73272 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

BALNN, GA WP (lat. 34°56′34.20′′ N, long. 083°54′56.42′′ W) 

BURGG, SC WP (lat. 35°02′00.55′′ N, long. 081°55′36.86′′ W) 

GAFFE, SC WP (lat. 35°05′38.90′′ N, long. 081°33′23.92′′ W) 

CRLNA, NC WP (lat. 35°12′49.48′′ N, long. 080°56′57.32′′ W) 

LOCAS, NC FIX (lat. 35°12′05.18′′ N, long. 080°26′44.89′′ W) 

RELPY, NC WP (lat. 35°12′45.70′′ N, long. 079°47′28.76′′ W) 

GMINI, NC WP (lat. 35°12′23.01′′ N, long. 079°34′01.98′′ W) 

JIMYV, NC WP (lat. 35°24′52.67′′ N, long. 079°17′16.76′′ W) 

ACUTE, NC FIX (lat. 35°36′35.10′′ N, long. 079°03′53.81′′ W) 

Raleigh/Durham, NC 

(RDU) 

VORTAC (lat. 35°52′21.08′′ N, long. 078°47′00.03′′ W) 

BOUSY, VA WP (lat. 36°49′04.41′′ N, long. 077°54′05.08′′ W) 

THHMP, VA WP (lat. 37°29′29.47′′ N, long. 077°19′08.75′′ W) 

SVILL, VA FIX (lat. 37°47′11.11′′ N, long. 077°01′56.89′′ W) 

TAPPA, VA FIX (lat. 37°58′12.66′′ N, long. 076°50′40.62′′ W) 

* * * * * * * 

T–480 Greensboro, NC (GSO) to ZOLMN, NC [New] 

Greensboro, NC (GSO) VORTAC (lat. 36°02′44.49′′ N, long. 079°58′34.94′′ W) 

MCDON, VA WP (lat. 36°40′29.56′′ N, long. 079°00′52.03′′ W) 

MAZON, VA FIX (lat. 36°45′23.24′′ N, long. 077°22′02.91′′ W) 

COUPN, VA WP (lat. 36°42′50.83′′ N, long. 077°00′44.04′′ W) 

Elizabeth City, NC 

(ECG) 

VOR/DME (lat. 36°15′27.26′′ N, long. 076°10′32.15′′ W) 

RTBRO, NC FIX (lat. 35°55′13.85′′ N, long. 075°41′49.05′′ W) 

ZOLMN, NC FIX (lat. 35°38′42.35′′ N, long. 075°24′27.41′′ W) 

T–482 MEYER, NC to COUPN, VA [New] 

MEYER, NC FIX (lat. 36°12′49.33′′ N, long. 078°04′36.13′′ W) 

COUPN, VA WP (lat. 36°42′50.83′′ N, long. 077°00′44.04′′ W) 

T–488 TAR RIVER NC (TYI) to RTBRO, NC [New] 

Tar River, NC (TYI) VORTAC (lat. 35°58′36.21′′ N, long. 077°42′13.43′′ W) 

RTBRO, NC FIX (lat. 35°55′13.85′′ N, long. 075°41′49.05′′ W) 

* * * * * 

Issued in Washington, DC, on October 19, 

2023. 

Karen L. Chiodini, 

Acting Manager, Rules and Regulations 

Group. 

[FR Doc. 2023–23479 Filed 10–24–23; 8:45 am] 

BILLING CODE 4910–13–P 

CONSUMER PRODUCT SAFETY 

COMMISSION 

16 CFR Part 1408 

[CPSC Docket No. CPSC–2019–0020] 

Safety Standard for Residential Gas 

Furnaces and Boilers 

AGENCY: Consumer Product Safety 

Commission. 

ACTION: Notice of proposed rulemaking; 

notice of opportunity for oral 

presentation of comments. 

SUMMARY: The U.S. Consumer Product 

Safety Commission (Commission or 

CPSC) has determined preliminarily 

that there is an unreasonable risk of 

injury and death associated with 

residential gas fired central furnaces, 

boilers, wall furnaces, and floor 

furnaces (gas furnaces and boilers). To 

address this risk, the Commission 

proposes a rule to detect and prevent 

dangerous levels of carbon monoxide 

(CO) production and leakage from 

residential gas furnaces and boilers. The 

Commission is providing an 

opportunity for interested parties to 

present written and oral comments on 

this notice of proposed rulemaking 

(NPR). 

DATES: Deadline for Written Comments: 

Written comments must be received by 

December 26, 2023. 

Deadline for Request to Present Oral 

Comments: Any person interested in 

making an oral presentation must send 

an email indicating this intent to the 

Office of the Secretary at cpsc-os@

cpsc.gov by December 26, 2023. 

ADDRESSES: 

Written Comments: Comments related 

to the Paperwork Reduction Act aspects 

of the proposed rule should be directed 

to the Office of Information and 

Regulatory Affairs, OMB, Attn: CPSC 

Desk Officer, FAX: 202–395–6974, or 

emailed to oira_submission@

omb.eop.gov. 

Other written comments in response 

to the proposed rule, identified by 

Docket No. CPSC–2019–0020, may be 

submitted by any of the following 

methods: 

Electronic Submissions: Submit 

electronic comments to the Federal 

eRulemaking Portal at: 

www.regulations.gov. Follow the 

instructions for submitting comments. 

CPSC typically does not accept 

comments submitted by email, except as 

described below. CPSC encourages you 

to submit electronic comments by using 

the Federal eRulemaking Portal, as 

described above. 

Mail/hand delivery/courier Written 

Submissions: Submit comments by 

mail/hand delivery/courier to: Office of 

the Secretary, Consumer Product Safety 

Commission, 4330 East West Highway, 

Bethesda, MD 20814; telephone: (301) 

504–7479. If you wish to submit 

confidential business information, trade 

secret information, or other sensitive or 

protected information that you do not 

want to be available to the public, you 

may submit such comments by mail, 

hand delivery, courier, or you may 

email them to: cpsc-os@cpsc.gov. 

Instructions: All submissions must 

include the agency name and docket 

number. CPSC may post all comments 

without change, including any personal 

identifiers, contact information, or other 

personal information provided to: 

www.regulations.gov. Do not submit 

through this website: confidential 

business information, trade secret 

information, or other sensitive or 

protected information that you do not 

want to be available to the public. If you 

wish to submit such information, please 

submit it according to the instructions 

for mail/hand delivery/courier written 

submissions. 

Docket for NPR: For access to the 

docket to read background documents 

or comments received, go to: 

www.regulations.gov, insert the docket 

number CPSC–2019–0020 into the 

‘‘Search’’ box, and follow the prompts. 

FOR FURTHER INFORMATION CONTACT: 

Ronald A. Jordan, Directorate for 

Engineering Sciences, Mechanical 


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Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 73273 

1The Commission voted (4–0) to publish this 

notice of proposed rulemaking as drafted. 

Commissioner Feldman issued a statement in 

connection with his vote, available at: https://

www.cpsc.gov/s3fs-public/Comm-Mtg-Min-InfantRockers-NPR-and-Gas-Furnaces-and-BoilersNPR.pdf?VersionId=8Ct.NBI7RhSXyoz

TJBE65q3lCSyU_aMl. 

Engineering, Consumer Product Safety 

Commission, National Product Testing 

and Evaluation Center, 5 Research 

Place, Rockville, MD 20850; telephone: 

301–987–2219; rjordan@cpsc.gov. 

SUPPLEMENTARY INFORMATION: 

I. Background 

On August 19, 2019, the Commission 

published an advance notice of 

proposed rulemaking (ANPR) to develop 

a rule to address the risk of injury 

associated with residential gas furnaces 

and boilers from CO production and 

leakage. 84 FR 42847. The Commission 

received 15 comments. The Commission 

is now proceeding with this proposed 

rulemaking.1 The information discussed 

in this preamble is derived from CPSC 

the Staff Briefing Package for the NPR, 

which is available on CPSC’s website at: 

https://www.cpsc.gov/s3fs-public/ 

Notice-of-Proposed-Rulemaking-SafetyStandard-for-Residential-Gas-Furnacesand-Boilers-COMBINED-PDFS.

pdf?VersionId=7BJ3c6EeDF78

nHorx2mCEr94XygwgeQV. 

II. Statutory Authority 

This rulemaking falls under the 

authority of the CPSA, (Consumer 

Product Safety Act) 15 U.S.C. 2051– 

2089. Section 7(a) of the CPSA 

authorizes the Commission to 

promulgate a mandatory consumer 

product safety standard that sets forth 

performance or labeling requirements 

for a consumer product, if such 

requirements are reasonably necessary 

to prevent or reduce an unreasonable 

risk of injury. 15 U.S.C. 2056(a). Section 

9 of the CPSA specifies the procedure 

that the Commission must follow to 

issue a consumer product safety 

standard under section 7 of the CPSA. 

In accordance with section 9, the 

Commission commenced this 

rulemaking by issuing an ANPR. 

According to section 9(f)(1) of the 

CPSA, before promulgating a consumer 

product safety rule, the Commission 

must consider, and make appropriate 

findings to be included in the rule, on 

the following issues: 

(A) The degree and nature of the risk 

of injury that the rule is designed to 

eliminate or reduce; 

(B) the approximate number of 

consumer products, or types or classes 

of product, subject to the rule; 

(C) the need of the public for the 

products subject to the rule and the 

probable effect the rule will have on 

utility, cost, or availability of such 

products; and 

(D) the means to achieve the objective 

of the rule while minimizing adverse 

effects on competition, manufacturing, 

and commercial practices consistent 

with public health and safety. 

15 U.S.C. 2058(f)(1). 

Under section 9(f)(3) of the CPSA, to 

issue a final rule, the Commission must 

find that the rule is ‘‘reasonably 

necessary to eliminate or reduce an 

unreasonable risk of injury associated 

with such product’’ and that issuing the 

rule is in the public interest. 15 U.S.C. 

2058(f)(3)(A) and (B). Additionally, if a 

voluntary standard addressing the risk 

of injury has been adopted and 

implemented, the Commission must 

find that: 

• The voluntary standard is not likely 

to eliminate or adequately reduce the 

risk of injury, or 

• substantial compliance with the 

voluntary standard is unlikely. 

