Enforcement Alert

United States


Environmental Protection and Compliance (revised)


Agency Assurance (2248A)


Office of Enforcement EPA 300-N-00-014 

Enforcement Alert 

Volume 3, Number 9 Office of Regulatory Enforcement October 2000 

Frequent, Routine Flaring May Cause Excessive, 

Uncontrolled Sulfur Dioxide Releases 

Practice Not Considered ‘Good Pollution Control Practice’; May Violate Clean Air Act 

About 

Enforcement Alert 

“Enforcement is 

published periodically by the 

Office 

Enforcement 

educate 

regulated 

important 

enforcement 

trends 

enforcement actions. 

This information should help 

the 

anticipate 

violations 

environmental law that could 

otherwise lead to enforcement 

action. Reproduction and wide 

dissemination 

publication are encouraged. 

For information on obtaining 

additional 

publication, contact the editor 

listed below. 

Eric V. Schaeffer 

Director, Office of 

Regulatory Enforcement 

Editor: Virginia Bueno 

(202) 564-8684 

bueno.virginia@epamail.epa.gov 

(Please Email all address and 

name changes or subscription 

requests for this newsletter.) Continued on page 2 

Flaring is an engineering practice 

that provides for process equipment to immediately release gases to a 

This publication is found on the Internet at http://www.epa.gov/oeca/ore/enfalert 

in a manner consistent with good air 

pollution practices for minimizing emissions. New “clean fuels” requirements 

will lead to the removal of even greater 

Frequent and routine use of flares 

may not be good air pollution control 

practice for reducing emissions. 

(Photograph courtesy of Kaldair 

Inc.) 

device (a flare) where they 

can be quickly and safely incinerated. 

flares is a good engineering 

practice because flares can 

prevent 

damages, 

fires and 

explosions, 

and injuries 

employees. Flaring also 

converts 

noxious and odorous gases released in emergencies to less 

hazardous and objectionable 

emissions by the burning of 

the gases. 

But EPA investigations suggest that flaring frequently 

occurs 

nonemergency situations or is 

used to bypass pollution control equipment. 

in unacceptably high releases 

of sulfur dioxide and other noxious pollutants and may violate the requirement 

that companies operate their facilities 

Editor’s Note: To clarify sulfur dioxide reporting requirements, this issue contains 

slight revisions to the sections, “Diagnosing, Preventing Excess Flaring,” located 

on page 3 and 

quirements for Flaring Incidents” on 

page 4. 

sue. 

Alert”

of Regulatory 

to inform and 

the public and 

community of 

environmental 

issues, recent 

and significant 

regulated community 

and prevent 

of federal 

of this 

copies of this 

The proper use of 

to 

in routine, 

This results 

“EPCRA Reporting RePlease disregard the earlier is-
EnforcementAlert 

Continued from page 1 

amounts of sulfur from feed stocks. 

Companies should ensure they have adequate capacity to treat these pollutants without resorting to excess flaring. 

Good pollution control practices include: 

1. Procedures to diagnose and 

prevent malfunctions; and 

2. Adequate capacity at the back 

end of the refinery to process acid gas. 

At petroleum refineries, flares are 

used in a variety of process areas to 

prevent hydrocarbons and waste gases 

from being released directly to the atmosphere. Since hydrocarbons are the 

primary product at refineries, companies should make every effort to avoid 

sending their products up in flames. 

Flares, however, are also used to combust acid gas—a highly concentrated 

waste stream of hydrogen sulfide gas 

(up to 90 percent pure)—and sour water stripper gas (about 30 percent pure). 

Sulfur Recovery Plants (SRPs) normally process hydrogen sulfide gas and 

sour water stripper gas. A sulfur recovery plant is a refinery process for 

producing elemental sulfur for sale but 

is also a part of the refinery’s air pollution control systems. The process converts 95 percent or more of these hydrogen sulfide gases into elemental sulfur while reducing emissions to insignificant levels. Use of a flare for combusting acid gas instead of processing 

it in the SRP produces very large uncontrolled releases of sulfur dioxide 

(SO2

) and effectively bypasses the permitted and monitored SRP emission 

point. While the flare is designed to prevent the direct release of the very toxic 

and odoriferous hydrogen sulfide during malfunctions at the SRP, EPA has 

documented situations of regular or routine use of flares for acid gas incineration instead of the expected reliance on 

the flare only for emergencies. 

One day of acid gas flaring can easily release more SO2

 than is released in 

a single year of permitted SRP activity. 

On numerous occasions, EPA has uncovered information on acid gas flaring incidents that shows that 100 tons 

or more of SO2 can be released in 

such flaring within a 24-hour period. 

