Proposed Amendments to Integrated Iron and Steel Manufacturing MACT Standards
Posted: November 9th, 2023
Authors: Roy R. Michael H.
On July 31, 2023, the U.S. Environmental Protection Agency (EPA) proposed amendments to 40 CFR Part 63, Subpart FFFFF, National Emission Standards for Hazardous Air Pollutants (NESHAP) from Integrated Iron and Steel Manufacturing Facilities (Subpart FFFFF). Subpart FFFFF applies to facilities under the NAICS code 331110, or any facility engaged in producing steel from refined iron ore. There are currently eight operating facilities and one idle facility in this source category. U.S. EPA is updating the technology review promulgated in July 2020.
What is changing?
U.S. EPA has proposed new and revised emissions limits based on maximum achievable control technology (MACT) for point and fugitive sources located at integrated iron and steel manufacturing facilities. The changes are substantial and include:
- Regulation of hazardous air pollutant (HAP) emissions from unmeasured fugitive and intermittent particulate matter sources (UFIP)
- Regulation of five unregulated HAPs from sinter plants
- Regulation of three unregulated HAP from blast furnace stoves (BF) and basic oxygen process furnaces (BOPF)
- Regulation of two unregulated HAP from BF
- Revision of the dioxin/furan (D/F) and polycyclic hydrocarbon (PAH) standards for sinter plants.
- A new requirement for fenceline chromium (Cr) monitoring at each Facility to ensure that the proposed work practice standards and emissions limits are achieving anticipated results.
Summaries of the revisions are provided below.
Proposed New UFIP Requirements
Summaries of the proposed changes to the five UFIP sources are provided below.
BF Unplanned Bleeder Valve Openings
BF unplanned bleeder valve openings are unexpected openings of the bleeder valves due to pressure surges that can occur when raw materials build up at the top of the BF and fall (slip). U.S. EPA has proposed new operational limits listed below:
- Existing Sources: Five unplanned openings per furnace, per year
- New Sources: Zero unplanned openings per furnace, per year (new sources)
U.S. EPA determined that five unplanned openings per furnace per, year was the MACT floor level of performance for the existing units. The best performing BF reported zero unplanned openings, which resulted in the proposed new source operational limit.
U.S. EPA also proposed the following work practice standards to prevent large raw material slips from occurring:
- Install and operate devices to continuously measure/monitor material levels in the furnace at a minimum of three locations and using alarms to inform operators of static conditions that indicate a slip may occur.
- Install and operate instruments such as a thermocouple and transducer on the furnace to monitor temperature and pressure to help determine when a slip may occur.
- Install a screen to remove fine particles from raw materials.
- Develop and submit a plan to the U.S. EPA for approval that explains how the facility will implement these requirements.
U.S. EPA has also proposed a new requirement for facilities to submit a semi-annual unplanned bleeder valve report to include the date, time, duration, and any corrective actions taken in response to unplanned openings.
BF Planned Bleeder Valve Openings
BF planned bleeder valve openings are bleeder valve openings initiated by an operator as part of a furnace startup, shutdown, or temporary idling for maintenance. Planned openings occur after the BF is turned down, which results in less emissions than during unplanned openings. U.S. EPA has proposed the following new opacity limits for such openings:
- 8% opacity for any 6-minute averaging period of the BF planned bleeder valve openings for existing sources.
- 0% opacity for any 6-minute averaging period of the BF planned bleeder valve opening for new sources.
U.S. EPA suggests that preemptive actions prior to planned openings such as tapping as much liquid out of the furnace as possible, removing fuel or and/or stopping fuel injection, and lowering the bottom pressure can help to minimize visible emissions, but did not propose any work practice standards for planned openings to allow facilities flexibility in determining how they will comply with the opacity standards.
BF and BOPF Slag Processing, Handling, and Storage
Slag is skimmed from the surface of molten iron or steel and transported to pits for cooling. Fugitive emissions can occur during slag dumping, storage, removal or recovery, and handling.
U.S. EPA has proposed a new opacity limit for visible emissions from slag pits during slag handling, storage, and processing:
- Existing Sources: 5% opacity based on a 6-minute average.
- New sources: 2.5% opacity based on a 6-minute average.
