Evaluation of Benzene Fenceline Monitoring Program in USEPA s Proposed Refinery Sector Rule

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1 Evaluation of Benzene Fenceline Monitoring Program in USEPA s Proposed Refinery Sector Rule By: Ted Bowie, Kimberly Wahnee, David Phong, and Idania Zamora

2 Overview of Refinery Source Category 142 large (major sources) and 7 small (area source) petroleum refineries in the United States EPA: Refineries emit ~20,000 tons per year hazardous air pollutants (HAPs) Proposed rulemaking includes amendments to Maximum Achievable Control Technology (MACT) standards and New Source Performance Standards (NSPS) Data source: USEPA MACT 1 (1995) covers non-combustion or evaporative sources (e.g., equipment leaks, tanks, wastewater, miscellaneous process vents, cooling towers) MACT 2 (2002) covers combustion sources (e.g., catalytic cracking units, catalytic reforming units, and sulfur recovery units) NSPS J/Ja (2012) covers fuel gas combustion devices, FCCU, sulfur plants, delayed cokers, flares, and process heaters

3 Overview of Proposed Rule Proposal signed by EPA on May 15, 2014 Emission control requirements for storage tanks, flares, and coking units Monitoring of benzene concentrations at refinery fencelines Eliminate exemptions to emission limits during periods of startup, shutdown, and malfunction Technical corrections and clarifications to the Petroleum Refinery NSPSs

4 What Does EPA s Residual Risk Analysis Show? Risk deemed to be acceptable under 112(f) Highest maximum individual risk (MIR) estimated at 60 in a million (actuals) and 100 in a million (allowables) Highest MIR driven by naphthalene and benzene from equipment leaks Sector-wide population at risk greater than 1 in a million is predicted at 5,000,000 Cancer incidence of 0.3 cases/year driven by delayed cokers (DCU) and PAHs Maximum chronic non-cancer HI of 0.9 due to emissions hydrogen cyanide from FCCU Maximum acute non-cancer HQ of 5 due to emissions of nickel from FCCU Proposed amendments estimated to lower population at risk to 4,000,000, and reduce incidence about 18%

5 Rationale for Benzene Fenceline Monitoring Program Purpose: Backstop to detect undercounted emissions (particularly fugitives) Certain emissions sources (e.g., fugitive leaks) difficult to quantify with methods currently available Uncertainties in emissions estimates related to mischaracterization of emission sources: Exclusion of nonroutine emissions Omission of sources that are unexpected, not measured, or not considered part of the affected source Improper characterization of sources for emission models and emission factors Data source: USEPA

6 Fenceline Monitoring Requirements Small (<750 acres) 12 monitors 30 interval Medium (750-1,500 acres) 18 monitors 20 interval Large (>1,500 acres) 24 monitors 15 interval

7 Fenceline Monitoring Requirements (cont) Passive diffusive tube monitors Annual average of 2-week samples, calculated as: HFC = Maximum (MFC i OSC i ) Compare to action level of 9 μg/m 3 Calculate rolling annual average within 30 days of completion of each sampling episode If exceedance, initiate root cause analysis Develop corrective action plan and take corrective action Recordkeeping and Reporting Report fenceline data within 45 days of the end of semiannual periods Site specific ambient monitoring plan Data source: USEPA

8 Potential Issues with Benzene Fenceline Monitoring Requirements Possible community misunderstanding Monitoring results largely dependent on configuration of benzene sources Alternative chemicals may be better surrogates of fugitives from some refineries Identification of background or offsite contributors difficult with passive sampling approach Monitoring provides little (if any) information regarding which sources to control Significant cost No offramp for refineries with low benzene concentrations

9 Public Relations Fenceline concentrations are not representative of chronic risks, but some members of the public may misunderstand the data Stated purpose of benzene monitoring is to detect un-reported emissions, but Some might attempt to equate benzene concentrations to risks Data will be publically available

10 Is Benzene the Best Surrogate for Fugitives? Benzene Total VOCs Average Fugitive Emissions (% of total) 64% 64% Total Emissions (1,000 TPY) Facility Counts Total VOCs might be a better surrogate Not all facilities have large benzene emissions Larger emissions of VOCs easier to measure/detect Affordable, real-time instrumentation for measurement of total VOCs (e.g., PID) allows correlation with wind direction

11 Identification of Background Difficult with Passive Sampling Facility 1 Facility 2 Facility 3

12 Identification of Background Difficult with Passive Sampling (cont) Facility 1 Facility 2 Facility 3

13 Identification of Offsite Contributors Difficult with Passive Sampling Facility 1 Facility 2 Facility 3

14 Identification of Offsite Contributors Difficult with Passive Sampling (cont) Facility 1 Facility 2 Facility 3

15 Configuration Determines Whether Monitoring Provides Information on Which Sources to Control

16 Significant Cost Model Plant Costs for Fenceline Monitoring Capital Costs (US$) In-House Analysis Outsourced Analysis Annualized Cost (US$) In-House Analysis Outsourced Analysis Small 85,440 21,370 36,300 64,200 Medium 86,650 22,580 41,000 86,900 Large 88,270 23,960 45, ,700 Does not include costs for: Site specific monitoring plan Root cause analysis Corrective action plan and implementation

17 Strategies to Overcome Program Limitations Conduct dispersion modeling Identify which sources are driving benzene concentrations Identify benzene hot spots Perform meteorological data analysis Determine if winds are consistent, or if diurnal or seasonal variations are present Identify which monitors are upwind and downwind (if possible)

18 Strategies to Overcome Program Limitations (cont) Consider additional monitors Offsite monitors can help tease out background and offsite sources Onsite monitors can help identify larger fugitive sources (e.g., LDAR) Consider focused real-time monitoring Determine if concentrations due to onsite or offsite sources Identify and correct problems quicker than with passive approach Options range from simplistic (e.g., PID) to more sophisticated (e.g., UV-DOAS)

19 Questions? Ted Bowie, MS, PE, CIH ENVIRON International Corporation San Francisco, California