What's New

September 30, 2008 - EPA is making version 2.1 of BMDS available at this time for public beta testing. Version 2.1 includes a beta (external peer review) version of a new time-dependent toxicodiffusion model for continuous outcomes (Zhu et al., 2005), incorporates graphical plots for the continuous exponential models and allows for the use of individual animal continuous response data. The BMDS toxicodiffusion model was developed by the USEPA National Center for Environmental Assessment (NCEA), through partnerships with the USEPA Neurotoxicology Division (NTD) and the University of South Florida, to characterize toxic effects (e.g., neurotoxicity) that potentially evolve along critical time points. It does this by:

• modeling a dose-response along a time-course of repeated response measures; and
• computing benchmark doses and their confidence limits along the time course.

Documentation for the toxicodiffusion model can also be downloaded. The documentation contains a full description of the model, input requirements, model run options and sample runs.

In addition, EPA is distributing an external review (beta) version of a concentration-time (CxT) model originally programmed by Wil ten Berge. The EPA ten Berge model implements an approach to evaluating the CxT relationships for effects associated with chemical exposures. The EPA's version 1.0 implementation of this model is being distributed along with associated documentation and comments on the model received from external peer reviewers. EPA plans to respond to external review comments and incorporate the ten Berge model into a future version of BMDS.

Finally, EPA has updated this website to offer new online and hands-on training opportunities. The online training tutorial has been updated for the 2.x versions of BMDS. A new web page has been added that details upcoming training opportinities.

July 10, 2008 - BMDS Version 2.0 final is now available. Released on July 10, 2008, it replaces BMDS 1.4.1c as the official BMDS software. BMDS 2.0 is a rewrite of the user interface and risk assessment modeling framework, with a markedly improved functionality and enhanced multi-model processing capabilities. It uses the same underlying source code for the models in BMDS 1.4.1 software, with minor corrections and some important additions. For details on the new user interface, go to the BMDS 2.0 Help menu option in the installed software. BMDS 2.0 also has a new set of quantal models with alternative background (i.e., background additive to dose) and asymptote (i.e., Hill model) parameters, as well as a Beta Exponential set of models.

January 9, 2008 - New online Benchmark Dose Software (BMDS) training is available on the EPA BMDS website (www.epa.gov/ncea/bmds). The training consists of five narrated sets of slides covering (1) Introduction to Benchmark Dose Modeling, (2) Modeling Dichotomous Data, (3) Modeling Dichotomous Cancer Data, (4) Modeling Continuous Data, and (5) Modeling Nested (e.g., Developmental) Data. This course is a narrated, online representation of EPA's 1-day Benchmark Dose Training course with examples using BMDS version 1.4.1c.

November 9, 2007 - BMDS version 1.4.1c is now available. This version updates dichotomous models that were already included on BMDS version 1.4.1b. The updates primarily improve the handling of parameter specifications, particularly in situations where the user may wish to specify the background parameter to be zero.

October 10, 2007 - BMDS 2.0 beta - Build 19 released on October 10, 2007 replaces the first BMDS 2.0 beta release of September 28, 2007 (Build 13). The new Build 19 has important changes and enhancements as a result of additional testing and user exposure and should be downloaded and used instead of Build 13. Enhancements include the ability to better run a number of the BMD models and also added flexibility and fixes for user interface features. Changes include the designation of the new Dichotomous models as Alternate Dichotomous to better reflect their production status. Please refer to the readme.txt file included with the software installation for more details on the BMDS 2.0 beta.

September 28, 2007 - BMDS Version 2.0 beta is now available for inspection and testing (NOTE: this is a beta test version, provided only for your examination and testing - BMDS 1.4.1b should be used for definitive risk assessment calculations). BMDS 2.0 beta employs a new graphical user interface and makes it easy to run a number of models for one data set and compare the results. BMDS 2.0 beta also has a new set of quantal models with alternative background parameters (i.e., background additive to dose). We welcome comments and suggestions on the functioning of the interface and its new features, and on the new models.

August 29, 2007 - BMDS Version 1.4.1b has been added to replace version 1.4.1. This version contains an update to the BMDS help file.

