1. Chemical Screening Tool for Exposures and Environmental Releases
ChemSTEER Overview
Chemical Screening Tool for Exposures and Environmental Releases
Office of Pollution Prevention & Toxics
Chemical Engineering Branch
Washington, DC
May 2004
Beta Version 1

2. What does this PC-based software do?
Estimates workplace exposures and releases to a chemical:
in the absence of monitoring data
estimates are screening-level
uses EPA methods and models 2

3. How can it be used? Currently used by EPA for: Other potential uses: 3
Workplace release and exposure estimation for new chemicals submitted for PMN review under TSCA Section 5*
Sustainable Futures Program submissions
Other potential uses:
Fill data gaps in HPV exposure assessments
As an initial Green Engineering design tool
* Note: Of the new chemicals regulated under Section 5, a significant fraction are regulated based on estimated workplace release and exposure 3

4. Exposure Information Flow in New Chemicals Risk Screening
Exposure X Hazard = RISK
Occupational
Environmental
(Aquatic, Terrestrial, Avian)
Non-occupational
(Consumer, General Population)
Releases (Land, Water, Air)
ChemSTEER
EXAMPLE INPUTS:
* Physical / Chemical Properties
* Production volume, Batch Size
* Industry Specific profiles, Generic models, etc.
E-FAST
* Physical /
Chemical Properties
* Stream Flows
* Consumer Profiles 4

5. How can it be used in the P2 Framework?
The MPBPVP Model may be used to estimate a chemical’s vapor pressure and the WSKOW Model may be used to estimate a chemical’s water solubility. Each of these parameters are used in some of the ChemSTEER models.
Vapor pressure
MPBPVP
WSKOW
ChemSTEER
E-FAST
Water solubility
Env. releases
The ChemSTEER environmental release estimates may be used as inputs to the E-FAST Model. 5

6. How does it work?
You “build” your assessment by entering some key inputs:
Data on the chemical to be assessed, including:
Production volume (or assessed volume) (kilograms per year)
Physical/ chemical properties (known or estimated)
Select at least one operation (i.e., workplace); options include:
Pre-defined industry-specific / use-specific operation
User-defined operation 6

7. How does it work? (continued)
You “build” your assessment by entering some key inputs:
Select at least one release source/ exposure activity within each operation
Each source/ activity is associated with default models for calculating releases and worker inhalation and dermal exposures
Enter mass balance and container-related data
Review models and model input data 7

8. Entering General Information
This tab allows you to view and/or enter general information related to the ChemSTEER assessment:
Assessment name
Date of completion
Assessor information
Contact information for the assessment
Report(s) summarizing information received from a contact
General comments related to the assessment 8

9. Entering Chemical Information
This tab allows you to view and/or enter information related to the chemical to be assessed.
The Production Volume (PV) (amount of chemical to be assessed) is an important input parameter – it is used in many mass balance, container-related, release, and exposure calculations.
The physical-chemical property parameters (e.g., vapor pressure, molecular weight) may be needed by some release and/ or exposure models. 9

10. Selecting Operations to be Assessed
An Operation is a workplace or set of “homogeneous” workplaces with essentially the same processes, equipment, chemical throughputs, procedures, and worker populations.
Each of the workplaces within an operation are assumed to have the same releases of and worker exposures to the chemical being assessed.
One or more operations, in which the chemical is manufactured, processed, and/or used, are selected to be included in the chemical assessment.
Some examples of operations are:
Manufacture
Formulation of paint (User-defined Processing)
Formulation of adhesives
Automobile spray coating 10

11. Setting the Operation Relationships
The relationships between multiple operations may be defined in ChemSTEER. A straight-series lifecycle of more than one operation (shown below) is the default relationship configuration.
Manufacture
Paint formulation
Cleaner formulation
Auto Spray Coating
1 0 0 % P V
ChemSTEER allows you to re-define the operation relationships. For example, the above series can be rearranged into a more complex, branched lifecycle of operations as follows:
75% PV
Manufacture
Paint formulation
Cleaner formulation
Auto Spray Coating
25% PV 11

12. Selecting Sources/Activities
For each operation,
At least one release source/ exposure activity must be selected
This selection is critical, as it will determine which default release/exposure models are used for the calculations.
A source/activity is a source of chemical release to the environment and/or an activity that results in a worker exposure to the chemical within an operation. 12

13. Entering Operation Mass Balance Parameters
Mass balance parameters are the set of input values that define each operation and associated chemical throughputs.
ChemSTEER allows you to input the information that is known and will calculate remaining unknown parameters based upon a mass balance of the chemical around the operation.
Consult the Help System to learn more about the logic by which ChemSTEER makes mass balance calculations. 13

