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HAWC is a modular content management system designed to store, display, and synthesize multiple data sources for the purpose of supporting the development of human health and environmental assessments of pollutants. This online application documents the overall workflow of developing an assessment, from literature search and systematic review, to data extraction (human epidemiology, animal bioassay, and in vitro assay), dose-response analysis, and finally evidence synthesis and visualization.

The key organization principle in HAWC is an assessment. An assessment is a project which is owned by a collection of managers, team-members, and reviewers. An assessment team collaborates to load, extract, and visualize data, generally from peer-reviewed publications, for an assessment. HAWC streamlines this process by including opinionated data extraction forms and workflows designed for content extraction using approaches and techniques recommended in systematic review literature. After data extraction or upload in HAWC, custom interactive visualizations and tabular exports can be created which can inform risk assessments and allow users to dive into the details for key decisions made. Generally, assessments are private to team members during the development of the assessment but can be made public when the assessment is under review or is finalized. We generally recommend making an assessment public and including as supplemental materials in your finalized assessment.

For more details, see the paper:

Shapiro AJ, Antoni S, Guyton KZ, Lunn RM, Loomis D, Rusyn I, Jahnke GD, Schwingl PJ, Mehta SS, Addington J, Guha N. Software Tools to Facilitate Systematic Review Used for Cancer Hazard Identification. Environ Health Perspect. 2018 Oct;126(10):104501. DOI: 10.1289/EHP4224

Should you find HAWC useful for your research, this is our preferred citation for the software.

More technical documentation is available at readthedocs.io. This documentation also includes detailed notes on statistical methods used. HAWC is open-source software under the permissive MIT license. It is free to download, edit, and modify the source code.

Data Status

The HAWC database changes daily as users add content to ongoing assessments. Below is a list of the current counts for different types of data captured in the database. In most cases, these data are available in assessments are currently under development, and thus may not yet be publicly available:

  • General Information
    • Registered HAWC users: 1,947
    • Assessments (public and private): 1,243
  • Literature Tagging
    • References imported or found from searches: 743,959
    • Number of tags applied to references: 388,603
    • Tagged references: 291,549 (39%)
  • Risk of Bias and Study Evaluation
    • Studies with data extracted: 7,518
    • Assessments with studies: 365 (29%)
    • Risk of bias scores: 98,191
    • Studies with risk of bias: 4,151 (55%)
  • Data Extraction
    • Animal bioassay endpoints: 19,411
    • Animal bioassay endpoints with data extracted: 18,039 (93%)
    • Epidemiology outcomes: 5,174
    • Epidemiology results with data: 8,382 (100%)
    • In vitro endpoints: 3,502
    • In vitro endpoints with data: 3,170 (91%)
  • Data Synthesis and Visualization
    • Visualizations: 1,816
    • Assessments with visuals: 151 (12%)

Last updated: April 24, 2024, 6:50 p.m.


Date Milestone
Apr 2024 Quarterly updates released (2024-Q1).
Feb 2024 Quarterly updates released (2023-Q4).
Oct 2023 Quarterly updates released (2023-Q3).
Aug 2023 Quarterly updates released (2023-Q2).
Apr 2023 Quarterly updates released (2023-Q1).
Jan 2023 Quarterly updates released (2022-Q4).
Oct 2022 Quarterly updates released (2022-Q3).
Jul 2022 Quarterly updates released (2022-Q2).
Apr 2022 Quarterly updates released (2022-Q1).
Feb 2022 Quarterly updates released (2021-Q4).
Sep 2021 Quarterly updates released (2021-Q3).
Jun 2021 Quarterly updates released (2021-Q2).
Mar 2021 Quarterly updates released (2021-Q1).
Dec 2020 Quarterly updates released (2020-Q4).
Sep 2020 Quarterly updates released (2020-Q3).
Jun 2020 Quarterly updates released (2020-Q2).
Mar 2020 Quarterly updates released (2020-Q1).
Aug 2018 EPA accepted the design and integrated an early version of HAWC. HAWC is primarily supported by the US EPA.
Jan 2015 The development of HAWC was supported and initially used for assessments at the NIH/NIEHS/NTP in the Office of Health Assessment and Translation (OHAT).
Sep 2012 The initial prototyping of HAWC began per a research thesis at University of North Carolina, Chapel Hill.


HAWC has been developed over many years and has been supported by multiple organizations. Currently, it is primarily supported by the US Environmental Protection Agency. This application was originally a master’s thesis of Andy Shapiro at the University of North Carolina at Chapel Hill under the supervision of Dr. Ivan Rusyn. This project has been supported, in part, by funding from the following sources:

  • US Environmental Protection Agency (EPA)
  • National Toxicology Program (NIH/NIEHS/NTP)
  • Texas A&M University
  • EPA grants STAR RD83574701 and STAR RD83516601
  • NIH grant P42 ES005948
  • The International Agency for Research on Cancer (WHO/IARC)

The contents of HAWC are solely the responsibility of the users and developers, and do not necessarily represent the official views of EPA, NIH, Texas A&M University, or WHO. Further, EPA, NIH, Texas A&M University, and WHO do not endorse the purchase or use of any commercial or open-source products or services that were used in the development of HAWC.