15 U.S.C. 2058(f)(3)(D). The 

Commission also must find that 

expected benefits of the rule bear a 

reasonable relationship to its costs and 

that the rule imposes the least 

burdensome requirements that would 

adequately reduce the risk of injury. 15 

U.S.C. 2058(f)(3)(E) and (F). 

III. The Product 

Central furnaces, boilers, wall 

furnaces, and floor furnaces fueled by 

natural gas or propane (gas furnaces and 

boilers) are used to heat all categories of 

consumer dwellings. These products 

burn a mixture of gas and air within the 

combustion chamber of a heat 

exchanger. As the mixture of fuel and 

air is burned, heat is released and 

transferred through the wall of the heat 

exchanger to the medium surrounding 

the heat exchanger and circulated 

through air ducts (for central furnaces), 

water pipes throughout the dwelling (for 

boilers), or directly into the ambient air 

to provide heat (for wall furnaces and 

floor furnaces). 

Burning the mixture of fuel and air 

results in the formation of combustion 

products that are typically composed of 

oxygen, carbon dioxide, water vapor, 

and CO. The combustion products are 

exhausted to the outdoors through a 

vent system, either vertically through 

the roof or horizontally through a side 

wall through the vent pipe. When the 

mixture of fuel and air is burned 

completely, the concentration of CO 

produced should remain relatively low. 

However, when issues arise with the 

combustion process (such as fuel-air 

mixtures that are not optimal), 

dangerous levels of CO can be 

produced. The combination of 

production of dangerous levels of CO 

during the combustion process and 

leakage of that CO through the vent 

system into the living space is a 

potentially deadly hazard pattern 

identified by CPSC staff. 

In a gas-fired central furnace (Figure 

1), air is the medium that surrounds and 

is heated by the heat exchanger. A large 

fan is used to force-circulate the heated 

air across the exterior surfaces of the 

heat exchanger, through a duct system, 

and then the heated air exits the duct 

system through warm air registers 

typically within the dwelling. The 

arrow in Figure 1 depicts the vent pipe. 

In a gas boiler (Figure 2), water or 

steam is the medium that surrounds and 

is heated by the heat exchanger. The 

heated water or steam is circulated, 

using a pump to force the fluid through 

a piping system to radiators typically in 

each room in the dwelling. Living areas 

are heated through radiative and 

conductive heat transfer from the heated 

water or steam supplied to the radiators 

to the room. Gas-fired central furnaces 

and boilers are considered central 

heating appliances because they provide 

heat to each room of a dwelling. The 

arrow in Figure 2 points to the boiler’s 

vent pipe. 


lotter on DSK11XQN23PROD with PROPOSALS1
73274 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

In addition to central gas-fired 

furnaces and boilers, the proposed 

scope of the NPR also includes gas wall 

furnaces (Figure 3) and gas floor 

furnaces (Figure 4). As their names 

indicate, gas wall furnaces are installed 

in wall spaces, typically between the 

wall stud framing members; and floor 

furnaces are installed in the floor, 

typically between the floor joist framing 

members. Wall furnaces and floor 

furnaces provide localized heating 

directly to the room in which they are 

located, and indirectly to adjoining 

rooms within the dwelling. The 

combustion products of wall furnaces 

are vented to the outdoors, either 

vertically through the roof, or 

horizontally through a side wall with 

the vent pipe running along the length 

of the wall studs between which the 

unit is installed. The combustion 

products of a floor furnace are typically 

vented horizontally through a side wall, 

with the vent pipe running along the 

length of the floor joists between which 

the unit is installed and through an 

exterior wall. 


lotter on DSK11XQN23PROD with PROPOSALS1EP25OC23.003</GPH> EP25OC23.004</GPH>

Figure 1. Gas-fired central furnace Figure 2. Gas boiler 

Figure 3. Gas wall furnace Figure 4. Gas floor furnace 
Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 73275 

2Non-Fire Carbon Monoxide Deaths Associated 

with the Use of Consumer Products 2019 Annual 

Estimates. J. Topping. CPSC Directorate for 

Epidemiology. March 2023. https://www.cpsc.gov/ 

s3fs-public/NonFireCarbonMonoxideDeaths

AssociatedwiththeUseofConsumer

Products2019AnnualEstimates.pdf?

VersionId=90WCZoH61aVUrTgDt

Oo16LLKZf1EeH3E. 

3 Draft Advance Notice of Proposed Rulemaking: 

Performance Requirements for Residential Gas 

Furnaces and Boilers. Retrieved at: https://cpsc.gov/ 

s3fs-public/Draft%20ANPR%20- 

%20Performance%20Requirements%

20for%20Residential%20Gas%20Furnaces

%20and%20Boilers.pdf. 

IV. Risk of Injury 

A. Incident Data 

1. Fatalities 

From the time period of 2017 to 2019 

(the most recent period for which data 

are complete), there were annually an 

estimated 21 CO-related deaths 

associated with gas furnaces and boilers 

(burning liquefied petroleum, natural 

gas, and unspecified gas).2 For the 20- 

year period, 2000 through 2019, these 

products were associated with a total of 

539 deaths from CO poisoning. Tab A of 

the Staff NPR Briefing Package provides 

further information regarding fatalities. 

2. Injury Estimates 

To estimate the number of injuries 

associated with CO exposure from 

natural gas and propane furnaces and 

boilers, an interdisciplinary team of 

CPSC staff evaluated injuries reported 

through the National Electronic Injury 

Surveillance System (NEISS) (See Tab J 

of the Staff NPR Briefing Package). Staff 

queried NEISS for data between the 

years 2014 and 2018. Staff identified 

236 nonfatal injuries related to CO 

leakages from gas furnaces and boilers 

that occurred during this period. Of the 

236 nonfatal injuries, 18 resulted in 

hospital admissions via the emergency 

department (ED), and 218 were treated 

in the ED and released. Staff used NEISS 

incidents and the Injury Cost Model 

(ICM) to extrapolate and generate 

national estimates for injuries from CO 

leakages from gas furnaces and boilers 

treated in EDs and other settings. Staff, 

using the ICM, calculated that the 

aggregate number of nonfatal injuries 

from CO leakages from gas furnaces and 

boilers from 2014 to 2018 was 30,587. 

Staff estimated that of the 30,587 

injuries, 22,817 were treated in an 

outpatient setting (e.g., doctor’s office, 

or clinic), 7,358 resulted in ED 

treatment, 333 resulted in hospital 

admissions via the ED, and 79 resulted 

in direct hospital admissions. 

B. Description of Hazard—Acute CO 

Poisoning 

In Tab C of the Staff ANPR Briefing 

Package 3 staff described the hazard 

pattern for CO poisoning associated 

with gas furnaces and boilers; which 

involves (1) hazardous levels of CO from 

incomplete combustion of the source 

fuel/gas and (2) exhaust leakage of that 

hazardous CO into the living space 

through a leak in the exhaust vent 

system. Staff’s review of the 83 

incidents, in conjunction with findings 

from earlier in-depth investigation (IDI) 

reviews, identified the following factors 

related to the incomplete combustion 

and exhaust leakage hazard patterns. 

1. Production of Dangerous Levels of CO 

From Incomplete Combustion 

Complete combustion of hydrocarbon 

fuels, such as natural gas or liquefied 

petroleum gas (LP-gas or propane), 

requires a proper mixture of air and 

fuel, as well as an adequate amount of 

heat to ignite the combustion air-fuel 

mixture. Incomplete combustion of the 

fuel supplied to gas appliances can lead 

to production of hazardous levels of CO. 

Incomplete combustion can occur when 

there is inadequate combustion of air 

(for instance when air openings to the 

appliance combustion chamber or 

burner assembly, or the exhaust outlet 

from the appliance is blocked); too 

much fuel is supplied to the appliance 

burner (i.e., over-firing); or the burner 

flame temperature falls below the 

ignition temperature of the combustion 

air-fuel mixture (i.e., flame quenching). 

Depending on the severity and duration, 

all these conditions can result in 

incomplete combustion of the fuel; 

which, in turn, can result in the gas 

furnace or boiler producing dangerous 

levels of CO. Staff’s ongoing review of 

IDIs confirms that these hazard patterns 

have not changed since the publication 

of the ANPR. 

2. Exhaust Leakage 

Combustion products produced by a 

gas furnace or boiler are normally 

vented to remove them from the home 

through a properly functioning vent 

system. A potential CO hazard in a 

home can arise if the combustion system 

of a gas furnace or boiler malfunctions 

and produces hazardous levels of CO, 

which a compromised exhaust system 

then allows to leak into the occupied 

space of the home. Typical exhaust 

failure leakage paths include a totally or 

partially blocked vent, chimney, heat 

exchanger, or a disconnected or hole in 

the vent pipe. 

Another potential leakage mechanism 

occurs when an exhaust fan or fireplace 

is installed near a gas furnace or boiler. 

The operation of an exhaust fan or a 

warm chimney created by a fireplace 

can pull air out of the room in which 

the gas furnace or boiler is installed. 

This can depressurize the room, 

resulting in reverse flow of the 

combustion products through the gas 

furnace or boiler vent system or flue 

passageways. Instead of being vented 

safely to the outdoors, depressurization 

can cause CO to spill into the living 

space. Other mechanisms that can lead 

to spillage include venting that is 

inadequate for the gas furnace or boiler 

connected to it. This can be caused by 

total or partial vent blockage, 

installation of a vent pipe that is too 

small for the gas furnace or boiler, or the 

connection of too many appliances to 

the vent. 

V. Assessment of Relevant Existing 

Voluntary Standards 

A. U.S. Voluntary Standards 

1. Description of Existing U.S. 

Voluntary Standards for Gas Furnaces 

and Boilers 

In the United States, the four types of 

gas furnaces and boilers within the 

scope of the proposed rule are covered 

by the following ANSI Z21 voluntary 

standards: 

• ANSI Z21.13–2022, Standard for 

Gas-fired low pressure steam and hot 

water boilers: This standard specifies 

construction and performance 

requirements for gas-fired, low-pressure 

steam and hot water boilers with input 

ratings of less than 12,500,000 Btu/hr 

(3,663 kW). The first edition of the 

standard was published in 1934, and the 

standard has been revised several times, 

with the latest edition published in 

2022. 

