Citizen’s Challenge to Orcem/VMT’s Air Quality Assessment on Chimney

by | Aug 13, 2018 | 0 comments

By Jay Gunkelman


I have challenged the scientific validity of the Health Risk Assessment in Appendix D-1 of the Orcem/VMT environmental impact report (EIR).

My assessment is that the Health Risk Assessment (HRA) and the modeling used by Orcem/VMT to measure particulate matter emissions is flawed.  I believe:

  • Orcem/VMT used the wrong guidelines for measuring the particulate matter which would emit from its smokestack.
  • Orcem/VMT did not accurately measure the impacts of the particulate matter on the surrounding neighborhoods.
  • Orcem/VMT selected the wrong modeling method for an urban area.
  • Orcem submitted expired samples to the Lab which could not be tested properly.
  • Orcem/VMT did not measure the particulate matter from material handling, truck, train & ship emissions during inversion conditions.
  • Orcem/VMT used inaccurate temperature data to measure the stack emissions.


Their science in this EIR is flawed and the details are outlined in the following section… with a somewhat irreverent mnemonic being presented at the end:


The modeling option to use buoyancy to float small particles is not recommended, though it was used.  The sizing level used to float particles was set arbitrarily at just under 2 microns of particle size.  This is just below the 2.5-micron threshold regulators would be concerned with, but considerably larger than the actual size where particles ‘float’.  Particles actually do float with air turbulence at 0.2 microns… a full order of magnitude smaller.

This might sound like just a technical issue without any real effect, except the particles at 1 micron contain over 90% of the heavy metal toxicity.  They float these particles and over 90% of their toxicity out of the modeling, making the outcome much cleaner on paper than it would be in reality.  The real science of particle size floatation is seen below and in the table the 0.001 particle size is one micron.


The applicant used RURAL modeling methods which are an option… however the conditions under which this can be selected are either based on population or Zoning, and reflect the area encompassed by a 3-kilometer circle around the proposed plant site.  The 3 KM radius must have over 50% rural zoning to select the rural modeling alternative, and this is clearly not the case even with the most cursory review of the project site map.  We are really supposed to be modeled as URBAN.


The Hexavalent chromium sample submitted by Orcem could not be tested properly.  Hexavalent chromium degrades and the sample submitted fell outside the lab standards which require the analysis to be done within 15 minutes, or that the sample be stabilized to a neutral level of alkalinity/acidity, to avoid valence changes.  The testing lab highlighted this violation of lab standards.  The samples should never have been run outside lab standards.


The HRA only modeled the stack… no fugitive emissions from material handling, no trains, no trucks or any other sources were included.  SUPPRESSION of sources in the modeling of inversion meteorology is not proper modeling of these conditions when idling trucks and ships and train engines would add substantially to the background exposure actually experienced, if not modeled.


In my review I saw a stack temperatures at over 300 degrees, which at the time stuck me as just bad engineering.  Losing excess heat is an expensive loss of the funds used to make heat if you do not recapture it.  Most stacks operate in the 190 degree range, to not lose too much heat, so a stack exit temperature well over 300 degrees looked like a design issue… until I thought of it as a way to gain more “loft”… an additional 100 degrees of HEAT gives substantial added loft.  This 300 plus degree stack exit temperature which was listed at 200 plus degrees everywhere else in the EIR… making this a suspicious “change”.


Now for the mnemonic acronym:

Buoyancy of particles that do not float

Urban modeling

Length of time Hexavalent chromium was held was excessive

Suppression of source data in inversions


B.U.L.S.HEAT is exactly what the particulate dispersion model and HRA were built upon.


Jay Gunkelman