14. Entering Operation Container Parameters
Container parameters are the set of input values that define the number of containers that are filled with the chemical, emptied, and/or cleaned during each operation.
As with the mass balance parameters, ChemSTEER allows you to enter information about the containers that is known and will calculate remaining unknown parameters based upon a mass balance.
Consult the Help System to learn more about the logic by which ChemSTEER makes container-related calculations. 14

15. Release Calculations
At least one default release model is associated with each source/ activity within each operation.
The release models are used for calculating the chemical releases to the environment that occur during the activity.
In the screen shown above, the default model for calculating releases from the ‘Loading Liquid Product into Small Containers’ source within the ‘Formulation of Paint’ operation is the EPA/OAQPS AP-42 Loading Model. 15

16. Release Calculations (continued)
Each release model contains the input parameter values that are necessary to perform the calculation by default.
Some values are obtained via previous input or calculations (e.g., mass balance or container parameters) or are pre-programmed defaults.
You may modify any of the model input parameters (provided they are not determined through calculations performed in another input screen). 16

17. Release Calculation Results
Environmental release results include:
Media of release (i.e., air, water, incineration, and/or landfill)
Characterization (e.g., typical, worst case, average, high end)
Number of sites releasing the chemical
Days of release (days per site-year)
Daily release rate (kg chemical per site-day)
Annual release rate (kg chemical per year, all sites combined) 17

18. Worker Exposure Calculations
The exposure models are used for calculating the worker inhalation and dermal exposures to the chemical during the activity.
As with the release sources, each activity resulting in a worker exposure will have associated default inhalation and/or dermal exposure model(s).
In the screen shown above, the default inhalation model for worker exposure to the chemical vapor during the ‘Loading Liquid Product into Small Containers' activity within the ‘Formulation of Paint’ operation is the EPA/OPPT Mass Balance Model. 18

19. Worker Exposure Calculations (continued)
Each exposure model contains the input parameter values that are necessary to perform the calculation by default.
Some values are obtained via previous input or calculations (e.g., container parameters, associated release model calculations) or are pre-programmed defaults.
You may modify any of the model input parameters (provided they are not determined through calculations performed in another input screen). 19

20. Exposure Calculation Results
Worker exposure results include:
Route of exposure (i.e., inhalation or dermal)
Characterization (e.g., typical worst case, average, high end)
Total number of workers exposed
Days per year of exposure
Potential dose rate (mg per day)
Lifetime average daily dose (mg per kg-day)
Average daily dose (mg per kg-day)
Acute potential dose (mg per kg-day) 20

21. Features – User-Friendly Design
ChemSTEER is designed such that new, as well as experienced users can use the software to perform screening-level estimates:
ChemSTEER steps you through the process of creating an assessment scenario
Every screen contains instructions of what inputs you must enter to proceed
All default models are designed to be transparent (i.e., all assumptions and values are documented)
ChemSTEER contains an extensive Help System that documents the bases for every model and every default value. The Help System also contains a library of background documentation. 21

22. Features – Creating Summary Reports; Saving Assessments
You may view and print an EPA-formatted summary report (shown at left). You may also save the report to a destination on your hard drive or external disk - as a text* (.txt) file or various other types of file formats (*only the text file format has been thoroughly tested).
Assessments may be saved as individual records in a database file containing multiple assessments.
Maintaining a database of multiple assessments allows you greater flexibility in organizing collections of assessments. 22

23. What is its status? May 2004 Beta version
Contains primary “broadly applicable” models (e.g., drum loading release and exposure, equipment cleaning, dermal contact, etc.) and industry-specific models
17 release models
17 exposure models
Contains 4 industry-specific operations
two Automotive Spray Painting operations
one Adhesives Formulation operation
one Water-Cooling Tower Additive Use operation 23

24. Summary of New Features
Since the last public release of ChemSTEER in July 2003, the following new functions have been implemented in this version:
Capability of opening/modifying older assessments with new versions of the software
Automatic transfer of contact information to multiple Contact Reports
Operation NAICS code search function
New Recirculating Water-Cooling Tower Additive Use industry-specific operation
Automatic transfer of site information from one operation to another 24

25. Summary of New Features
Container unloading & cleaning sources/activities are automatically added to operations as a pair (one is automatically added when the other is added by the user)
Model status messages on the Releases and Exposures tabs
Ability to run two sets of inputs (or conditions) in a single model to calculate two release or exposure estimates
Releases are no longer combined in ChemSTEER or in the IRER
Each of these new features is described in the ChemSTEER Self-Guided Tutorial, which can be viewed/downloaded from EPA’s web site (see next slide). 25

26. For More Information
Contact information and the most recent version of ChemSTEER are available from the following EPA Internet site:
This web site also contains links to the ChemSTEER Self-Guided Tutorial, as well as to other exposure-related information and models available from EPA. 26