• ANSI Z21.47–2021, Standard for 

Gas-fired central furnaces: This 

standard specifies construction and 

performance requirements for gas-fired 

central furnaces with input ratings up to 

and including 400,000 Btu/hr (117 kW) 

for installation in residential, 

commercial, and industrial structures 

including furnaces for direct vent, 

recreational vehicle, outdoor, and 

manufactured (mobile) homes. The 

requirements for gas-fired central 

furnaces were initially included in 

ANSI Z21.13, before becoming a 

separate standard in 1964. From 1978 

through 1993, a separate standard for 

direct vent central furnaces (ANSI 

Z21.64) was in place before being 

consolidated into a single standard and 

harmonized with Canadian standard 

requirements in 1993, with the latest 

edition of ANSI Z21.47 published in 

2021. 

• ANSI Z21.86–2016, Standard for 

Vented gas-fired space heating 


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73276 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

4Combustion control refers to a means to control 

the combustion of a gas/air mixture to ensure 

complete combustion of the gas/air mixture and to 

limit the production of carbon monoxide. 

5 Instantaneous tankless gas water heaters provide 

heated water on demand and therefore, do not 

require the use of a large storage tank, whereas 

traditional gas storage water heaters include a large 

storage tank used to store heated water. 

appliances: This standard specifies 

construction and performance 

requirements for vented gas-fired space 

heating appliances with input ratings up 

to and including 400,000 Btu/hr (117 

kW), including gravity and fan type 

direct-vent wall furnaces and gravity 

and fan-type floor furnaces. The ANSI 

Z21.86 standard was first published in 

1998, with the latest edition published 

in 2016. 

All three ANSI standards have the 

following relevant requirements for gas 

furnaces and boilers: 

• must not produce CO in excess of 

400 ppm (under prescribed laboratory 

test conditions); 

• shut off when vent or flue is fully 

blocked; 

• shut off when blower door is not 

sealed properly (gas-fired central 

furnaces only); and 

• shut off if flames issue outside of 

the burner compartment. 

2. CPSC Voluntary Standards Activity 

In 2000, CPSC staff proposed 

voluntary standard provisions that 

would require a gas furnace (ANSI Z21/ 

83 Technical Committee subsequently 

extended the consideration of the 

proposed standards provisions to all 

vented heating appliances including 

boilers): 

• to shut down if the vent pipe 

became disconnected; and 

• to shut down if the vent pipe 

became totally or partially blocked; or 

• to have a means to prevent CO 

emissions from exceeding the standard 

limits once installed in the field; and 

• to have a means, once installed in 

the field, to shut down if CO emissions 

exceeded the standard limits. 

In 2002, the ANSI Z21/83 Technical 

Committee (TC) established a working 

group to evaluate the feasibility of using 

CO and combustion sensor technology 

to implement CPSC staff’s CO shutoff/ 

response proposal. CPSC staff 

participated in that working group from 

2002 through 2005. ANSI disbanded 

this working group in 2005 because 

manufacturers expressed concerns that 

there were no sensors commercially 

available that had the durability or 

longevity to operate within a gas furnace 

or boiler for their expected 20-year 

lifespan. CPSC staff conducted 

additional sensor testing from 2007 to 

2008 to evaluate and assess the ANSI 

ZS21/83 TC’s and working group’s 

concerns. 

In 2014, the Commission published a 

request for information (79 FR 21442) 

and hosted a Carbon Monoxide/ 

Combustion Sensor Forum to gather 

more information on the availability and 

feasibility of CO and combustion 

sensors for use in gas furnaces and 

boilers. 

In 2015, the Z21/83 TC established 

another working group to evaluate a 

new CPSC staff proposal to add 

performance requirements for CO 

Shutoff/Reponses to the voluntary 

standards for gas-fired central furnaces 

and, boilers, wall furnaces, and floor 

furnaces. The Z21/83 Technical 

Committee assessed that the technology 

required to meet the performance 

requirements was not feasible. The 

working group disbanded in 2019 

without proposing any revisions to the 

voluntary standard that would 

adequately mitigate the CO hazard 

associated with gas furnaces and boilers. 

In Tab D of the 2019 Staff ANPR 

Briefing Package, staff analyzed the 

three ANSI voluntary standards and 

concluded that none of the existing 

voluntary standards included 

requirements to protect against many of 

the known failure modes or conditions 

that have been associated with 

production and leakage of CO into 

living spaces. Since publication of the 

ANPR in August 2019, none of the 

existing ANSI voluntary standards 

discussed above have been revised to 

address the known failure modes or 

conditions associated with CO 

poisoning, such as disconnection, 

breach, or partial blocking of flues, 

vents, and chimneys. 

B. International Standards 

Existing Japanese and European gas 

appliance voluntary standards include 

CO shutoff or combustion control 4

requirements, with reliance on gas 

sensing technologies to implement those 

standards’ requirements. 

1. Japan 

The primary gas heating appliances 

used in Japan are gas water heaters, gas 

boilers, and gas space heaters. Based on 

staff’s review of the Japanese gas 

appliance market, instantaneous 

tankless gas water heaters 5 (Figure 6) 

are more common than traditional gas 

water heaters with storage tanks. 


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6 ‘‘Hydronic’’ denotes a cooling or heating system 

in which heat is transported using circulating 

water. A boiler is a type of appliance that provides 

this capability. 

The governing voluntary performance 

and safety standards in Japan are: 

• JIS–S–2109—Gas-burning water 

heaters for domestic use; 

• JIS S 2112—Gas hydronic 6 heating 

appliances for domestic use; and 

• JIS S 2122—Gas-burning space 

heaters for domestic use. 

These Japanese Industrial Standards 

(JIS) have explicit performance 

requirements for vented gas water 

heaters, gas boilers, and gas space 

heaters that require shutoff of the 

appliance in response to CO levels 

above a certain threshold (i.e., 300 ppm 

CO). The CO detection strategies 

Japanese manufacturers use to comply 

with JIS include detection of CO within 

the combustion chamber of the 

appliance and shutoff or combustion 

control in response to detection of 

hazardous levels of CO. 

2. Europe 

The relevant Committee for European 

Standardization (CEN) standards for 

residential gas boilers (depicted in 

Figure 7 below) are: 

• EN 15502–1, Gas-fired heating 

boilers, Part 1: General requirements 

and tests; 

• EN 15502–2–1, Gas-fired central 

heating boilers, Part 2–1: Specific 

standard for type C appliances and type 

B2, B3 and B5 appliances of a nominal 

heat input not exceeding 1 000 kW; and 

• EN 15502–2–2, Gas-fired central 

heating boilers, Part 2–2: Specific 

standard for type B1 appliances. 

These CEN standards include explicit 

performance requirements for gas 

boilers to either shut down before the 

CO concentration inside the flue 

exceeds 2,000 ppm or not start if the CO 

concentration exceeds 1,000 ppm. 

C. Staff Assessment of Voluntary 

Standards 

Based on staff’s analysis of the 

relevant ANSI standards, staff concludes 

that the current ANSI Z21.13–2022, 

ANSI Z21.47–2021, and ANSI Z21.86– 

2016 standards do not contain 

performance requirements to protect 

against the known failure modes or 

conditions identified by the 

Commission. Specifically, the current 

ANSI standards lack requirements (1) 

that protect against known conditions 

that cause or contribute to CO exposure 

and (2) for the appliance to monitor and 

manage CO production to prevent the 

introduction of hazardous levels of CO 

in the appliance’s exhaust vent system. 

Currently, deaths and injuries can and 

do occur from CO poisoning even when 

the furnace or boiler complies with all 

applicable existing voluntary standards 

in the U.S. Based on the above 

discussion and the analysis in the Staff 

NPR Briefing Package, the Commission 

concludes that the existing ANSI 

standards for gas furnaces and boilers 

are inadequate to address the hazards 

identified by CPSC. 

In addition, staff has researched 

international standards that required the 

same or similar performance 

requirements as staff’s 2000 and 2015 

proposals to the Z21/83 Technical 

Committee. Staff identified several gassensing technologies that were being 

used for CO shutoff or combustion 

control of residential gas appliances 

used in Japan and Europe to correspond 

with the respective standards. The COdetection strategies used by Japanese 

manufacturers include detection of CO 

within the combustion chamber of the 

appliance and shutoff or combustion 

control in response. 

In Europe, residential gas boilers are 

required to meet certain European 

combustion-efficiency requirements, as 

well as CO safety requirements. The 

combustion-control strategies used by 

European gas boiler manufacturers to 

comply with the standards are often 

accomplished by monitoring the gas/air 

mixture, the combustion flame, or the 

concentration of CO, oxygen, or carbon 

dioxide within the combustion 

products. The combustion-control 

strategies are also used to detect CO, but 

rather than causing shut-down of the 


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Figure 6. Japanese tankless gas water heater 

Figure 7. European gas boiler 
73278 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

7The proposed CO range setpoints and durations 

reflected in Table 1 are derived from UL 2034, 

Standard for Safety Single and Multiple Station 

Carbon Monoxide Alarms, 4th Edition, (2017), the 

voluntary standard for in-home carbon monoxide 

alarms. UL 2034 provides requirements for 

electrically operated single and multi-station CO 

alarms intended for protection in ordinary indoor 

locations of dwelling units. Section 41.1 of UL 2034 

provides the levels at which a carbon monoxide 

alarm must trigger. Section 1.2 of UL 2034 covers 

carbon monoxide alarms intended to respond to the 

presence of carbon monoxide from various sources, 

including the abnormal operation of fuel-fired 

appliances. 

appliance, CO production is either 

prevented or limited by modulating the 

appliance’s operation. The Japanese and 

European standards do not specify a 

minimum lifespan for sensing devices 

used to implement their respective CO 

safety and combustion efficiency 

requirements. However, adoption of the 

European and Japanese standards for 

U.S. gas furnaces and boilers would not 

be appropriate because of the design 

differences between European and 

Japanese products and U.S. gas furnaces 

and boilers, as well as the different 

regulations and standards requirements 

(other than CO safety related 

requirements) that European and 

Japanese appliances are required to 

comply with that would not apply to 

appliances made and sold in the U.S. 

