HAZARD ASSESSMENT

One of the first things facilities subject to the chemical accident prevention program are required to do is to conduct a hazard assessment.  The primary purpose of the hazard assessment is to analyze the potential and historic danger posed by processes containing chemicals regulated under the program to the community including risk to, residents, schools, hospitals, recreational facilities and other public and environmental receptors.

There are two main elements that comprise the hazard assessment.  The first is called an off-site consequence analysis (OCA).  The OCA integrates chemical properties and accidental release conditions into an air dispersion model to predict the area potentially affected by a chemical accident.  The predicted area within the OCA is called a “hazard zone”.  The area within the hazard zone is an estimation of potential harm to people and the environment beyond a facility’s property that can result from the modeled chemical accident.

There are two types of OCA that must be considered.  The first is called a worst-case scenario.  The worst-case scenario is based on conservative assumptions.  It is meant to represent a severe accident that is highly unlikely to occur.  The purpose of the Worst-case scenario is to determine the level of regulatory oversight, called prevention program levels.  It is also used as bases for mitigation efforts to reduce or eliminate the hazard zones when possible.

The second type of OCA is called an alternative release scenario.  The alternative release scenario is based on more realistic assumptions.  It represents a less severe but more likely accident.  The purpose of the alternative release scenario is to create an emergency response planning tool for training and exercises.

The other element required by the hazard assessment is a review of previous accidents over the last five years.  The five year accident history review is used to assess the impacts of previous accidents that have occurred at the facility.

TOOLS AND GUIDELINE

Risk Management Program Guidance for Offsite Consequence Analysis (March 2009)

http://www.epa.gov/emergencies/docs/chem/oca-chps.pdf

RMP*Comp is a free program that can be used to complete the OCA analysis.

http://www.epa.gov/emergencies/content/rmp/rmp_comp.htm

Using Cameo tools for RMP

http://response.restoration.noaa.gov/oil-and-chemical-spills/chemical-spills/resources/ask-dr-aloha-rmp-and-epcra-hazard-analyses.html

ACCESS TO INFORMATION

40 CFR part 1400, Distribution of Off-site Consequence Analysis Information

http://www.gpo.gov/fdsys/granule/CFR-2004-title40-vol30/CFR-2004-title40-vol30-part1400/content-detail.html

Federal Reading Rooms

http://www.justice.gov/nsd/foia/foia_library/chemical_hazards.htm