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U.S. EPA Proposes Benzene Fenceline Monitoring for Coke Oven Facilities

Posted: August 23rd, 2023

Authors: Kyle H. 

The U.S. Environmental Protection Agency (EPA) has proposed amendments to the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for Coke Ovens: Pushing, Quenching, and Battery Stacks (PQBS) and Coke Oven Batteries (COB) at 40 CFR Part 63, Subparts CCCCC and L. These proposed revisions are a result of their Clean Air Act (CAA) mandated risk and technology review (RTR) for PQBS and their technology review for COB and address previously unregulated hazardous air pollutants (HAPs) and HAP emissions sources. As part of the proposed amendments, the U.S. EPA will require all Coke Oven Facilities to measure fugitive benzene emissions at the fenceline (where fenceline is equivalent to the perimeter) of their facility using passive samplers.

According to U.S. EPA, benzene is ever-present at coke oven facilities, accounts for about 70 percent of emissions of all volatile compounds and is a surrogate for organic HAPs from fugitive sources at these facilities. U.S. EPA proposes to require a minimum number of passive samplers collecting two-week time-integrated samples continuously, following EPA Method 325. These samples would be analyzed for benzene, background corrected for each sampling event, assessed against an annual action level, with results reported to U.S. EPA on a quarterly basis and made available to the public.

Passive Sampling

Passive sampling involves using small inert-coated metal tubes filled with an adsorbent and special cap that allows ambient air to diffuse onto the sorbent at a fixed rate, thereby retaining the compound of interest. Following a two-week sampling period, the tubes are collected and sent to a laboratory for analysis, with new tubes installed to maintain continuous sampling.

A minimum of 12 samplers are proposed, with deployment no later than one year after the effective date of the final rule for existing facilities, or by the effective date of the final rule or start up (whichever is later) for new facilities.

U.S. EPA estimates costs for fenceline monitoring to be $116,000 per year; however, these costs do not include effort associated with development of a monitoring plan, data assessment, quarterly reporting, or other quality assurance activities.

Benzene Concentration Action Level

U.S. EPA is proposing an action level of 3 micrograms per cubic meter (µg/m3) benzene based on modeled fenceline concentrations from emissions inventories associated with data for 2016 and 2022 facility-wide risk assessments. This proposed action level is intended to reflect fugitive emissions sources only and exclude background concentrations. A facility would exceed this action level when the highest of the rolling annual average fenceline concentrations (corrected for background) is greater than 3 µg/m3.

To account for background, U.S. EPA proposes that each facility would determine a delta concentration (Δc), calculated as the lowest benzene sample value subtracted from the highest benzene sample value for each two-week period. This approach is intended to subtract out any estimated contribution from background emissions that do not originate from the facility.

If the rolling annual average exceeds the concentration action level, within five days of calculating the rolling annual average, the coke oven facility must initiate a root cause analysis to determine the primary and contributing causes of the exceedance. This root cause analysis must be completed within 45 days of initiation, followed by the corrective action plan to reduce emissions. The coke oven facility would not be deemed out of compliance with the proposed concentration action level if appropriate corrective action measures are taken.

Data Reporting

To report and submit results, coke oven facilities will be required to calculate a rolling annual average within 30 days of completion of each sampling episode and report the data for each sampler within 45 days of the end of each quarterly period through U.S. EPA’s public electronic reporting and data retrieval portal. This submittal will include the individual sample results from each sampler, coordinates of all sampler locations, biweekly 12-month rolling average concentration values, and notes for each value (e.g., background corrections used, if the value was under detection, or an outlier that was removed from the data set).

What Does This Mean for my Facility?

Following collection of a year’s worth of data to generate the rolling annual average, facilities would need to demonstrate compliance with the action level within three years of the effective date of the final revised NESHAP. (We note that U.S. EPA is also proposing new standards for several unregulated HAPs and sources of HAPs at coke oven facilities that will require additional monitoring, testing, recordkeeping, and reporting.)

How can ALL4 help?

As your facility begins to plan for implementation of benzene fenceline monitoring, don’t hesitate to ask for assistance. ALL4 would be glad to discuss any of the following:

  • Developing an air monitoring plan.
  • Installation and placement of passive samplers to meet the proposed rule.
  • Collecting, processing, and submitting samples.
  • Training for facility personnel.
  • Creation of spreadsheet-like tools to record bi-weekly data and calculate annual rolling averages.
  • Analyzing raw data to subtract out background concentrations as appropriate.
  • Installation and maintaining meteorological equipment for on-site ambient meteorological data (not currently part of the rule but will help with background concentration calculations).
  • Conducting quality assurance audits to verify the collection of representative samples.
  • Preparing electronic reports for U.S. EPA.
  • Preparing root-cause analysis and corrective action plans to submit to U.S. EPA if the facility exceeds concentration action level.

We can also help with strategy around implementation of the other requirements U.S. EPA is proposing to add to the NESHAP. For more information on Benzene Fenceline Monitoring please contact Kyle Hunt at khunt@all4inc.com or 512.705.0123.


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