VI. Technical Justification for the 

Proposed Performance Requirements 

A. Testing and Evaluation Conducted by 

Contractors 

Tab C of the Staff NPR Briefing 

Package includes links to the contractor 

reports regarding the research and 

testing conducted to assist in 

developing staff’s proposed mandatory 

performance requirements. In 2019, a 

CPSC contract was awarded to 

Guidehouse (formerly Navigant, Inc.) to 

study the impact of CO/combustion 

sensors used in residential gas boilers 

and water heaters in Europe and Japan 

and to gain a better understanding of the 

use of CO sensors in gas appliances in 

other parts of the world and their 

impact in mitigating CO risks associated 

with gas appliances. This contract work 

was also was commissioned to assess 

industry concerns about the feasibility 

of using sensors in the exhaust flue of 

gas furnaces and boilers. Work on this 

contract concluded in 2021 and the 

findings are documented in a contractor 

report titled, ‘‘Review of Combustion 

Control and Carbon Monoxide Sensors 

in Europe and Japan,’’ dated June 28, 

2021. The Guidehouse report is 

included as attachment 3 of Tab C of the 

staff NPR Briefing Package. 

The Guidehouse report found that in 

Europe, gas appliance safety is governed 

by European Union (EU) Regulation 

2016/426 on appliances burning gaseous 

fuels, and compliance with the 

applicable standard published by the 

CEN is generally considered a means to 

demonstrate compliance with the 

regulation. In Japan, the Gas Business 

Act and the Act on the Securing of 

Safety and the Optimization of 

Transaction of Liquefied Petroleum Gas 

require that a manufacturer or importer 

ensure that the gas-fired equipment 

conforms to the technical standards 

established by an Ordinance of the 

Ministry of Economy, Trade and 

Industry (METI). European and Japanese 

manufacturers limit CO production with 

combustion safety systems, combustion 

control systems, direct CO sensing in 

the exhaust path, or a combination of 

these approaches. The available data 

revealed that CO deaths and injuries in 

the EU and Japan were declining. 

However, the Guidehouse report noted 

that additional factors, such as other CO 

alarm usage and education and market 

changes, likely played a role in these 

reductions of CO deaths and injuries as 

well. 

The Guidehouse report also found the 

designs used in U.S. residential heating 

and water heating appliances differ 

significantly from those used in Japan 

and Europe. In Europe and Japan, gas 

boilers are commonly used for space 

heating and the market has transitioned 

almost entirely to condensing systems 

that utilize premix power burners. The 

Guidehouse report also found that 

appliances with design platforms based 

on premix power burners are better 

suited to incorporate combustion 

control because they typically have a 

single burner, a single heat exchanger 

cell, and a single flame ionization 

sensor to monitor the burner flame. 

CPSC also procured two contracts 

with ANSYS, Inc. (formerly DfR 

Solutions, Inc.) to estimate the expected 

lifespans of CO/combustion sensors 

while operating in a gas furnace or 

boiler application. The report titled 

‘‘Performance and Accelerated Life 

Testing of Carbon Monoxide and 

Combustion Sensors,’’ dated May 28, 

2019, is included as attachment 1 of Tab 

C of the Staff NPR Briefing Package. The 

report titled ‘‘Performance and 

Accelerated Life Testing of Redesigned 

Carbon Monoxide and Combustion Gas 

Sensors,’’ dated February 25, 2022, is 

included as attachment 2 of Tab C of the 

Staff NPR Briefing Package. The ANSYS 

report demonstrated that CO/ 

combustion sensors are currently 

commercially available for use in gas 

appliances; the CO/combustion sensors 

that were tested had expected lifespans 

ranging from 6.4 to 10 years operating 

under conditions that replicate the main 

stress conditions expected within a gas 

appliance. 

B. Justification for Proposed 

Performance Requirements 

The proposed performance 

requirements are reasonably necessary 

and feasible for the following reasons: 

• The gas furnaces and boilers under 

consideration are associated with an 

estimated 21 deaths per year, on average 

(2017–2019), and an estimated total of 

539 CO deaths from 2000 to 2019; 

• the existing voluntary standards do 

not include provisions that would 

protect consumers from a number of 

conditions described in section IV of the 

preamble that are known to cause or 

contribute to the production, leakage 

into, and accumulation of dangerous 

concentrations of CO in the living space 

of a dwelling; 

• there is no indication that the Z21/ 

83 Technical Committee or any of the 

technical Subcommittees for gas 

furnaces and boilers intend to address 

this hazard; and 

• continuous monitoring of the 

combustion process or the concentration 

of carbon monoxide within the 

combustion gases can be accomplished 

using commercially available CO/ 

combustion sensing or combustion 

control technology. 

The proposed performance 

requirements described in this section 

of the preamble are intended to reduce 

the occurrence of CO-related deaths, 

injuries, and exposures associated with 

gas furnaces and boilers. Specifically, 

gas furnaces and boilers would 

continuously monitor CO emissions and 

shut down or modulate combustion if 

any of the average CO ranges specified 

in Table 1 7 are detected in the gas 

furnaces and boilers flue gases for the 

durations listed. 

TABLE 1—CO RANGES AND DURATIONS FOR SHUT-DOWN OR MODULATION

Average CO 

(ppm) 

Duration 

(minutes) 

500 or above .............................. 15 

400–499 ...................................... 30 

300–399 ...................................... 40 

200–299 ...................................... 50 

150–199 ...................................... 60 

The average CO ranges in Table 1 are 

the proposed setpoints and durations at 

which a gas furnace or boiler must 

either shut down or begin modulation. 

These CO ranges are based on Curve G 

of the CO Concentration vs. Time graph 


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Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 73279 

(Figure 41.1 from UL 2034) in Figure 8 

which indicates what an individual’s 

carboxyhemoglobin (COHb) levels 

would be if exposed to various CO 

concentrations and the time of exposure 

needed to reach that COHb level. Curve 

G represents a 20 percent COHb level 

and the onset of health effects in 

individuals (i.e., a headache). The 

values on the y-axis represent CO 

exposure levels in parts per million 

(ppm) from zero ppm CO to 1,800 ppm 

CO. The values on the x-axis represents 

the time durations (in minutes) of 

exposure to the CO concentrations 

presented on the y-axis. The curves A 

through J on the graph represent the 

various carboxyhemoglobin levels an 

individual can reach when exposed to 

CO (y-axis) over a period of time (xaxis). 

To interpret the graph in Figure 8, 

begin at a given CO concentration on the 

y-axis and extend a horizontal line to 

the right until the line intersects a COHb 

curve. At the point of intersection, 

extend a vertical line downwards to the 

x-axis. The time value at this point of 

intersection represents the amount of 

time, at the selected CO concentration, 

at which an individual would reach a 

certain COHb level. For example, at a 

400 ppm CO concentration, it would 

take approximately 35 minutes for an 

individual to reach a COHb of 20 

percent. At a CO concentration of 300 

ppm, it would take approximately 50 

minutes to reach a COHb of 20 percent. 

The dots on the graph in Figure 8 

illustrate that the entire proposed CO 

response range (i.e., 150–400 and above) 

all fall on Curve G. A performance 

requirement that requires shutdown or 

modulation of a gas furnace or boiler at 

this range of CO levels provides 

protection to consumers from the onset 

of the more serious CO-related health 

effects, such as vomiting, coma, and 

death. The proposed performance 

requirement for the range and time 

period for CO exposure is consistent 

with the existing UL 2034 standard for 

consumer carbon monoxide alarms, 

which uses similar requirements to 

protect consumers from CO exposure in 

the home. 

Manufacturers may comply with the 

performance requirements under the 

proposed rule by using an option for 

either shut down or modulation of the 

gas furnace or boiler if the average CO 

level reaches 150 ppm over a 15-minute 

duration. This option simplifies the 

performance requirement to a single CO 

setpoint rather than multiple setpoints 

as described above. It provides the same 

level of protection as the multiple 

setpoint approach described above 

because the gas furnace or boiler would 

be required to shut down or modulate 

at the lowest threshold of CO 

production (150 ppm) that can result in 

low-level health effects (i.e., headache 

per the 20 percent COHb curve). The 

shorter time duration (15 minutes) is 

protective at higher CO concentrations 

of 200 ppm or more that can begin to 

cause the onset of health effects (i.e., a 

headache per the 20 percent COHb 

curve). 

The proposed performance 

requirements described in section VIII 

of the preamble are also based, in part 

on, on the definitions and performance 

requirements in ANSI Z21.47, Standard 

for Gas-fired central furnaces; ANSI 

Z21.13, Standard for Gas-fired low 

pressure steam and hot water boilers, 

and ANSI Z21.86, Standard for Vented 

gas-fired space heating appliances, as 


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73280 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

8EN 15502–2–1, Gas-fired central heating boilers, 

Part 2–1: Specific standard for type C appliances 

and Type B2, B3 and B5 appliances of a nominal 

heat input not exceeding 1,000 kW. 

9EN 15502–2–2, Gas-fired central heating boilers 

Part 2–2: Specific standard for type B 1 appliances. 

10BS EN 13611, Safety and control devices for 

burners and appliances burning gaseous and/or 

liquid fuels—General requirements. 

11BS EN 16340, Safety and control devices for 

burners and appliances burning gaseous or liquid 

fuels—Combustion product sensing devices. 

12 Gas/air ratio controls for gas burners and gas 

burning appliances—Part 2: Electronic types 

13 JIS–S–2109, Gas burning water heaters for 

domestic use. 

14 JIS–S–2112. Gas hydronic heating appliances 

for domestic use. 

15 JIS–S–2122, Gas burning space heaters for 

domestic use. 

well as performance requirements from 

CEN 8 9 standards for domestic gas 

boilers, and CEN standards for safety 

and control devices for gas 

appliances 10 11 and gas/air ratio controls 

for gas appliances,12 and JIS standard 

for domestic gas water heaters, boilers 

and space heaters.13 14 15 The CEN and 

JIS standards were given weight when 

developing the proposed performance 

requirements because the provisions in 

these standards are similar to the 

proposed performance requirements for 

gas furnaces and boilers in this NPR and 

are readily applicable to U.S. gas 

furnaces and boilers. In addition, 

although there are significant 

differences between the design 

platforms of European and Japanese gas 

boilers (i.e., predominantly premix 

power burner designs) and U.S. gas 

furnaces and boilers (i.e., predominantly 

induced draft and some atmospheric 

vent designs), the basic operating 

environment parameters (e.g., 

temperature, humidity, and combustion 

gases) within the heat exchangers and 

flues of European and Japanese gas 

boilers and U.S. gas furnaces and boilers 

are similar. The European and Japanese 

circumstances demonstrate the 

commercial availability of CO/ 

combustion sensors and combustion 

controls that: (1) provide CO/ 

combustion sensor-based shutoff or 

reduced CO through combustion 

control; (2) are durable enough to 

survive in heat exchangers or flues of 

gas appliances; and (3) can be applied 

for use in U.S. gas furnaces and boilers. 

