MEMORANDUM

TO: Tina Ndoh, OAQPS/SPPD – Minerals and Manufacturing Group

FROM: Eastern Research Group, Inc.

DATE: August 14, 2012

SUBJECT: Summary of August 14, 2012 US EPA Meeting with PCS Phosphate

1.0 Introduction

On August 14, 2012, the U.S. Environmental Protection Agency (EPA) met with 

representatives of PCS Phosphate. The purpose of the meeting was to discuss the Risk and 

Technology Review (RTR) for the Phosphate Sector. A brief summary of the visit and discussion 

is outlined in Section 3.0 below.

2.0 Attendees

Name Affiliation

John Hewson PCS Phosphate

Ross Smith PCS Phosphate

Barrie Winn PCS Phosphate

Susan Jordan PCS Phosphate

Randy Taylor URS 

Keith Barnett US EPA

Tina Ndoh US EPA

Anne Pope US EPA

James Hirtz US EPA

Donna Lazzari ERG

3.0 Summary of Meeting

EPA gave a brief overview of the Risk and Technology Review process and the status of 

the review for the phosphate sector. EPA is in the process of concluding the risk assessment. The 

ecological risk is still in the process of evaluation. Because the risk and technology review and 

any changes to the NESHAPs are on a timeline to be proposed by the end of October, and there 
Memorandum

US EPA Meeting with PCS Phosphate

p. 2 of 2

is an extensive review process, there is limited time for industry to provide additional 

information. 

EPA gave an overview of the process to assess the risks when a persistent bioaccumulative HAP is evaluated in a risk review. A screening process is used in order to predict 

what the outcome would be of a multipathway risk assessment. A multipathway risk assessment 

takes into account the amount of HAP (in this case mercury) that would be ingested if there is a 

lake in the vicinity of the plant, and fish from the lake were consumed. 

The emissions estimates for mercury from the PCS Aurora facility’s phosphate rock

calciners were presented to PCS Phosphate and it was agreed that the estimates were correct and 

were properly calculated from the stack tests that were submitted by PCS Phosphate. 

EPA discussed the necessity to establish a MACT limit for mercury. A MACT limit was 

established for phosphate rock calciners for the phosphoric acid NESHAP during the first 

rulemaking that used particulate matter (PM) as the surrogate for all of the metal HAP. Since PM 

is not an appropriate surrogate for mercury, a limit for mercury must be established. The limit 

will be evaluated as a MACT floor. Also, EPA is required to conduct a beyond-the-floor analysis 

that considers the cost and availability of emissions controls for further reducing emissions. 

The group discussed the technical reasons why phosphate rock calciners are used at the 

Aurora facility and are not used elsewhere in the United States. The organic content of the 

phosphate ore in North Carolina is much higher than in other sources of phosphate ore. Because 

of this, an oxidation process is not capable of removing all of the carbon. Carbon affects the 

color of the final product and must be removed for some applications. Also, in the purification 

system used to produce purified phosphoric acid, the purification solvent will dissolve the carbon 

and will contaminate the solvent over time. PCS has studied other options for removing organics 

from the North Carolina ore but has not been successful in developing an economic or technical 

alternative. PCS commented that phosphate rock calciners are used in both Morocco and Israel. 

The group discussed potential methods to control mercury from phosphate rock calciners.

One method being evaluated by EPA at this time is carbon adsorption in a fixed-bed because 

carbon injection along with a fabric filter was considered a less desirable option due to the high 

moisture content of the stack gas. PCS suggested that it may be possible to use carbon injection 

and capture the carbon in the currently installed wet electrostatic precipitators. Also, the majority 

of the mercury is present in the gaseous elemental form, and a carbon that is specific to this form 

of mercury must be used.