The existing source opacity limit reflects a beyond the floor standard because there are work practices available that are not requirements but can assist in minimizing emissions, such as applying a water spray or droplets, installing wind screens, dust suppression misters, maintain high moisture content of slag during handling, storage, and processing operations.
BF Bell Leaks
Blast furnace charge systems typically include a system of large and small “bells” that serve as a lock system to prevents blast furnace gases from escaping during furnace charging. The metal seals of the bells mechanically wear down over time from use. . As the seals wear, they lose their effectiveness and allow BF gases to escape into the atmosphere.
U.S. EPA has proposed a new operating requirement to observe the top of the BF monthly for visible emissions using EPA Method 22. If there is a visible plume present via EPA Method 22, an EPA Method 9 test to determine opacity would be required. If visible emissions determined by EPA Method 9 test are greater than a 10% opacity “action level” based on a 3-minute average, then the large bell seals would need to be repaired or replaced within the next 4 months.
The newly proposed requirement for small bells seals is to replace or repair seals prior to a facility-specific metal throughput limit that has been proven and documented to produce no opacity from the small bells.
Beaching of Iron BFs
“Beaching” occurs when hot iron from a BF is dumped onto the ground because the BOPF cannot accept the iron, which results in fume generation. EPA has proposed a new work practice standard that will require facilities to have full or partial enclosures for the beaching process or to use CO2 to suppress the associated fumes and minimize the height, slope, and speed of beaching.
BOPF Shop Standards
BOPF shop fugitive emissions are associated with various operations (e.g., hot metal and scrap charging, tapping steel, hot metal transfer, metallurgical processes, etc.) and escape through building openings (e.g., roof vents, doors, and other openings). The EPA has proposed to reduce the existing BOPF shop 20% opacity limit to 5% (3-minute average) and to add the following work practice standards:
- Keep all openings, except roof monitors (vents) and other openings that are part of the designed ventilation of the facility, closed during tapping and material transfer.
- Conduct regular inspections of BOPF shop structure for unintended openings and leaks.
- Optimize positioning of hot metal ladles with respect to hood face and furnace mouth.
- Monitor opacity twice per month from all openings, or from the one opening known to have the highest opacity for a full steel cycle (which must include the tapping event).
- Develop and operate according to an “Operating Plan” to minimize fugitives and detect openings and leaks.
BF Casthouse Fugitive Emissions
Blast Furnace Casthouse fugitive emissions are similar to the BOPF Shop emissions and exit through roof vents, open doors, and other openings. The current NESHAP limit for fugitive emissions is 20% opacity for existing sources and 15% opacity for new sources, based on a 6-minute average. EPA has proposed a revised opacity limit of 5% based on a 6-minute average for both new and existing sources. Opacity measurement would take place during tapping at least two times per month. Under 40 CFR 63.7823(c)(2), tapping begins when the furnace is opened, usually creating a hole at the bottom of the furnace, and ends when the hole is plugged. The EPA has not proposed specific work practices but has proposed a new requirement to keep all openings, except roof monitors, closed during tapping and material transfer events.
New Limits on Previously Unregulated HAPs
U.S. EPA has proposed new point source emissions limits for new regulated pollutants from Sinter Plants, BF Stoves and BOPFs, and BFs. These limits are proposed to fulfil the requirement that all HAPs from affected sources are regulated. The proposed limits are summarized in the table below.
| Process | HAP | Proposed MACT Limit |
| Sinter Plants | CS2 | Existing and new sources: 0.028 lb/ton sinter |
| Sinter Plants | COS | Existing sources: 0.064 lb/ton sinter
New sources: 0.030 lb/ton sinter |
| Sinter Plants | HCl | Existing sources: 0.025 lb/ton sinter
New sources: 0.0012 lb/ton sinter |
| Sinter Plants | HF | Existing and new sources: 0.0011 lb/ton sinter. |
| Sinter Plants | Hg | Existing sources: 3.5E–5 lb/ton sinter.
New sources: 1.2E–5 lb/ton sinter. |
| BF casthouse control devices | HCl | Existing sources: 0.0013 lb/ton iron.
New sources: 5.9E–4 lb/ton iron. |
| BF casthouse control devices | THC | Existing sources: 0.092 lb/ton iron.