The proposed rule provides test 

methods to introduce a simulated 400 

ppm, 300 ppm, 200 ppm, and 150 ppm 

CO emission level into the exhaust gas 

to determine if the safety system passes 

or fails the proposed performance 

requirements. 

As explained in Tab B of the Staff 

NPR Briefing Package, staff assesses that 

the proposed rule would be 90 to 100 

percent effective in preventing CO 

deaths and injuries associated with gas 

furnaces and boilers, because CO 

production at the gas furnace and boiler 

would be limited to levels that produce 

a headache in exposed consumers. 

Staff’s assessment is based on the 

following key metrics used to assess the 

capability of the performance 

requirement in protecting consumers 

from the identified CO exposure risks: 

• Detecting CO at the source of 

production: This provides a greater level 

of protection to consumers than 

residential CO alarms because it detects 

CO at the source of production within 

the gas furnace or boiler, before it leaks 

into a dwelling space, and allows for an 

earlier response time to protect 

consumers. 

• Prevents or limits production of 

harmful levels of CO: Shutoff or 

modulation of the gas furnace or boiler 

directly addresses harmful CO 

production. 

• Selecting CO response 

concentrations that fall on the 20 

Percent COHb curve: Selecting multiple 

CO response concentrations or a single, 

threshold CO concentration (150 ppm or 

higher) limits the severity of any 

potential health effects to a headache 

(i.e., the 20 percent COHb curve). 

• Addresses all known hazard 

patterns: Although the performance 

requirements do not prevent 

combustion product (including CO) 

leakage, the requirements do protect 

against serious harm from leakage of 

combustion products by limiting/ 

preventing CO production. 

VII. Response to Comments 

In response to the Commission’s 2019 

ANPR regarding residential gas furnaces 

and boilers, CPSC received 15 

comments from the public, divided 

between supporters and opponents of 

the proposal. Opposing comments came 

primarily from the gas appliance 

industry. The comments can be found 

under docket number CPSC–2019–0020, 

at: www.regulations.gov. Below is 

summary of the comments and CPSC’s 

responses by topic area. 

Alternatives to Performance 

Requirements 

Comment: Nine commenters (A.O 

Smith, Carrier, Crown, Rheem, US 

Boiler Co. Edward Johan (USBC EJ), US 

Boiler Co. John Busse (USBC JB), Air 

Conditioning, Heating, and Refrigeration 

Institute (AHRI), Strauch, and Stanonik) 

asserted that rulemaking is not 

necessary because residential CO alarms 

will prevent CO poisoning from gas 

appliances. One commenter (Stanonik) 

further claimed that information from 

CPSC’s IDI reports show that CO alarms 

are effective in protecting participants 

from exposure to hazardous levels of CO 

and that a survey being conducted by 

CPSC should be completed before 

rulemaking occurs. Four commenters 

(Crown, USBC EJ, USBC JB, and AHRI) 

supported changing the ANSI gas 

appliance standards and/or building 

codes to require CO alarm installation. 

Response: CPSC lacks statutory 

authority to mandate that consumers 

install CO alarms in their homes. 

Although the Commission urges use of 

residential CO alarms, not all homes are 

equipped with functioning and 

maintained CO alarms, and fewer still 

have them in all occupied spaces into 

which CO may leak from a gas furnace 

or boiler. Despite CPSC, state and local 

governments, and the private section 

information and education campaigns to 

increase the use of CO alarms, injuries 

and fatalities that occur annually are 

evidence that this hazard continues to 

kill and injure consumers, supporting 

the view that effective performance 

requirements for gas appliances are 

critical to consumer safety. 

Comment: USBC JB stated that a CO 

monitor in the equipment room or living 

space would provide a better solution 

than a CO monitor on the appliance. 

Response: A monitoring system 

located within the equipment room or 

living space would not necessarily 

detect CO at all foreseeable points of 

potential leakage along the length of the 

vent system. In contrast, detecting 

excessive CO leakage at the point of 

production on the appliance would 

protect consumers from CO exposure, 

regardless of the point or mechanism of 

leakage, or the cause of elevated CO 

production. 

Comment: USBC JB stated that CPSC 

should sponsor and provide funding for 

a multi-functional task force to develop 

solutions to reduce and eliminate CO 

poisoning caused by residential gas 

furnaces and boilers. 

Response: CPSC has contributed 

extensively to the development of 

proposed solutions to the CO hazard 

from gas furnaces and boilers. Staff’s 

memorandum in Tab D of the Staff 

ANPR Briefing Package summarizes 

CPSC staff’s efforts from 2000 to 2019 to 

work with the ANSI Z21/T83 Technical 

Committee to address carbon monoxide 

poisoning that was continuing to occur 

despite revisions to the gas appliance 

standards. CPSC staff conducted 

research and shared the results of that 

research, along with incident reports, 

with the Committee. Staff also 

submitted two proposals to the 

Technical Committee (in 2000 and 

2015) requesting that the relevant 

voluntary standards add requirements to 


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address the production of hazardous 

levels of CO and the risk of that CO 

entering the living space of a dwelling. 

Despite staff’s efforts over two decades, 

as well as the developments of 

voluntary standard requirements in 

Japan and Europe, the U.S. voluntary 

standards community has not 

adequately addressed the CO risk at the 

source of production in gas appliances. 

Indeed, in 2019 the Technical 

Committee disbanded the working 

group assessing possible revisions to the 

standards. 

Comment: USBC JB predicted that gas 

furnaces and boilers will eventually be 

replaced with electric heating 

appliances because current and future 

efforts to reduce carbon emissions will 

eliminate or restrict the availability of 

natural gas for residential appliances. 

Response: Gas appliances and boilers 

continue to be sold in large numbers for 

residential heating in the United States, 

without an effective voluntary solution 

to the CO hazard. Therefore, the 

Commission preliminarily concludes 

that mandatory performance 

requirements to address CO production 

by gas furnaces and boilers are 

necessary to reduce deaths and injuries 

from CO exposure that otherwise will 

continue to occur. 

Comment: USBC JB referred to 

periodic inspection and service of gas 

appliances and asked if CPSC’s data 

addresses whether ‘‘formalized 

inspection and service requirements 

would reduce carbon monoxide 

poisoning.’’ Two other commenters 

(Crown and AHRI) asserted that a formal 

program to check installation, service, 

and maintenance will reduce carbon 

monoxide incidents. 

Response: CPSC lacks statutory 

authority to mandate homeowners’ 

spending for maintenance services. 

Further, CPSC staff is not aware of data 

indicating that maintenance alone can 

address the deadly CO hazard from gas 

furnaces and boilers. Manufacturers 

already recommend routine 

maintenance of furnaces and boilers, yet 

injuries and deaths continue to occur for 

the reasons described above. 

Comment: Crown and USBC JB 

asserted that CPSC should rely on 

recalls to prevent/reduce CO incidents 

involving gas boilers and furnaces. 

Response: When a product is subject 

to a CPSC recall, the product already 

may have been involved in an incident, 

in this case a CO exposure incident that 

may have caused serious injury or 

death. The CPSC will continue to utilize 

the CPSA section 15 recall process, 

independent of this this rulemaking, but 

it is not a substitute for the proposed 

rule, which addresses elevated CO 

levels that may be unrelated to a defect 

in the furnace or boiler itself. 

Rely on Consumer or Installer Education 

Comment: Carrier, Crown, Rheem, 

USBC EJ, and USBC JB stated that 

information and education programs for 

consumers, installers, and maintenance 

personnel will adequately address CO 

poisoning hazards. 

Response: Information and education 

campaigns currently exist, and yet 

numerous deaths and injuries continue 

to occur due to CO poisoning from gas 

furnaces and boilers demonstrating that 

these campaigns do not adequately 

address the hazard. 

Warnings rely on educating 

consumers about the hazard and 

persuading consumers to alter their 

behavior in some way to avoid the 

hazard. To be effective, warnings also 

depend on consumers noticing or 

otherwise receiving the message, 

attending to the message, remembering 

the recommended behaviors when 

needed, and behaving consistently, 

regardless of situational or contextual 

factors that influence precautionary 

behavior, such as fatigue, stress, or 

social influences. Thus, providing 

warnings and instructions about hazards 

is less effective than either designing the 

hazard out of a product or guarding the 

consumer from the hazard. 

Rely on Voluntary Standards 

Comment: Commenters A.O. Smith, 

Rheem and the National Propane Gas 

Association (NPGA) stated that the 

CPSC should work with voluntary 

standards organizations to address the 

hazard. 

Response: Tab D of the Staff ANPR 

Briefing Package summarizes CPSC 

staff’s efforts from 2000 to 2019 to work 

with the ANSI Z21/T83 Technical 

Committee to address carbon monoxide 

poisoning incidents. As described 

above, despite staff’s efforts, the 

voluntary standards organizations have 

not adopted adequate performance 

requirements to address the hazard. 

Comment: Carrier and AHRI noted 

that current appliance designs certified 

to the applicable ANSI/CSA Z21 safety 

standards already incorporate several 

safety features that reduce the risk of 

carbon monoxide production. These 

include blocked vent/intake switches, 

draft hood spill switches, and flame 

roll-out switches. Another commenter 

(USBC JB) stated that the ANSI standard 

for direct and non-direct vent boilers 

includes a test method to limit CO 

levels when the flue outlet is blocked or 

partially blocked, which USBC JB 

believes addresses the impact of snow 

blocking the vent. Stanonik stated that 

two-pipe or direct vent systems have 

fewer CO risks and some 

atmospherically vented appliances are 

not susceptible to depressurizing and 

back drafting that lead to CO exposure 

in the living space, and that these 

features, combined with the proper 

installation, service, and maintenance of 

the appliances, would eliminate the CO 

risk. 

