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Human Health Risk Assessment Protocol 

(HHRAP)for Hazardous Waste Combustion 

Facilities, Final

Human Health Risk Assessment Document | Appendices and Chemical Specific Data | 

Support Materials | Important Notice

This Final HHRAP (EPA520-R-05-006) updates and replaces the 1998 Peer Review Draft 

version of the HHRAP (EPA530-D-98-001). 

Highlights of changes include (but are certainly not limited to): 

We've sculpted the tone of the language throughout the document to make clear that 

the HHRAP is guidance: the various equations, parameter values, and such are our 

recommendations, and not requirements. 

A new method (replacing the Travis & Arms (1988) equations) for estimating 

biotransfer of chemicals into beef and milk cattle.

Clarifications – for example we've further explained (and made consistent) how we 

recommend deriving exposure scenario consumption rates.

Mercury - we've modified our recommended method for estimating mercury loading 

to waterbodies, to address potential mass-balance issues.

Dry Vapor Phase Deposition - We've modified the deposition equations to include 

ISCST3's ability to model dry vapor phase deposition.

New Tox Hierarchies - we've brought the recommended hierarchy of sources for 

chronic tox benchmarks (PDF) (4 pp, 228K) into harmony with Superfund and the rest 

of OSWER. We also added a recommended hierarchy of sources for acute tox 

benchmarks.

The Hazardous Waste Companion Database (ACCESS) (3.3MB) - This database updates 

and replaces the hard-copy listing of chemical-specific parameter values originally 

found in Appendix A of the 1998 HHRAP. We've committed to maintaining the 

currentness of the database, and will post periodic updates on the same web site;

A new central email account, "HHRAPFeedback@epa.gov" for questions/comments.

These are just some of the changes. We encourage you to read and use this resource. If you 

have questions or comments (particularly on how we might make the database more userfriendly), please email us.

Risk assessment is a science used to evaluate the carcinogenic risks and noncarcinogenic 

hazards to human health that are attributable to emissions from hazardous waste combustion 

units. These risk assessments include the evaluation of both direct and indirect risks. There is 

sufficient guidance available regarding the performance of direct inhalation risk assessments. 

On the other hand, indirect risk assessments are newer and more complex. As a result, this 

Wastes - Hazardous Waste - Treatment & Disposal

Human Health Risk Assessment | Combustion | Wastes | US EPA Page 1 of 2

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document describes the evaluation of direct inhalation risk, but primarily focuses on the 

procedures used to estimate risk resulting from indirect pathways. 

Human Health Risk Assessment Document

Download Entire Main Document as a Zipped File (3.2MB)

- Warning: large file size may extend download time

Download By Sections

Appendices and Chemical Specific Data

Download all Appendices as a Zipped File (2.3MB) - Does not include chemical specific 

database

Download Database or Individual Appendices

Support Materials

Methodology for Predicting Cattle Biotransfer Factors

Details the research performed to derive a new method for estimating biotransfer 

factors for beef and milk cattle.

Response to Comments Document

Details the chronology of both public- and external peer-review processes.

Summarizes all public comments and gives our responses

Lists the Charges to the external peer review panel members, their responses, 

and our replies.

Download Both Support Documents as a Zipped File (3.8MB) - Warning: large file size 

may extend download time

Download By Document

Important Notice

How can I get copies of the 

now-superceded Peer 

Review Draft and 

Supporting Documents?

A CD that contains the draft version of the guidance, as 

well as supporting documents such as those related to the 

external peer-review process, can be requested from EPA. 

Send your request to: 

US Environmental Protection Agency 

Office of Solid Waste 

ATTN: HHRAP Support 

Mail Code 5307P 

1200 Pennsylvania Avenue, NW 

Washington, DC 20460

You may also request to have these files emailed to you.

http://www.epa.gov/epawaste/hazard/tsd/td/combust/risk.htm

Last updated on Friday, September 05, 2008

Human Health Risk Assessment | Combustion | Wastes | US EPA Page 2 of 2

http://www.epa.gov/epawaste/hazard/tsd/td/combust/risk.htm 12/6/2011