the US.We were recently recognized by the Zweig Group as one of the fastest growing firms in the AEC industry.
Cherokee Federal
$50000 - $60000
Columbia, MO
Project Support: Support planned projects assessing the effects of contaminants (e.g., PFAS) in the environment by contributing to data analyses and ensuring data adheres to quality control and quality assurance plans. Data Management: Organize and manage data effectively, using appropriate software and databases to maintain clear records and facilitate easy retrieval for analysis and reporting (e.g., MassLynx, R, excel).
C.T. Male Associates
$68000 - $90000
Latham, NY
This role will primarily perform office work necessary to complete environmental site assessments, geologic and hydrogeologic investigations, site remediation, field sampling, environmental permits, and other environmental projects. Conduct projects including aquifer testing and evaluation; drilling oversight and soil/rock logging; supply well construction observation; sampling of environmental media; soil boring and monitoring well installation observation; and well development, purging, and sampling.
Foundation for the NIH
$185000 - $225000
North Bethesda, MD
The Director will work closely with biopharmaceutical, chemical, agrichemical, and comestics companies, regulatory agencies, academic investigators, and patient-focused organizations to accelerate the adoption of scientifically robust, fit-for-purpose models that improve predictive safety assessment and drug development and reduce reliance on traditional animal testing. The Director, New Approach Methodologies (NAMs) for toxicology and drug development, will lead the strategy, development, and execution of multi-sector scientific partnerships to advance, validate, and qualify innovative alternative models for drug development and human safety toxicity testing.
Pace Analytical Life Sciences
$65000 - $75000
Salem, NH
See Pace Analytical Privacy Policy at https://www.pacelabs.com/privacy-policy/ and SonicJobs Privacy Policy at https://www.sonicjobs.com/us/privacy-policy and Terms of Use at https://www.sonicjobs.com/us/terms-conditions. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, recall, transfer, leaves of absence, compensation and training.
MOFFATT & NICHOL
$89000 - $105000
Federal Way, WA
The firm provides clients worldwide with customized service and a level of excellence that have become the firm's hallmark in several primary practice areas - ports and harbors; coastal, environmental and water resources; urban waterfronts and marinas; transportation, bridges and rail; inspection and rehabilitation; and energy. This environmental planner will play a vital role in conducting tasks that could include biological and/or environmental assessments, environmental review, permitting, and integrating environmental principles into planning and development processes to ensure regulatory compliance for M&N projects while enhancing community and resiliency.
The Corning Museum of Glass
$18.25 - $22.25
Corning, NY
Participate in Hot Glass Programs and Events team meetings as requiredActively participate in production efforts and income-generating initiatives like MADE Independently produce Bologna bottles for Glass Breaking Demo. 50,000+ objects representing more than 3,500 years of history are included in the Museum’s collection—ranging from a portrait of an ancient Egyptian pharaoh to a 200-inch telescope lens to contemporary sculpture.
Johns Hopkins Applied Physics Laboratory (APL)
$100000 - $245000
Laurel, MD
By leveraging Directed Energy Deposition (DED) and novel alloy design, you will create components that are lighter, stronger, and more heat-resistant than legacy hardware, directly impacting the kinematic reach and lethality of US defense systems. With a focus on advanced propulsion, next generation interceptors and structural integrity, we are seeking a subject matter expert in Metallurgy and Additive Manufacturing (AM) to revolutionize the production of aerospace propulsion and structural systems.
EA Engineering, Science, and Technology, Inc., PBC
$135000 - $175000
Seattle, WA
This is a high-impact role supporting one of EA's largest regional clients across multiple project sites and states in the Pacific Northwest. Factors considered when making an offer include job responsibilities, education, experience, knowledge, skills, abilities, internal equity, alignment with market data, and compliance with federal and state laws.
Lancesoft Inc
$23 - $26
Kansas City, MO
Associate Scientist II under general supervision, performs work that is varied and that may be somewhat difficult in character, but usually involves limited responsibility. Performs parallel review of documentation and may become qualified to perform technical review of documents for accuracy, thoroughness and regulatory compliance.
GeoEngineers, Inc.
$63000 - $99000
Seattle, WA
As a Staff Environmental Engineer/Scientist, you will be responsible for performing field work to collect environmental data (soil, sediment, groundwater and vapor), performing oversight of cleanup construction, preparing field reports and logs, evaluating and interpreting environmental data, and assisting project managers in preparation of cleanup and design documents including work plans, reports, plans and specifications and engineers estimates. Field explorations may include drilling and test pitting to collect soil samples, sediment grab sampling and coring, monitoring well installation and collection of samples from varying environmental media (groundwater, wastewater, stormwater, etc.).