Response: Blocked vent/intake 

pressure switches, draft hood spill 

switches, and flame rollout switches are 

all requirements that were added to and 

became effective in the standards 

between 1987 and 1993. Yet injuries 

and deaths from CO poisoning have 

continued to occur despite the existence 

of these voluntary standards provisions. 

Indeed, as discussed in Tab B of the 

Staff NPR Briefing Package, the 

particular voluntary standards 

provisions cited by these commenters 

have failed to prevent deaths and 

injuries in real-world scenarios. 

Adverse/Unintended Consequences of 

Shut-Off Triggered by CO Sensor 

Comment: Six commenters (Carrier, 

Crown, USBC EJ, USG JB, AHRI, and 

Strauch) stated that improper shutdown of a gas appliance by a CO sensor 

will cause a no-heat hazard for 

consumers. 

Response: In response to these 

comments and other staff analyses, the 

proposed rule would require a fail-safe 

provision that would operate for the life 

of the appliance. If a CO sensor, 

combustion sensor, combustion control 

system, or other device designed to meet 

these requirements, fails to operate 

properly or at all, then the appliance 

shall shutdown and restart after 15 

minutes, repeating this cycle and 

continuing to provide heat until the 

failed component is replaced, while also 

alerting the consumer of the hazard. For 

the life of the gas furnace or boiler, the 

proposed fail-safe provision would be 

required to notify consumers and 

service technicians of device failure by 

either a flashing light, or other 

appropriate code on the appliance 

control board, that corresponds to the 

device failure. 

Comment: Crown stated that a shutdown central heating appliance may 

encourage the use of less safe heating 

alternatives. 

Response: Shut-off devices on gas 

furnaces and boilers (e.g., BVSS, flame 

rollout switches, and over temperature 

limit switches) have been required by 

the ANSI Z21 standards for 25 to 30 

years. However, we are not aware of any 

trends of consumers using less safe 

heating alternatives as the result of these 

other safety shut-down devices on these 


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products. Furthermore, the proposed 

rule has a fail-safe provision, as 

described above, which provides 

warning to consumers of a CO sensor 

issue without complete loss of 

functionality of the gas furnace or 

boiler. 

Carbon Monoxide Sensor—Sensitivity 

and Durability 

Comment: American Gas Association 

(AGA) and USBC JB asserted that 

measuring ‘‘air-free’’ CO concentrations 

benchmarked to the ANSI-recognized 

‘‘safe’’ concentration of 400 ppm would 

be complex because a carbon monoxide 

monitor measures ‘‘raw’’ CO 

concentrations which includes the ‘‘airfree’’ carbon monoxide concentration 

multiplied by the ratio of air that was 

not used in combustion. Consequently, 

the air-free CO will always be lower 

than the measured CO. 

Response: CPSC staff agrees that an 

air-free measurement calculation would 

be more complex since it would require 

the measurement of carbon dioxide or 

oxygen as well, and the proposed rule 

does not require this calculation. 

Comment: USBC JB stated that the 

performance of existing CO sensors has 

not been established at the 400 ppm 

level and lower. 

Response: In general, sensor 

manufacturers specify the maximum 

and minimum concentration range that 

a sensor can detect, as well as whether 

the sensor provides a linear output 

voltage in response to the gas (i.e., CO) 

it’s designed to detect. For example, if 

a manufacturer specifies that their 

sensor has a linear response range of 0 

to 10,000 ppm of CO, then the sensor 

can detect between 0 and 10,000 ppm 

CO, including 400 ppm CO or lower. 

CPSC staff has identified multiple CO 

sensors with an advertised linear 

response range that extends below 400 

ppm. 

Comment: Strauch asserted that 

research does not show that CO sensors 

are durable enough to last for 15 to 20 

years. Another (USBC JB) stated that 

performance requirements normally 

address device tolerances to allow 

conformance at prescribed conditions 

and avoid nuisance issues. 

Response: We do not agree with the 

premise that CO sensors must have a 15- 

to-20 year lifespan in order for the 

proposed rule to be effective. Many 

parts may fail during the lifetime of a 

gas furnace or boiler, resulting in the 

need for replacement or a service call to 

fix or replace the part. CO sensors 

would be expected to be treated in this 

same manner as other parts that need to 

be replaced during the lifespan of the 

product. The costs of such services are 

included in the preliminary regulatory 

analysis in section IX of the preamble. 

Regarding the comment about 

tolerances, manufacturers will need to 

select appropriate sensors and other 

equipment to ensure that their furnaces 

and boilers comply with the proposed 

standard. 

Requirements in International 

Standards 

Comment: Crown and USBC JB 

asserted that there is no widespread use 

of CO sensors in gas appliances in 

Europe and Japan. One commenter 

(AHRI) observed that ‘‘the EN standards 

(EN 15502–1, EN 15502–2–1 and EN 

15502–2–2) do not require 

manufacturers to incorporate a COsensor shut-off device within the 

appliance.’’ In addition, that commenter 

stated none of the U.S. or international 

standards, including JIS S 2019, 

specifically require a CO sensor within 

the appliance. AHRI stated that the most 

commonly used CO sensor, 

manufactured by Nemoto Sensor 

Engineering, Ltd., is designed to work 

when carbon monoxide levels exceed 

1000 ppm. 

Response: While the Japanese 

standard, JIS S 2019, and the European 

standards, EN 15502–2–1 and EN 

15502–2–2, do not specifically require a 

CO sensor in-situ (i.e., within the heater 

exchanger or flue passage ways of the 

appliance), each standard includes an 

option that allows for CO and 

combustion sensors in-situ if the 

manufacturer chooses to use that 

approach to meet the requirements of 

the respective standards. Some 

European and Japanese gas boilers 

products certified to those standards are 

equipped with CO sensor shutoff 

capability. More generally, the existence 

of the option to use CO sensors 

incorporated in-situ to meet the 

requirements of respective standards 

reinforces that such sensors are feasible. 

Regarding Nemoto sensors, the 

published Nemoto product literature 

(https://sensor.nemoto.co.jp/en/ 

product/detail/nap-78su/) indicates that 

the CO sensors in question have a linear 

response range of zero to 10,000 ppm 

CO; thus the sensors in question are 

represented by Nemoto to have the 

capability to provide an output voltage 

response to all of the CO levels within 

that range, including 400 ppm CO and 

lower. 

Feasibility of Performance Requirements 

With Existing CO/Combustion 

Technology 

Comment: Carrier and AHRI stated 

that ‘‘a minimum of 20 years is needed 

to replace existing residential gas 

appliances with a carbon monoxide 

sensor-equipped appliances’’ based on 

the anticipated lifespan of an appliance. 

USBC JB stated that it would take a 

minimum of two to three years to 

develop and validate performance 

requirements and then revise the 

voluntary standards through the 

consensus process. 

Response: We agree that it will take 

time for existing gas furnaces and 

boilers to be replaced by newly installed 

equipment that meets the requirements 

of the proposed rule mandating 

additional safety features for future gas 

furnaces and boilers; inasmuch as the 

proposed rule does not require 

replacement of existing installed gas 

furnaces and boilers and would only 

apply to the future manufacture of gas 

furnaces and boilers. This is reflected in 

the preliminary regulatory analysis in 

Section IX of the preamble. 

Approximately two million gas furnaces 

and 800,000 gas boilers without CO 

sensors are sold each year, thus 

prolonging the time it would take to 

replace old stock. As a result, each year 

of further delay in instituting safety 

features to address the CO hazard will 

result in millions of units without these 

features being sold and installed and 

remaining in homes for multiple 

decades, risking additional preventable 

deaths and injuries. 

Comment: Carrier and AHRI stated 

that CO sensors will not detect leakage 

from the venting system. 

Response: The proposed rule focuses 

on the source rather than leakage points 

throughout the exhaust path because of 

the extent, variability, and potential 

inaccessibility of the exhaust path in 

homes. We agree that a CO sensor will 

not detect leakage from a venting 

system. However, CO detection at the 

source of production would provide 

protection to consumers regardless of 

the location of downstream leakage. For 

these reasons, we disagree with AHRI’s 

assertion that a CO sensor-equipped 

appliance would be ineffective against a 

compromised vent. 

Comment: A.O. Smith stated that CO 

sensors in a gas appliance cannot easily 

be replaced in the field. 

Response: The commenter provided 

no technical evidence to support the 

claim that CO sensors cannot be 

installed so that they are easily replaced 

in the field. CPSC staff is aware of and 

has access to gas appliances that utilize 

CO sensors, air/fuel ratio sensors, and 

other combustion control devices within 

the combustion chamber of flue 

passageways to provide CO safety and/ 

or energy efficiency. CO sensors are no 

more complex and do not present any 

greater difficulty in gaining access to the 


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devices for maintenance or replacement 

than other safety devices, such as 

pressure switches, flame sensors, and 

flame rollout switches, currently 

required by the ANSI standards for gas 

appliances. Sensors are comprised of a 

sensing element covered by shielding 

and a mounting flange. Typically, the 

shielded, sensing element is inserted 

through an access hole through the 

bulkhead of a combustion chamber, 

plenum, or flue passageway. The sensor 

is generally mounted to the bulkhead 

with two screws with a heat-resistant 

gasket between the mounting flange and 

the bulkhead. We assess that CO sensors 

in a gas appliance could be replaced in 

consumer homes in a manner similar to 

other existing gas furnace or boiler 

components that are currently serviced 

and replaced in consumer homes. 

Comment: Rheem asserted that some 

of the referenced/observed failure 

modes in the ANPR cannot be addressed 

through appliance design alone. 

Response: We do not agree with the 

assertion that failure mode issues 

cannot be addressed through appliance 

design. By ensuring that harmful levels 

of CO are not produced in the gas 

furnace or boiler, the proposed 

requirements remove the need to 

provide protection throughout the entire 

exhaust vent system. 

Comment: Stanonik stated that the 

document ‘‘Findings from CPSC’s 2014 

Carbon Monoxide/Combustion Sensor 

Forum and Request for Information’’ 

(https://www.cpsc.gov/s3fs-public/pdfs/ 

blk_pdf_Findings-from-the-FY14- 

Sensor-Forum-and-RFI.pdf) indicates 

that a specific sensor technology that 

appeared to address durability and 

longevity concerns is very expensive 

and reflected the ‘‘significant process’’ 

involved in developing durable and 

reliable sensor products. 

