“Approach for Estimating Exposures and 

Incremental Health Effects from Lead 

due to Renovation, Repair, and Painting 

Activities in Public and Commercial 

Buildings” 

Reference Guide for Running Leggett 

Model Version 5

November 2014

EPA Office of Pollution Prevention and Toxics

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

Assistance and support provided by ICF International under Contract number EP-C-14-001
EPA OPPT 2 November 2014

Running Leggett Model Version 5

1. Extracting and Running the Model

The “Approach for Estimating Exposures and Incremental Health Effects from Lead due to Renovation, Repair, 

and Painting Activities in Public and Commercial Buildings” (Approach) uses a new Leggett model, version 5. 

This document provides information about how to extract and run the Leggett model.

The model and all supporting files are posted in a zip file which can be located at the following website. 

http://www2.epa.gov/lead/approach-estimating-exposures-and-incremental-health-effects-lead-duerenovation-repair-and

The model itself is a 32-bit executable that will work on either 32-bit or 64-bit Windows machines. The model 

(ICRPv005d.exe) pulls inputs from a file called “POUNDS.DAT”, and outputs are in a file named “TEMP.DAT”. 

The code itself is also provided for reference (“ICRPv005d.FOR”). It can only be changed if the user has a 

compiler they can use to recompile the code.

To run the model, double clicking the ICRPv005d.exe file will run the model using whatever inputs are in the 

POUNDS.DAT file in the same directory. The outputs are then in the TEMP.DAT file. 

If you receive an error, it is best to open up a command window in windows by going to All Programs -> 

Accessories -> Command Prompt. From there, navigate to the folder where the model is saved and then type 

“ICRPv005d.exe” at the command line. The errors will then be listed in the command window.

To facilitate building input files and plotting the results, EPA has also developed an “Excel Wrapper” tool. This 

tool allows the user to specify a time series of exposure values in Excel, build the Leggett input file, run the 

model, and import the results. This tool is called “Leggett_Tool.xlsx” and accompanies the Leggett model in the 

zip file. A “Readme” tab in the Excel file gives instructions on using the tool. Please note, to use the tool, the 

user needs to understand how the Leggett model handles time steps and run length in the input file (see 

“Exposure Inputs” section below) and how variables are chosen for the output file (see “Output File” section 

below).

The remainder of the document discusses the structure of the input and output files so that the user can 

manipulate and analyze these at-will.

2. The Input File

The input file is organized as a series of line inputs that are numbered. In general, there are two types of 

inputs:

1) Those affecting the timing and nature of exposure (Inputs 1-12) and

2) Those affecting the internal biokinetics (Inputs 13-53).

The exposure inputs (1) were changed for each simulation to match the scenario being modeled. The 

biokinetic inputs (2) were adjusted during the model evaluation stage but were not changed during the Monte 
EPA OPPT 3 October 2, 2014

Carlo modeling. This reference guide covers the exposure inputs in greater detail and provides an overview of 

the structure of the biokinetic inputs.

Exposure Inputs

The exposure inputs cover the timing of exposure and can be changed to model a wide variety of exposure 

scenarios. The table below provides a description of the inputs as well as an example. In the simulations 

performed in the Monte Carlo model and for model calibration, the background intake rates were 

implemented as a “direct to blood” intake while the renovation-related intakes were inhalation and/or 

ingestion.

Table 1. A list of the Exposure Inputs with Description

# Example Values Model Description Additional Description

1 0.0 

Template with 8 time periods and revised 

bone metabolism 3/15/2002 

The value corresponds to the starting age in the 

simulation.

2 1,0,3650,1569.5 

2 - See lines 60-64 for measured values and 

scale factor; NDELT,DELT0,NCYCLE,ENDDAY

These provide the time steps for the model.

NDELT: The number of times the time step length 

will change during the simulation

NDELT0: The time step length in days *if* it 

doesn’t change during the simulation (i.e., NDELT = 

1)

NCYCLE: The number of time steps in the 

simulation

ENDDAY: The final day in the simulation.

3 0.5

3 DELTi; CALCULATIONS FIRST BASED ON 

STEP LENGTHS DELT1, THEN DELT2, ETC

DELTi: The time step lengths in days for each time 

step, if NDELT is greater than 1.

4 3650

4 ICYCi; USE TIME STEP DELT1 UP TO STEP 

ICYC1, DELT2 UP TO ICYC2, ETC

ICYCi: The day when the time step length changes, 

if NDELT is greater than 1.