A moderately sized Claus sulfur recovery plant (approximately 100 long tons 

of sulfur recovered per day capacity) 

that is subject to the New Source Performance Standards and properly operated with its pollution control device 

should emit no more than 250 parts per 

million of SO2

, a rate that corresponds to a little less than 100 tons 

annually. 

Health Dangers From 

Sulfur Dioxide 

Flaring H2S can produce high ambient concentrations of SO2

. Short-term 

exposures to elevated SO2 levels while 

at moderate exertion may result in reduced lung function accompanied by 

such symptoms as wheezing, chest 

tightness, or shortness of breath in asthmatic children and adults. Other effects 

associated with longer-term exposures 

to high concentrations of SO2, combined with high levels of particulate matter, can result in respiratory illness, alterations in the lungs’ defenses, and aggravation of existing cardiovascular disease. Those at risk include individuals 

with cardiovascular disease or chronic 

lung disease, as well as children and 

the elderly. 

Acid Gas Flaring 

Routine or nonemergency “flaring 

The NSPS defines “fuel gas” to be any gas generated and combusted at 

a refinery and identifies flares as NSPS affected facilities. A’s letter to 

Koch Petroleum Company (Dec. 2, 1999) provides a detailed explanation of 

the various types of gases subject that are to NSPS requirements because 

they meet the definition of fuel gas (see http://www.epa.gov/oeca/ore/aed). 

The NSPS exempts flaring of fuel gas from the standards for sulfur oxides and monitoring requirements only when there is a process upset or an 

emergency malfunction. (40 C.F.R.Section 60.104(a)(1)). 

glish” exemption applies only to true emergencies, and the Agency expects other flaring to be monitored and comply with applicable emission 

limits. 

EPA believes that many affected facilities at petroleum refineries may 

not be in compliance with applicable NSPS requirements (fuel gas monitoring and emission limits for fuel gas combustion devices) because of their 

routine reliance on flaring to control releases of hydrocarbons. The Agency 

also believes that, as with acid gas flaring, good air pollution control practices include investigating the causes of flaring events and taking corrective 

action to avoid or reduce the probability of their recurrence. One way to 

address these potential compliance issues may be through the proper design, operation and maintenance of flare gas recovery systems. 

Hydrocarbon Flaring Considered Fuel Gas Combustion 

Subject to NSPS 

EP

This “plain EnContinued on page 3 

October 2000 2 
EnforcementAlert 

Continued from page 2 

of acid gas” is directing that gas away 

from the recovery plant, combusting it 

at a flare and releasing sulfur dioxide to 

the atmosphere. Acid gas flaring is not 

a federally permitted operation and 

should typically only occur during a 

malfunction (a “sudden, infrequent, and 

not reasonably preventable failure of 

equipment or processes to operate in a 

normal or usual manner”) (40 C.F.R. 

Section 60.2). In EPA’s experience, frequent and repetitive acid gas flaring is 

often not due to malfunctions. Acid gas 

flaring that is routine or preventable violates the NSPS requirement for operating consistent with ‘Good Air Pollution 

Control Practices’ to minimize emissions at refineries with NSPS fuel gas 

combustion devices and affected facilities including SRPs (40 C.F.R.Section 

60.11(d)). 

Chain Reaction: Upstream 

Upsets May Result in 

Downstream Malfunctions 

Properly designed, operated and 

maintained SRPs can typically receive 

and treat all acid gas produced at the 

refinery (most also are designed to treat 

sour water stripper gas). These gases 

should not be flared except under emergency or malfunction conditions. 

Upsets in upstream process equipThe Agency also believes 

that, as with acid gas 

flaring, good air pollution 

control practices include 

investigating the causes 

of flaring events and 

taking corrective action to 

avoid or reduce the 

probability of their 

recurrence. 

ment may result in hydrocarbons or 

other contaminants entering the acid gas 

stream. Hydrocarbons can be very disruptive to the short- and long-term operation of the SRP. Historically, not 

much effort has been put into investigating and correcting the root cause of 

contamination or upsets. Instead, incidents have been simply reported as 

“malfunctions.” EPA, believes that repeated malfunctions for the same cause, 

generally, could be predicted and prevented. If flaring results from a preventable upset, EPA believes that it does 

not represent good air pollution control 

practices and that it may violate the 

CAA. 

Diagnosing, Preventing 

Excess Flaring 

Repeated or regularly occurring incidents of flaring can be anticipated and 

should not be classified as ‘malfunctions.’ For example, regularly switching between high and low sulfur crude 

may cause fluctuations of the acid gas 

feed to the SRP. This can create operational problems for the SRP and/or its 

pollution control equipment, resulting 

in a perceived need to flare. These upsets should be addressed through improved operational control systems, improved and frequent training of operators, and continued optimal performance of the SRP, not by bypassing or 

flaring acid gas and sour water stripper gas. 