Response: We agree that the cost the 

commenter referenced would be high. 

However, the sensing technology in 

question was an evaluation unit, not a 

full-scale production unit, and came 

with electronic controls necessary to 

operate and evaluate the sensor, 

resulting in elevated costs for that 

particular sensing technology. The cost 

per unit typically goes down with largescale production. CPSC staff estimates 

costs for volume purchases in the range 

of approximately $5 to $15 per unit. The 

preliminary regulatory analysis in 

section IX of the preamble provides 

further analysis of potential costs and 

benefits. 

VIII. Description of the Proposed Rule 

The proposed rule would create a new 

part 1408, ‘‘Safety Standard for 

Residential Gas Furnaces and Boilers.’’ 

The provisions of the proposed rule are 

described below. 

A. Proposed Section 1408.1 Scope, 

Purpose, and Effective Date 

Proposed section 1408.1 provides that 

new part 1408 establishes a consumer 

product safety standard that would 

provide performance requirements for 

residential gas furnaces and boilers that 

are consumer products used to heat 

dwellings. The purpose of these 

requirements is to reduce the 

occurrence of carbon monoxide-related 

deaths, injuries, and exposures 

associated with gas furnaces, boilers, 

and wall and floor furnaces. All 

requirements of the proposed rule apply 

to all residential gas furnaces, boilers, 

and wall and floor furnaces that are 

manufactured after the proposed 

effective date, which is 18 months after 

publication of the final rule in the 

Federal Register. 

B. Proposed Section 1408.2 Definitions 

Proposed section 1408.2 provides 

definitions that apply for purposes of 

part 1408. Proposed section1408.2 

provides definitions for the covered 

categories of furnaces and boilers. The 

proposed definitions are based on the 

definitions used in ANSI Z21.47–2021, 

ANSI Z21.13–2022, and ANSI Z21.86– 

2016 for the same product types. 

C. Proposed Section 1408.3

Performance Requirements for Gas 

Furnaces and Boilers 

Proposed section 1408.3 provides 

general requirements, performance 

requirements, test configuration, and 

test methods for all residential gas 

furnaces and boilers. Section VII.B of 

the preamble provides the technical 

justification for these proposed 

requirements. 

1. Proposed Section 1408.3(a) (General 

Requirements) 

Proposed section 1408.3(a) provides 

that all residential gas furnaces and 

boilers must have a means to either 

directly or indirectly monitor the 

concentration of carbon monoxide 

produced during the combustion 

process and shut down or modulate 

combustion to reduce average CO 

concentrations to below the CO levels 

for the durations of time specified in 

proposed section 1408.3(b). The gas 

furnace or boiler must either shut down 

or modulate combustion to reduce 

average CO emissions to below 150 ppm 

if the average CO emissions reach or 

exceed the CO limits and time durations 

specified in section 1408.3(b). 

Proposed section 1408.3(a) also states 

that indirect monitoring and control of 

CO emissions can be accomplished by 

monitoring and controlling other 

combustion parameter(s) that accurately 

correlate to the production of CO. 

Proposed section 1408.3(a) provides 

examples of parameters that can serve as 

a proxy for CO production such as 

carbon dioxide (CO2), oxygen (O2), the 

Gas/Air Ratio, and the flame ionization 

current produced by the burner flame. 

2. Proposed Section 1408.3(b) 

(Performance Requirements) 

Proposed section 1408.3(b) provides a 

performance requirement that a gas 

furnace or boiler must be equipped with 

a means to continuously monitor CO 

emission and must meet the 

requirements described in either 

proposed section 1408.3(b)(1) or (b)(2) 

(direct means to monitor CO emissions) 

or (b)(3) or (4) (indirect means to 

monitor CO emissions) when tested 

using the test method described in 

proposed section 1408.3(d). Proposed 

paragraphs 1408.3(b)(1) and (2) provides 

two options for gas furnaces and boilers 

manufacturers to use direct means to 

monitor CO emissions that must cause 

either shut-down or modulation of the 

gas furnace or boiler combustion, based 

on conditions within the gas furnace or 

boiler for a range of specified average 

CO concentrations for the specified time 

frames. Proposed section 1408.3(b)(3) 

provides two options for gas furnace 

and boiler manufacturers to use an 

indirect means to monitor CO emissions 

that must either cause shut-down of the 

gas furnace or boiler or cause 

modulation of combustion of the gas 

furnace or boiler, based on conditions 

within the gas furnace or boiler for a 

range of specified average CO 

concentrations for the specified time 

frames described. 

Proposed section 1408.3(b)(4) 

provides a fail-safe requirement that 

during the life of the gas furnace or 

boiler, if a CO sensor, combustion 

sensor, combustion control system, or 

other device designed to meet these 

requirements fails to operate properly or 

at all, then the gas furnace or boiler 

must shutdown and restart after 15 

minutes and repeat this cycle until the 

failed component is replaced. The 

requirement mandates that consumers 

and service technicians must be notified 

of device failure by either a flashing 

light, or other appropriate code on the 

gas furnace or boiler control board, that 

corresponds to the device failure. 

3. Proposed Section 1408.3(c) (Test 

Configuration) 

Proposed section 1408.3(c) describes 

the requirements that gas furnace or 

boilers must be configured in 


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accordance with the provisions of the 

combustion sections of the respective 

voluntary standards (section 5.8.1 of 

ANSI Z21.47–2021 for gas furnaces; 

section 5.5.1 of ANSI Z21.13–2022 for 

gas boilers; and sections 9.3.1, 11.2.1, 

and 13.3.1, of ANSI Z21.86–2016 for gas 

wall and floor furnaces) with respective 

instruction on how products are to be 

configured before testing to proposed 

section 1408.3(d). 

4. Proposed Section 1408.3(d) (Test 

Procedure) 

Proposed section 1408.3(d) provides 

the test procedure to be used to test a 

gas furnace or boiler after the product 

has been configured pursuant to 

proposed section 1408.3(b) to 

demonstrate compliance with the 

performance requirements provided in 

proposed section 1408.3(b). 

D. Proposed Section 1408.4

Incorporation by Reference 

Proposed section 1408.4 incorporates 

by reference ANSI Z21.47–2021, ANSI 

Z21.13–2022, and ANSI Z21.86–2016 

regarding the test setup cited in 

proposed section 1408.3 and provides 

information on where the standards are 

available. 

E. Proposed Section 1408.5 Prohibited 

Stockpiling 

Pursuant to section 9(g)(2) of the 

CPSA, 15 U.S.C. 2058(g)(2), the 

proposed rule would prohibit a 

manufacturer from ‘‘stockpiling’’ or 

substantially increasing the manufacture 

or importation of noncompliant gas 

furnaces and boilers between the date 

publication of the final rule and the 

effective date. The provision, which is 

explained more fully in Tab D of the 

Staff NPR Briefing Package, would 

prohibit the manufacture or importation 

of noncompliant products at a rate that 

is greater than 106 percent of the base 

period in the first 12 months after 

promulgation, and 112.50 percent of the 

base period for the duration of 12 

months after promulgation until the 

effective date. The base period is 

defined in the proposed rule as the 

calendar month with the median 

manufacturing volume, among months 

with manufacturing volume, during the 

last 13 months prior to the rule’s 

publication. 

We propose a rate of 106 percent for 

the first 12 months and a rate 112.50 

percent in the final 6 months between 

publication and effective date based on 

the historical growth of the industry. We 

propose a higher rate of 112.50 percent 

for the second year to account for the 

baseline growth of the industry in the 

second year. 

Individual manufacturers may 

experience growth rates outside the 

historical range. Shipment data for gas 

furnaces and boilers show a steady, yet 

seasonal, market. Shipments of gas 

furnaces and boilers begin to rise in 

March and continuously increase until 

December, after which they fall off 

sharply. The Commission seeks public 

comment on manufacturing, the 

seasonality of sales, and supply chain of 

gas furnaces and boilers to further 

understand these topics. 

F. Appendix A to Part 1408—Findings 

Under the Consumer Product Safety Act 

The findings required by section 9 of 

the CPSA are discussed throughout this 

preamble and set forth in Appendix A 

to the proposed rule. 

IX. Preliminary Regulatory Analysis 

Pursuant to section 9(c) of the CPSA, 

publication of a proposed rule must 

include a preliminary regulatory 

analysis containing: 

• A preliminary description of the 

potential benefits and potential costs of 

the proposed rule, including any 

benefits or costs that cannot be 

quantified in monetary terms, and an 

identification of those likely to receive 

the benefits and bear the costs; 

• a discussion of why a relevant 

voluntary safety standard would not 

eliminate or adequately reduce the risk 

of injury addressed by the proposed 

rule; and 

• a description of any reasonable 

alternatives to the proposed rule, 

together with a summary description of 

their potential costs and benefits and 

why such alternatives should not be 

published as a proposed rule. 

This preamble contains a summary of 

the preliminary regulatory analysis for 

the proposed rule. Tab D of the Staff 

NPR Briefing Package contains a 

detailed analysis. 

A. Market Information 

1. The Product 

Gas furnaces and boilers are vented 

gas heating appliances that heat 

residential dwellings. Section III of the 

preamble provides a detailed discussion 

of the nature and operation of gas 

furnaces and boilers. The average 

product life for gas furnaces and boilers 

ranges from approximately 22 to 25 

years. 

Gas furnaces and boilers include 

central warm-air furnaces and boilers as 

well as floor, and wall furnaces. 

• Central warm-air furnaces and 

boilers use a central combustor, or 

boiler, to heat air using natural gas, and 

liquid propane. Some of these furnaces 

move the heated air using a blower or 

fan through ducts while others rely on 

the natural flow of warm air going up 

and cold air down to circulate air. Most 

boilers supply steam or hot water 

through conventional radiators or 

baseboard radiators. 

• Floor and wall furnaces are less 

common than central furnaces and 

boilers and consist of ductless 

combustors to heat air. A floor furnace 

and wall furnace heat the physical parts 

of the house (i.e., floor or wall) to heat 

the dwelling. A furnace is typically 

located in a basement and delivers 

heated air through a large register in the 

floor above it. 

Consumers purchase gas furnaces and 

boilers primarily through contract 

installers, but they may also purchase 

units at retail stores and online retailers. 

