November 2, 2009

Melanie King

Energy Strategies Group

Sector Policies and Programs Division

Office of Air Quality Planning and Standards

U.S. Environmental Protection Agency

Mail Code D243-01

RTP, NC 27711

Re: Submittal of Additional Data for the Amendments to the RICE NESHAPs, Part 

63, Subpart ZZZZ 

Dear Ms. Melanie King,

The American Petroleum Institute (API) is a national trade association with nearly 400 member 

companies that are involved with all aspects of the oil and natural gas industry. We are pleased 

to submit additional information for your consideration for the above referenced proposed 

rulemaking in the form of the following three documents:

Support for Use of Management Practices in the National Emission Standards for 

Hazardous Air Pollutants Standards for Reciprocating Internal Combustion Engines at 

Area Sources in Rural Locations

Reciprocating Internal Combustion Engine National Emission Standard for Hazardous 

Air Pollutants (RICE NESHAP) Proposed Revisions – Emission Control Cost Analysis 

Background for “Above the Floor” Emission Controls for Natural Gas-Fired RICE

50 to 500 HP Diesel Engines (CI RICE) Analysis

API would like to make the following points that are not included in the above documents. 

1. Due to shortness of time, API is unable to prepare cost effectiveness tables for diesel 

engines for either the Above the Floor or Rural Area Source documents. However, we 

believe the cost-effectiveness for catalyst on diesel engines is likely to be comparable to 

Matthew Todd

1220 L Street, NW

Washington, DC 20005

USA

Telephone 202-682-8319

Email toddm@api.org

www.api.org
the general results in our attached report for gas-fired engines. A few points on how cost 

effectiveness relates to diesel engines are:

a. A large portion of the diesel engines in the oil & gas sector are located in Alaska.

Due to their remoteness, costly catalyst add-on controls can be significantly 

higher and warrant management practices. API supplied cost data for diesel 

engines within prior comments submitted to the docket.

b. Like SI engines, a management practice alternative is also warranted for diesel 

engines located at area sources in rural locations. 

c. Generally, diesel engines only operate a few weeks or months per year. This is 

comparable to the 1000 hr/year estimate that EPA assumed in docket document 

#EPA-HQ-OAR-2008-0708-0017. However, API’s cost effectiveness results are 

at least a factor of four, and typically a factor of ten or more, higher than the 

referenced proposed rule cost estimates. If API’s cost effectiveness values are 

used as a comparison, then adjustment from the 2,800 or 6,500 hr/year for SI to 

1,000 hr/year for CI would be needed, which would make the cost per ton of 

reduction even higher. 

d. For emergency and limited use diesel engines, the cost per ton of formaldehyde 

reduced would be much higher since these engines operate less than 100 hours per 

year.

2. EPA's above the floor emission limits included both a percent reduction threshold and an 

emission threshold. Either of these values can be used to prove compliance. For the 

emission limit, EPA started the calculation from the MACT floor value. During 

additional discussions with EPA, API mentioned that the above the floor emission limit 

should not have been calculated by reducing the MACT floor emission limit by the 

percent reduction required across the catalyst. Instead, API suggested that the above the 

floor emission limit should start from a reasonably high emission value for existing 

engines exhaust pre-catalyst. This emission level would allow engine operators with 

well designed and maintained engines to get longer life out of the catalyst, while allowing 

operators with older engines to maintain compliance via catalyst maintenance.

3. The above the floor economic analysis assumes that all engines can comply with the rule 

by simply adding a catalyst. However, industry does not have any experience with 

installing catalyst on many makes and sizes of engines. For example, many older and 

small engines use magneto style timing equipment. These engines may need to be 

retrofitted with new electronic ignitions systems to stabilize the combustion operations 

sufficiently for the AFR controller and catalyst systems to function reliably. Overhauls 

may need to be completed more often to reduce oil consumption that will foul the catalyst 

and require more frequent cleaning and replacement of the catalyst. Requirements of this 

type are currently unknown for many existing engine types and most small engines.

Thus, the economic analysis included in this paper has potential to be significantly under 

estimated.

4. Even with a recently developed “premium catalyst”, the catalyst manufacture can only 

guarantee an emission reduction of 73% (reference letter from Bruce Chrisman of 

Cameron to Melanie King) for the 2SLB RICE that has been tested. EPA should reduce 

the catalyst reduction efficiency for 2SLB RICE to 73% at most. Even if this 

recommendation is adopted, many 2SLB engines may still require significant additional 

expense to achieve compliance as discussed in item #3 above. 
We appreciate the opportunity to submit this supplemental information and would welcome a 

conference call to discuss further. 

Sincerely,

Matthew Todd

Cc Bob Wayland, EPA