5 2

5 WRITE TO file and SCREEN ONLY ON 

THESE STEPS (E.G., EVERY 100TH TIME STEP)

How many times the output is saved. The model is 

run every time step, but you can elect to save the 

output only every few time steps.

6 21,32,33,22,23 

6 FIVE SELECTED OUTPUTS 21,1,2,29,22-

21,10,7,8,9-21,4,5,6,13-21,11,12,14,13-

15,16,17,18,19 

The outputs you want to save in the output file. 

See Table 2 for a list of the outputs available. 

7 3,2,0 

7 MODE OF INTAKE; SWITCH FOR 

ACUTE/CHRONIC; SWITCH FOR MANUAL 

INPUT (1)

Mode of intake: 0 = direct to blood only; 1 = 

inhalation only; 2 = ingestion only; 3 = all routes

Switch for Acute/Chronic: Leave at 2 for chronic

Switch for Manual Input: 0 for no manual input

8 23

8 NCHRON, TIME STEPS IN CHRONIC 

INTAKE FUNCTION (UP TO 50)

The number of different exposure values across 

the length of the simulation.
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# Example Values Model Description Additional Description

9

7,14,21,28,35,42,49,56,63,

70,84,98,112,126,140,154,

168,182,196,210,224,238,1

820 

9 ENDPT, ENDPOINTS OF THE CHRONIC 

INTAKE TIME STEPS

The day when the intake values change from one 

to the next (number of values must equal 

NCHRON).

10

5.,5.,5.,5.,5.,5.,5.,5.,5.,5.,5.,

5.,5.,5.,5.,5.,5.,5.,5.,5.,5.,5.,

5. 

10 UP TO 50 CHRONIC INTAKE RATES 

DIRECTLY TO BLD ON STEPS

The intake rates corresponding to exposure 

directly to blood (number of values must equal 

NCHRON).

11

2.0,0.0,0.0,0.0,0.0,0.0,0.0,0

.0,0.0,0.0,0.0,0.0,0.0,0.0,0.

0,0.0,0.0,0.0,0.0,0.0,0.0,0.0

,0.0 

11 UP TO 50 CHRONIC LUNG DEPOSITION 

RATES (PER DAY)

The inhalation intake rates (number of values must 

equal NCHRON).

12

2.0,2.0,2.0,2.0,2.0,0.0,0.0,0

.0,0.0,0.0,0.0,0.0,0.0,0.0,0.

0,0.0,0.0,0.0,0.0,0.0,0.0,0.0

,0.0 

12 UP TO 50 CHRONIC INGESTION INTAKE 

RATES (PER DAY)

The ingestion intake rates (number of values must 

equal NCHRON).

The available outputs are number-coded and up to five can be selected (input line 6). Table 2 provides a key of 

the available outputs.

Table 2. Available Output Variables

# Output Name Output Description Units

1 YPLAS Mass of lead in plasma g

2 YRBC Mass of lead in red blood cells g

3 YBLUD Mass of lead in blood g

4 YSKEL Mass of lead in skeleton g

5 YCORT Mass of lead in cortical bone g

6 YTRAB Mass of lead in trabecular bone g

7 YLIVR Mass of lead in liver g

8 YKDNE Mass of lead in kidney g

9 YSOFT Mass of lead in soft tissue g

10 YBRAN Mass of lead in brain g

11 YURIN Mass of lead in urine g

12 YFECE Mass of lead in feces g

13 TBODY2 Total mass of lead in body g

14 TOTEXC Total mass of lead excreted g

15 BONFRC Fraction of lead in bone none

16 BRNFRC Fraction of lead in brain none

17 HEPFRC Fraction of lead in liver none

18 BLDFRC Fraction of lead in blood none

19 RENFRC Fraction of lead in kidney none
EPA OPPT 5 October 2, 2014

# Output Name Output Description Units

20 OTHFRC Fraction of lead in other tissues none

21 BLCONC Blood lead concentration g/dL

22 RBCONC Red blood cell lead concentration g/dL

23 RENCON Kidney lead concentration g/g

24 CRTCON Cortical bone lead concentration g/g

25 TRBCON Trabecular bone lead concentration g/g

26 ASHCON Ash bone lead concentration g/g

27 CLEAR Total amount of plasma lead cleared via urine g

28 BCLEAR Total amount of blood lead cleared via urine g

29 PCENT Fraction of blood lead that is in plasma none

30 YLUNG Mass of lead in the lung g

31 none Fraction of blood lead cleared none

32 CRTCONBM Cortical bone mineral density lead concentration g/g

33 TRBCONBM Trabecular bone mineral density lead concentration g/g

34 UPTAKEGI Uptake in the GI track g

35 UPTAKERI Uptake via inhalation g

36 UPTAKE Total uptake g

Biokinetic Inputs

The biokinetic inputs make up the rest of the inputs in the model. These inputs represent the parameters 