February 5, 2007 - Version 1.4.1 is now available (see BMDS Download Page)! All models have been recompiled to improve speed, stability and compatibility with the latest Windows operating systems. Improvements have been made to the model output format for all models. A Multistage-Cancer model has been added which calculates and reports a cancer slope factor and plots the linear extrapolation from the BMDL to the background response estimate per EPA's 2005 cancer guidelines. Unlike the Multistage model, the Multistage Cancer model does not estimate added risk, nor does it allow beta coefficients to be unrestricted. The Quantal-Quadratic model was removed from Dichotomous model choices (note: the user can still run this model by specifying the power term of the Weibull model to be 2, but this model is not retained in the BMDS dichotomous model listings)

Issues in the continuous models that caused occasional errors in degrees of freedom assignments which impacted continuous model test results have been resolved. Acceptance criteria for Tests 2, 3 and 4 was changed from p>=0.05 to p>=0.1 and default risk type changed to "Std. Dev." for all continuous models to be consistent with EPA's draft BMD technical guidance (EPA, 2000). Issues with the Hill model have been fixed, including memory problems which were causing some operating systems to crash. Parameter standard error estimates and Chi-squared residual calculations in all the continuous models were checked and corrected if in error. Model A3 of the continuous model testing procedures has been modified so that it always uses the user-specified value for the parameter rho, including the constant-variance case where rho = 0. When rho = 0, model A3 is the same as model A1, and it is reported explicitly in the constant-variance runs. As a consequence, all model runs report the entire set of models (A1, A2, A3, R and the fitted model) and all four hypothesis tests.

Issues in the Nested models that caused occasional errors in degrees of freedom assignments have been resolved. Memory problems which were causing problems for some NCTR model runs have been fixed.

May 23, 2003 - Version 1.3.2 of BMDS is now available (see BMDS Download Page)! Version 1.3.2 contains revised polynomial (poly.exe) and nested logistic (nlogist.exe) models that are compatible with Windows 2000. If you are using a Windows 98 or older operating system, you may need to update your msvcrt.dll driver. We suggest that you obtain the latest msvcrt.dll driver from microsoft or download this version of the msvcrt.dll driver and copy it to the c:\windows\system directory of your computer (you may have to exit Windows and do this in DOS mode).

November 13, 2002 - A new polynomial model (Version 2.2) is now available that fixes the previous incompatibility with Windows 2000. Click on this link to get the new poly.exe file. Download it to your main bmds directory (same directory as the bmds.exe file).

January 22, 2002 - Version 1.3.1 of BMDS is now available (see BMDS Download Page)! Version 1.3.1 contains a revised help manual and user interface, including a revision to the interface that allows the Multistage model to calculate BMD and BMDL values for very low (below E-5) benchmark response (BMR) levels.

March 22, 2001 - Version 1.3 of BMDS is now available (see BMDS Download Page)!  This latest version of BMDS, version 1.3, contains new continuous Polynomial (v2.1), Power (v2.1) and Hill (v2.1) models, new dichotomous Multistage (v2.1), Weibull (v2.1) and Gamma (v2.2) models, and an improved user interface.  The new models are more compact and stable (will converge on BMD and BMDL solutions more often).  The user interface upgrades are described in the new help manual (PDF format) for version 1.3 and the readme.txt file that is distributed with the upgrade.

February 20, 2001 - Zip files containing source code for BMDS version 1.2.1 models are now available, along with instructions for compiling them. If you are a programmer and wish to revise the code, please do not distribute the revised code as EPA software. Also, we ask that you let us know about any suggestions you have for possible improvements to the code by emailing us at bmds.ncea@epa.gov. Enjoy!

November 16, 2000 - Discussion Materials for External Peer Review of the Draft Benchmark Dose Technical Guidance Document, Peer Review Documents for Workshop, December 7-8, 2000 

October 25, 2000 - A new version of BMDS, version 1.2.1 is being distributed at this time (see BMDS Download Page).  This version contains new versions of the continuous Polynomial (version 2.1) and Hill (version 2.1) models.  If you do not want to completely reinstall BMDS, you can download the the new model executables (see Latest Versions of BMDS Help and Model Files) and run them separately or under the BMDS version 1.2 interface.  These new versions of the polynomial and Hill models fix problems associated with running the model on Windows NT/2000 operating systems, provide improved model fit for certain unique data sets and improve upon the rate of convergence on a BMD and BMDL.

September 2, 2000 - A new user interface (BMDS0900.exe) was distributed to fix some problems with installation of BMDS on certain Windows 98 configurations.  If you successfully installed BMDS version 1.2 using a previous installation procedure you do not need this upgrade. This upgrade merely simplifies the installation process and corrects some problems that did not allow BMDS to install to certain computer hardware/software configurations. (This version of the software is no longer being made available as there are newer versions now available which fix problems that were being encountered on newer operating systems. See above.)