New sources: 0.035 lb/ton iron. |
| BOPF | D/F (TEQ) | Existing and new sources: 4.7E–8 lb/ton steel |
| BOPF | HCl | Existing sources: 0.078 lb/ton steel
New sources: 1.9E–4 lb/ton steel |
| BOPF | THC | Existing sources: 0.04 lb/ton steel
New sources: 0.0017 lb/ton steel |
| BF Stove | D/F (TEQ) | Existing and new sources: 3.8E–10 lb/ton iron |
| BF Stove | HCl | Existing sources: 5.2E–4 lb/ton iron
New sources: 1.4E–4 lb/ton iron |
| BF Stove | THC | Existing sources: 0.1 lb/ton iron
New sources: 0.0011 lb/ton iron |
Revised D/F and PAH Standards for Sinter Plants
U.S. EPA has proposed revised point source emissions limits for D/F and PAH from Sinter Plants. U.S. EPA determined that activated carbon injection (ACI) was not cost effective and proposed limits of 3.5E-08 lbs/ton of sinter for D/F and 5.9E-03 lbs/ton of sinter for PAHs for existing sinter plant windboxes. For new sinter plant windboxes, U.S. EPA proposed limits of 3.1E-09 lbs/ton of sinter for D/F (TEQ) and 1.5E-03 lbs/ton of sinter.
Fenceline Monitoring
U.S. EPA has proposed that facilities place four ambient air monitors at or near their fenceline at appropriate locations around the facility perimeter facility based on an approved site-specific plan. The ambient monitors will collect samples every 6th day for chromium analysis. Chromium was chosen as the pollutant to be measured because it was deemed a good surrogate for other HAP metals, including arsenic. The proposed action level for chromium is 0.1 μg/m3 based on a 12-month rolling average “delta c” concentration. The delta c concentration is determined as the highest sample value for a given sample period, minus the lowest sample value measured during that period. If the delta c concentration 12-month rolling average is greater than the proposed action level, then the facility must conduct a root cause analysis and take corrective action to prevent additional exceedances. The data from the fenceline monitoring will be reported through EPA’s CEDRI portal on a quarterly basis and will be available to the public via WebFIRE.
There is also a proposed sunset provision for fenceline monitoring. If the facility’s 12-month average value remains less than or equal to 50% of the proposed action level (0.1 μg/m3) for a 24-month period, the facility could discontinue fenceline monitoring as long as they continue to comply with all other requirements of the NESHAP.
Compliance Deadlines for the Proposed Additional Requirements
EPA’s proposed compliance dates for the new requirements are summarized below.
| Source | Proposed Requirement | Proposed Compliance Date |
| All affected sinter plant windbox sources that commence construction or reconstruction on or before July 31, 2023.
|
Proposed new emissions limits for mercury, HCl, HF, CS2, COS, D/F, and PAH. | 6 months after the promulgation date of the final rule. |
| All affected sources that commence construction or reconstruction on or before July 31, 2023. | Proposed fenceline monitoring requirements.
|
1 year after the promulgation of the fenceline method for metals or 2 years after the promulgation date of the final rule, whichever is later. |
| Proposed opacity limits and work practices for the seven UFIP sources. | 12 months after the promulgation date of the final rule. | |
| All affected BF and BOPF sources that commence construction or reconstruction on or before July 31, 2023.
|
Proposed new emissions limits for HCl, THC, and D/F. | 6 months after the promulgation date of the final rule. |
| All affected sources that commence construction or reconstruction after July 31, 2023. | All proposed new and revised provisions. | Effective date of the final rule (or upon startup, whichever is later). |
What’s Next?
There are multiple proposed compliance dates ranging from 6 months to 2 years after the promulgation date. The compliance dates are dependent upon whether the proposed change will require installation of monitors, equipment, or new procedures. The comment period ended on September 14, and the final rule is expected to be signed in March 2024.
ALL4 staff are experienced in planning for and implementing updated air regulatory requirements, including fenceline monitoring. If you have any questions on this rule or would like help preparing for these new requirements, please contact Roy Rakiewicz at rrakeiwicz@all4inc.com or Michael Harris at mharris@all4inc.com.