revisited in spring 2014 and updated to form version 5 of the model. In many cases, the new values appear as 

inputs and can be adjusted by the user. In a few cases, the parameter went from being age-independent to 

age-dependent. For those, the values in the input file are dummy values and the values are hard coded in the 

code. These cannot be changed unless the user can then recompile the code and generate a new executable 

file. These inputs include inputs 47 and 51 (deposition fraction in red blood cells and amount of red blood cells 

and plasma in an adult male), as noted in the input file.

The biokinetic inputs are set up to change at defined ages. In the current input file and model, there are 14 

ages where the inputs can change:

0.,0.274,1.,5.,10.,15.,18.,24.,30.,40.,45.,55.,65., and 75. years old.

The remaining inputs then have values for each of these age groups. For example, a line such as:

8*1.0, 6*0.8

implies “use 1.0 for the first eight age ranges and 0.8 for the last six age ranges”. The user can change the 

values for any or all age groups in the input file.
EPA OPPT 6 October 2, 2014

The model also contains a switch for whether to use the linear or nonlinear RBC equation. This occurs on line 

17 in the input file. The first parameter is the switch (0 = linear, 1 = nonlinear) and the other three parameters 

are the nonlinear equation parameters. 

3. The Output File

The output file is called “TEMP.dat” and will appear in the same folder as the input file after the model 

successfully runs. Always check the date stamp of the output file after running the model to make sure the file 

updated successfully; otherwise, the model likely encountered an error. The output file does not have headers, 

so it is important to understand what is in each column:

Column Variable

1 The time in the simulation in years.

2 The total mass of lead in the body in g. 

3 The data corresponding to the first variable chosen on input line 6 (blood lead in the example 

input file).

4 The data corresponding to the second variable chosen on input line 6 (cortical bone density 

concentration in the example input file).

5 The data corresponding to the third variable chosen on input line 6 (trabecular bone density 

concentration in the example input file).

6 The data corresponding to the fourth variable chosen on input line 6 (red blood cell 

concentration in the example input file).

7 The data corresponding to the fifth variable chosen on input line 6 (kidney concentration in 

the example input file).

The data can be imported into Excel and plotted using Excel’s Data -> Get External Data -> From Text 

functionality or you can use the Leggett_Tool.xslx tool to import the data.

4. The Estimation of the Background Intake Values

The final set of files in the zip file package are the Excel files used to estimate the background intake rates for a 

person born in each year that best match the available NHANES data for that age group, as described in the 

Approach Appendices. Six different age ranges were defined, and starting estimates for the background lead 

intake were derived by assuming 1) the earliest exposure was 100 ug/day and 2) that the ratio of the exposure 

in other years scaled similarly to the ratio between the NHANES mean blood lead values in those years.

In each file, the “RUN” tab contains the inputs. The initial estimate for the age group is shown in Column F, 

while the available NHANES data for different years is shown in Column E, rows 22 and below. The Excel file 

derives the best factor to multiply each of the initial estimates by to best fit the NHANES data, and the rest of 

the tab contains formulas that build the inputs needed for the Leggett input file. Pushing the “RUN” button will 

run the Leggett model multiple times until the mean square error between the predicted and actual mean 
EPA OPPT 7 October 2, 2014

blood leads is minimized. The “MIN” tab shows the mean square error (y-axis) for different multiplicative 

factors (x-axis), and the tool selects the factor where the mean square error is at a minimum. The factor is then 

saved for each age in the age range on the “OUTPUT” tab.

There are seven excel files that characterize background blood lead values by year.

1. Leggett-background-1930-1954-mult.xlsb

2. Leggett-background-1955-1966-mult.xlsb

3. Leggett-background-1967-1976-mult.xlsb

4. Leggett-background-1977-1986-mult.xlsb

5. Leggett-background-1987-1996-mult.xlsb

6. Leggett-background-1996-2011-mult.xlsb

7. Leggett-background-2012-2014-mult.xlsb

To see the full results of this analysis, the “Leggett-background-aggregate.xlsx” file contains all of the NHANES 

data and the blood leads corresponding to the fit intakes. On the “graph” tab, different birth years can be 

selected in cell D2. The graph then shows both the actual NHANES data and the fit blood leads from the 

Leggett model for that birth year.