JT4 LLC
Edwards Air Force Base, CA
Some jobs may require a candidate to be eligible for a government security clearance, state-issued driver's license or other licenses/certifications, and the inability to obtain and maintain the required clearance, license or certification may affect an employee's ability to maintain employment. This knowledge and these skills may be obtained by graduation from a two to four-year technical institute or college, or possess equivalent formal technical training or military equivalent and two or more years of experience in a directly related technical working environment.
Puget Sound Energy, Inc
Clyde Hill, WA
Implement the waste module of the software selected to support PSE's EMS, including mapping existing waste management work processes and waste reporting processes, understanding applicable regulatory, permitting, recordkeeping, and reporting requirements, learning company requirements, and optimizing work practices, using the waste module to support them. The Senior Environmental Scientist will represent the waste team on a larger Environmental Services project to implement software to support PSE's environmental management system (EMS), starting with implementation of a waste compliance module.
MacKay Sposito
$125000 - $147000
Vancouver, WA
Manage and prepare technical reports for a variety of natural resource requirements, including Biological Assessments, Critical Areas Reports, Shoreline Permits, 404/401 applications, NEPA/SEPA documents, etc. Lead annual and long-term planning strategy development and implementation while mentoring business development and marketing seller/doer skills in junior staff.
Department of Ecology
$75108 - $100980
Lacey, WA
Ecology employees may be eligible for the following: Medical/Dental/Vision for employee & dependent(s), Public Employees Retirement System (PERS), Vacation, Sick, and other Leave, 11 Paid Holidays per year, Public Service Loan Forgiveness, Tuition Waiver, Long Term Disability & Life Insurance, Deferred Compensation Programs, Dependent Care Assistance Program (DCAP), Flexible Spending Arrangement (FSA), Employee Assistance Program, Commute Trip Reduction Incentives, Combined Fund Drive, SmartHealth *Click here for more information. Support the overall management of the Deschutes Estuary Restoration Project, and lead the following areas of the project: Environmental Permitting and Design Coordination: Serve as the lead planner for environmental permitting for the Deschutes Estuary Restoration Project, coordinating closely with the Southwest Region Planner and project leadership to align permitting, design, and implementation schedules.
ANCHOR QEA, LLC
Seattle, WA
Apply online through Anchor QEA's Open Positions page athttps://www.anchorqea.com/careers/careers-open-positions/.Veterans are encouraged to apply. Current undergraduate or graduate students majoring in a field related to one of our areas of expertise: Environmental Sciences(chemistry, biology, ecology, marine science, etc.).
ANCHOR QEA, LLC
Seattle, WA
Current undergraduate or graduate students majoring in a field related to one of our areas of expertise: Engineering (coastal, geotechnical, environmental, civil, water resources, etc.). Apply online through Anchor QEA's Open Positions page athttps://www.anchorqea.com/careers/careers-open-positions/.Veterans are encouraged to apply.
Department of Ecology
$3132 - $4119
Lacey, WA
Ecology employees may be eligible for the following: Medical/Dental/Vision for employee & dependent(s), Public Employees Retirement System (PERS), Vacation, Sick, and other Leave*, 11 Paid Holidays per year*, Public Service Loan Forgiveness, Tuition Waiver, Long Term Disability & Life Insurance, Deferred Compensation Programs, Dependent Care Assistance Program (DCAP), Flexible Spending Arrangement (FSA), Employee Assistance Program, Commute Trip Reduction Incentives(Download PDF reader), Combined Fund Drive, SmartHealth *Click here for more information . Ecology seeks diverse applicants: We view diversity, equity, inclusion, and respect through a broad lens including race, ethnicity, class, age, religion, sexual orientation, gender identity, immigration status, military background, language, education, life experience, physical disability, neurodiversity, and intersectional identities.
LimnoTech
Ann Arbor, MI
LimnoTech has an opportunity for an early career environmental scientist or engineer to help meet ongoing and expanding project needs focused primarily on environmental monitoring and the investigation of surface water, soil, groundwater, and sediment quality. The scientist or engineer hired will support a variety of projects, including, but not limited to, investigation of soil and groundwater contamination, vapor intrusion investigations, surface water sampling and monitoring, and sediment coring.
GEO SYNTEC CONSULTANTS
Seattle, WA
Building a portfolio of clients by obtaining repeat business from existing clients and winning new clients; Fostering trust-based relationships with clients, regulatory personnel, and other project stakeholders; Drive personal, company, and rental vehicles to client or company project or office sites, and other business locations, as needed. Our Environmental Practice tackles challenges on a variety of complex environmental projects throughout the Pacific Northwest including environmental site assessments, remedial investigations/feasibility studies, property cleanup and urban redevelopments, remedial design engineering, cost recovery/allocation/mediation support, and landfill system monitoring and optimization.