NON-CBI VERSION

MEMORANDUM

Date: July 23, 2014

Subject: Report of June 24, 2014 Site Visit to Dow Chemical, in Freeport Texas

From: Alden West, EC/R Incorporated 

Lesley Stobert, EC/R Incorporated

To: Paula Hirtz, EPA/OAQPS

This memorandum summarizes the visit to the Dow Chemical facility in Freeport, Texas that 

was conducted on June 24, 2014. The purpose of this visit was to better understand the processes 

used in the Offsite Waste and Recovery Operations (OSWRO) industry, the controls in place to 

reduce hazardous air pollutants (HAP) emissions, and the characteristics of the emission points at 

this facility. This information will assist the EPA in the promulgation of amendments to the 

emission standards for the OSWRO industry.

A background discussion of this project is provided, followed by an overview of the plant, a 

description of the off-site waste operations at the facility, and a summary of emission sources at 

the facility. The final section includes a summary of action items resulting from the meeting with 

Dow. 

The participants in the site visit included the following:

Russell Wozniak, Dow

Kyle Graham, Dow

Maria Valdez, Dow

Paul Lindon, Dow

Mark Kuettel, Dow

Jeana Schanzer, Dow

Elaine Schroeder, Dow

Paula Hirtz, U.S. EPA/OAQPS

Lesley Stobert, EC/R Incorporated

Alden West, EC/R Incorporated

BACKGROUND

Section 112(d) of the Clean Air Act requires the EPA to develop standards for each major source 

category listed under section 112(c). These technology-based standards are often referred to as 

maximum achievable control technology, or MACT, standards. The National Emissions 

Standards for Hazardous Air Pollutants (NESHAP) for Off-site Waste and Recovery Operations 

(OSWRO) were promulgated on July 1, 1996 (61 FR 34139) and codified at 40 CFR part 63, 

subpart DD. The Dow Chemical facility in Freeport, TX is subject to subpart DD because it 
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receives certain wastes from off-site locations for storage and treatment, recovery or disposal.

Section 112 of the Clean Air Act contains provisions requiring the EPA to periodically revisit the 

technology-based standards. Specifically, section 112(d)(6) states that the EPA shall review 

these standards and revise them “as necessary (taking into account developments in practices, 

processes, and control technologies)” no less frequently than every eight years. The second stage 

in the review process focuses on reducing any remaining (i.e., “residual”) risk according to CAA 

section 112(f). Section 112(f)(2) directs the EPA to assess the risk remaining (residual risk) after 

the application of MACT standards and promulgate additional standards as necessary to provide 

an ample margin of safety to protect public health, or to prevent, taking into consideration costs, 

energy, safety, and other relevant factors, an adverse environmental impact. On May 30, 2014, 

the EPA proposed amendments to the OSWRO MACT standards to address the results of the 

residual risk and technology review (RTR) conducted under the Clean Air Act.

A site visit of the Dow Chemical facility was conducted to better understand the current 

processes and control technologies in the OSWRO industry before promulgation of final 

amendments to the OSWRO MACT standards. As part of the RTR process, the EPA is seeking

additional information to improve the Agency’s understanding of the OSWRO processes and 

emission points, to improve the data used in site-specific emission profiles and to better 

characterize the maximum risks to surrounding populations as a result of activities at OSWRO 

facilities. Further, the May 30, 2014 proposal includes new provisions that may change the way

certain OSWRO sources are required to operate. This site visit was conducted to better 

understand the technical and operational implications of these changes based on current 

processes observed at the facility and discussions with facility personnel. 

PLANT SITE OVERVIEW

The Dow Chemical facility covers 20 square miles south of Houston in Freeport, Texas. The 

facility consists of 4 plants – Plant A, Plant B, Stratton Ridge, and Oyster Creek – each with a 

variety of operations related to the production of chemical products and precursors. Plant B is the 

largest of the four plants in both size and number of production units, and is also the only plant 

that receives and processes offsite waste. Dow Freeport is currently undergoing an expansion and 

plans to add or has recently added multiple units, including a propylene production facility, an 

ethylene cracker, an agrosciences plant, a chlor-alkali unit, and two plastics/polyethylene plants. 

This facility is a major source of HAP. In addition to the OSWRO MACT standards, OSWRO 

related operations located at Plant B are also subject to numerous other MACT regulations, 

including:

 Benzene Waste NESHAP

 Organic Liquids Distribution NESHAP

 Hazardous Organic NESHAP (HON)

 Miscellaneous Organic Chemical Production and Processes (MON)

 Hydrochloric Acid Production NESHAP

 Hazardous Waste Combustion NESHAP

 Pesticide Active Ingredient Production NESHAP
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 Site Remediation NESHAP

PROCESS DESCRIPTION

[process description information claimed as confidential business information by Dow] 

EMISSION SOURCES

Emission sources subject to the OSWRO MACT standards at the B-3300 kiln and the B-800 

thermal oxidizer units include tanks, containers, fugitives, transfer systems and control devices. 

Storage tank emissions can occur from the evaporation of liquid wastes placed in the tank. The 

storage tanks at Dow are equipped with fixed roofs to reduce evaporation of tank contents to the 

atmosphere. Tanks are also equipped with vents that provide relief from fluctuations in pressure 

resulting from normal operating conditions such as filling/emptying and changes in atmospheric 

temperature. Vapors released by the pressure vents on the tanks at B-3300 are vented to the kiln 

afterburner and vapors from the tanks at B-800 are vented to the thermal oxidizer. The kiln and 

the thermal oxidizer are considered control devices under the OSWRO MACT standards, and 

there are no flares or other control devices on the OSWRO processes at the facility. All storage 

tanks are equipped with PRDs that will emit to the atmosphere if the tank internal pressure 

exceeds the device threshold setting for safe handling of liquid waste.

Containers that store offsite waste materials are another emission source at the facility. Smaller 

containers are stored in a package facility that is open to the atmosphere and roll-off boxes are 

stored outside. All containers at the facility are controlled by a cover and closure device (e.g., a 

lid on a drum or secured tarp on a roll-off box). Additional emissions from containers can occur 

if a cover is removed for sampling or other purposes. 

Dow operates numerous valves, pump seals, flanges, open-ended lines, and other equipment 

components that could leak hazardous vapors to the atmosphere. Dow has opted to comply with 

the HON leak detection and repair (LDAR) requirements as provided for in the OSWRO MACT

standards (40 CFR §63.691(b)(2)). All components included in an LDAR monitoring program 

are physically tagged.

Transfer systems are a potential source of emissions at Dow and are subject to the OSWRO 

MACT standards. Transfer systems operated at the facility include pumps, such as those used to 

transport liquid waste from trucks at direct burn areas to the kiln, and conveyors, which are used 

to transport solid waste to the kiln. 

ACTION ITEMS

Dow agreed to look into the level of mercury emissions from OSWRO operations at their 

facility. No specific action or time period was discussed.