Another cause of flaring is inadequate capacity of the SRP and its associated tail gas unit (TGU) to process 

all the acid gas at the refinery. Refineries should ensure that their units have 

the capacity and can handle variable volumes that may occur during different 

production levels. 

Refineries should implement the following procedures to ensure that flaring results only from a true emergency 

or malfunction: 

BP Amoco Reduces 

SO2

 Emissions from 

Flaring Nearly 75% 

From 1993 to 1995, the BP Amoco facility in Oregon, 

Ohio, experienced an annual average of 16 flaring incidents and 

released approximately 180 tons 

of SO2 . Under the procedures outlined in a Consent Decree with 

EPA, BP Amoco has been able to 

reduce that amount to an insignificant number (three flaring events 

in 1999 released a total of 49 tons 

of SO2

) and each event was attributable to a true “malfunction” as 

defined in NSPS. This was accomplished through equipment and operational changes that eliminated 

the root causes of such flaring. The 

protocol in the consent decree 

(http://www.epa.gov/oeca/ore/aed) 

serves as a model in balancing the 

concerns of Good Engineering 

Practice and good Pollution Control Practices for any flaring of acid 

gas or sour water stripper gas. 

� Conduct a root-cause analysis 

of each flaring incident to identify if any 

equipment and/or operational changes 

are necessary to eliminate or minimize 

that cause so as to reduce or avoid future flaring events. As appropriate, corrective measures should be taken and 

implemented. If the analysis shows that 

the same cause has happened before, 

the incident should not be considered a 

malfunction and corrective measures 

should be taken to prevent future occurrences; 

� Ensure there is adequate capacity at the SRP and TGU. Redundant units can prevent flaring by allowContinued on page 4 

October 2000 3 
United States

Environmental Protection Agency

Office of Regulatory Enforcement

(2248A)

1200 Pennsylvania Avenue, NW

Washington, DC 20460

Official Business

Penalty for Private Use $300

‘Enforcement Alert’ newsletter

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Continued from page 3

ing one unit to operate if the other needs

to be shut down for maintenance or an

upset; and

� Prepare an accurate estimate

of the total SO2

 released (using clear

calculation procedures) for each acid

gas flaring incident.

Identifying the root cause of the flaring incident gives the refinery the opportunity to fix the problem before it

happens again. It also enables the facility to assess whether the flaring incident was caused by a true malfunction,

which is considered acceptable engineering practices.

A reference procedure for evaluating if good air pollution practices are

being used when future acid gas flaring events occur can be found in the

Consent Decree, C.A. No. 3:97CV7790

N.D. Ohio, entered May 5, 1999 (see

http://www.epa.gov/oeca/ore/aed).

For more information, contact

Patric McCoy at U.S. EPA’s Region 5

office in Chicago at (312) 886-6869,

EPCRA Section 304 requires that unpermitted releases of extremely hazardous substances in excess of their reportable quantity be reported immediately to the State Emergency Response Commission and Local Emergency

Planning Committee.The flaring of hydrogen sulfide may require reporting if

more than 500 pounds (the reportable quantity) of SO2 are released within a

24-hour period. The Clean Air Act recognizes that accidents, malfunctions,

start ups and shut downs may cause excess emissions even when the facility has implemented reasonable measures to avoid them. However, it is still

important to alert emergency response personnel when these releases occur,

as even short periods of flaring can emit large quantities of SO2

. For example,

a medium-sized refinery with an SRP that processes 500 tons of acid gas

each day could release as much as 40 tons of SO2 at the flare in only one

hour, more than 150 times the reportable quantity.

EPCRA Reporting Requirements for Flaring Incidents

E-mail: mccoy.patric@epa.gov; and

regarding federally permitted release

questions, contact Ginny Phillips, Office of Regulatory Enforcement,

Toxics and Pesticides Enforcement

Division at (202) 564-6139,Email:

phillips.ginny@epa.gov.

Useful Compliance

Assistance Resources

CAA Applicability Determination

Index:

http://www.epa.gov/oeca/eptdd/adi.html

Technology Transfer Network

http://www.epa.gov/ttn/

Office of Regulatory Enforcement:

http://www.epa.gov/oeca/ore/

RCRA Online:

http://www.epa.gov/rcraonline/

Compliance Assistance Centers:

http://www.epa.gov/oeca/mfcac.html

Audit Policy Information:

http://www.epa.gov/oeca/ore/

apolguid.html

Small Business Gateway:

http://www.epa.gov/smallbusiness/