CPSC staff estimate the average retail 

price of gas furnaces to be $1,660 and 

$3,719 for gas boilers. 

2. Market Trends for Gas Furnaces and 

Boilers 

Staff identified as many as 70 firms 

that manufacture or import residential 

gas furnaces and boilers. When 

accounting for subsidiaries and multiple 

brands provided by the same company, 

staff identified 20 parent firms. In 2016, 

the largest 10 firms by revenue 

accounted for 83.3 percent of heating 

equipment sales. Seven of these firms 

are based in the U.S. 

Department of Energy’s (DOE) most 

recent Residential Energy Consumption 

Survey (RECS) reports the total number 

of gas furnaces, gas boilers, and wall 

furnaces in-use to be 60.94 million in 

2020. This is an increase from 57.90 

million in 2015. Between 2015 and 

2020, therefore, the number of in-scope 

gas furnaces and boilers grew at an 

average annual rate of 1.03 percent. 

DOE’s Government Regulatory Impact 

Model (GRIM) projects gas furnace sales 

in 2021 to be 3.58 million units and gas 

boilers to be 0.30 million units. CPSC 

staff estimated that residential gas 

furnaces and boilers sales in 2021 to be 

$5.94 billion and $1.12 billion, 

respectively. 

CPSC staff estimate that residential 

gas boiler imports average $117.67 

million annually. The Commission 

requests comment on the value and 

quantity of gas furnaces and boilers 

imports that would be subject to a 

proposed rule. 

3. Future Market Size for Gas Furnaces 

and Boilers 

Staff used a 1.03 percent annual 

growth rate derived from DOE’s GRIM to 

project sales into the future. Using this 

approach, staff estimates the number of 


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16 Deadweight loss is the value of lost transactions 

that may occur after major market events such as 

a new regulation. 

17Staff uses a discount rate to incorporate the 

time value of money during the 30-year study 

period. In the analysis, staff presents both costs and 

benefits in undiscounted dollars, discounted at 

three percent, and discounted at seven percent. 

18For more information see CPSC’s Draft 

Guidance for Estimating Value per Statistical Life 

(88 FR 17826), https://www.federalregister.gov/ 

documents/2023/03/24/2023-06081/notice-ofavailability-proposed-draft-guidance-for-estimatingvalue-per-statistical-life. 

in-use, in-scope gas furnaces and boilers 

will grow from 64.13 million in 2025 to 

90.49 million in 2054. 

B. Preliminary Description of Potential 

Costs and Benefits of the Rule 

Staff conducted a cost assessment of 

the proposed rule. The proposed rule 

would impose the following costs: 

increased variable costs of producing 

furnaces and boilers with CO sensors 

and shutoff capabilities; one-time 

conversion costs of redesigning and 

modifying factory operations for 

installing CO sensors; increased 

maintenance costs of gas furnaces and 

boilers to consumers; and deadweight 

loss 16 in the market caused by the 

increasing price due to regulation and 

the subsequent decline in sales. Staff 

performed a 30-year prospective cost 

assessment (2025–2054) on all four cost 

categories and estimated the total 

annualized cost from the proposed rule 

to be $602.27 million, discounted at 

three percent.17 Staff estimated the perunit cost of a gas furnace or boiler from 

the proposed rule to be $158.11, 

discounted at three percent. 

Staff also conducted a benefits 

assessment of the proposed rule. The 

benefits assessment accounted for the 

prevention of deaths and injuries from 

compliant gas furnaces and boilers, 

which staff monetized using the Value 

of Statistical Life (VSL) for deaths, and 

the Injury Cost Model (ICM) for injuries. 

Over the 30-year study period, staff 

estimated the proposed rule would 

prevent 576 deaths (19.20 deaths per 

year) and 160,699 injuries (5,357 per 

year). The total annualized benefits from 

the proposed are $356.52 million, 

discounted at three percent. Staff 

estimated the per-unit benefits from the 

proposed rule to be $93.60, discounted 

at three percent. Staff calculates net 

benefits (benefits less costs) to be 

¥$245.74 million on annualized basis, 

discounted at three percent. The net 

benefits on per-unit basis are ¥$64.51, 

discounted at three percent. 

Alternatively, this can be described as 

the proposed rule being a net cost of 

$64.51 per gas furnace or boiler, which 

represents approximately three percent 

of the average price of a gas furnace or 

boiler, to prevent an estimated 576 

deaths and 160,699 injuries over 30 

years. 

Finally, staff conducted a sensitivity 

analysis that showed if, by 2035 

manufacturers were able to develop 

compliant gas furnaces and boilers with 

CO sensors that did not need 

replacement, and if the analysis took 

into account that a child’s death is 

considered twice as costly as an adult 

death,18 the benefit-cost ratio would 

increase to 0.78. 

C. Evaluation of Voluntary Standards 

Based on staff’s evaluation of the 

relevant ANSI standards discussed in 

section V of the preamble, the 

Commission preliminarily determines 

that current U.S. voluntary standards do 

not adequately address the hazard of CO 

exposure from gas furnaces and boilers. 

Further, the Z21/83 Technical 

Committee and the subordinate 

Technical Subcommittees have no clear 

plan to address these hazards in the 

relevant voluntary standards. None of 

the commenters on the ANPR submitted 

any recommendations for proposed 

requirements, nor did any commenters 

submit an existing voluntary standard or 

a portion of one that would adequately 

address the CO exposure risk that this 

proposed rule would address. No 

standard or portion of a standard was 

submitted to the Commission under 

section 9(a)(5) of the CPSA. 

D. Alternatives to the Proposed Rule 

The Commission considered four 

alternatives to the proposed rule: (1) 

continue to work and advocate for 

change through the voluntary standards 

process; (2) rely on the use of residential 

CO alarms; (3) continue to conduct 

education and information campaigns; 

and (4) rely on recalls. Each alternative 

is discussed in detail below. 

1. Continue To Work and Advocate for 

Change Through the Voluntary 

Standards Process 

Section V of this preamble highlights 

CPSC staff’s participation in the 

voluntary standard development 

process for ANSI Z21.47, Z21.13, and 

Z21.86. Despite staff encouraging 

industry to adopt a standard that 

adequately addresses the hazard, and 

providing industry with the necessary 

factual foundation, industry has not 

adopted such a standard in over 20 

years. For this reason, the Commission 

is not adopting this alternative. 

2. Rely on the Use of Residential CO 

Alarms 

CPSC has long promoted CO alarm 

adoption and states have increasingly 

required CO alarms in homes over the 

last two decades. Yet there has not been 

a significant decline in CO injuries and 

fatalities, demonstrating that CO alarm 

adoption alone is insufficient to address 

the hazard. We also note that residential 

CO alarms may fail to alert due to 

battery failure, poor maintenance, 

manufacturer defect, age, incorrect 

installation, or defects. Finally, a CO 

alarm would not shut down a gas 

furnace or boiler producing a dangerous 

amount of CO and thus would require 

the occupant to properly recognize what 

to do when the alarm is triggered. For 

these reasons, the Commission is not 

adopting this alternative. 

3. Continue To Conduct Education and 

Information Campaigns 

Despite education and information 

campaigns by CPSC and others 

regarding CO hazards, CO death and 

injuries for gas furnaces and boilers 

remain high. Education and information 

campaigns alone have not adequately 

addressed the CO hazard from gas 

furnaces and boilers in the absence of a 

performance standard. For these 

reasons, the Commission is not adopting 

this alternative. 

4. Rely on Recalls 

Although not all instances of 

excessive CO concentrations result from 

a defect in the gas furnace or boiler, the 

Commission could seek voluntary or 

mandatory recalls of gas furnaces and 

boilers that present a substantial 

product hazard. Recalls only apply to an 

individual manufacturer and product, 

and generally do not extend to similar 

products, and occur only after 

consumers have purchased and used 

such products with possible resulting 

deaths or injuries due to exposure to the 

hazard. Additionally, recalls can only 

address products that are already on the 

market but do not directly prevent 

unsafe products from entering the 

market. In the absence of a rule, 

hazardous gas furnaces and boilers will 

continue to see sales of several million 

units annually and the stock of 

hazardous products will continue to 

grow. Additionally, while detached gas 

furnaces and boilers could be easily 

recalled, installed gas furnace and boiler 

recalls can be disruptive and costly. For 

these reasons, the Commission does not 

choose this alternative. 


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19Weighted average between retail price increase 

from gas furnaces ($65.22) and boilers ($81.10) for 

the first year impact of the rule. 

20Conversion costs were calculated in 2013 

dollars and reported in 2020 dollars adjusted for 

2013–2020 inflation using the Consumer Price 

Index-Urban. 

X. Initial Regulatory Flexibility 

Analysis 

Whenever an agency publishes an 

NPR, Section 603 of the Regulatory 

Flexibility Act (RFA), 5 U.S.C. 601–612, 

requires the agency to prepare an initial 

regulatory flexibility analysis (IRFA), 

unless the head of the agency certifies 

that the rule will not have a significant 

economic impact on a substantial 

number of small entities. The IRFA, or 

a summary of it, must be published in 

the Federal Register with the proposed 

rule. Under Section 603(b) of the RFA, 

each IRFA must address: 

(1) a description of why action by the 

agency is being considered; 

(2) a succinct statement of the 

objectives of, and legal basis for, the 

proposed rule; 

(3) a description of and, where 

feasible, an estimate of the number of 

small entities to which the proposed 

rule will apply; 

(4) a description of the projected 

reporting, recordkeeping, and other 

compliance requirements of the 

proposed rule, including an estimate of 

the classes of small entities which will 

be subject to the requirement and the 

type of professional skills necessary for 

preparation of the report or record; and 

(5) an identification, to the extent 

practicable, of all relevant Federal rules 

which may duplicate, overlap, or 

conflict with the proposed rule. 

The IRFA must also describe any 

significant alternatives to the proposed 

rule that would accomplish the stated 

objectives and that minimize any 

significant economic impact on small 

entities. 

A. Reason for Agency Action 

The intent of this rulemaking is to 

reduce deaths and injuries resulting 

from carbon monoxide leaks from gas 

furnaces and boilers by establishing a 

mandatory performance standard 

requiring gas furnaces and boilers to 

shut off or modulate when CO levels 

reach specified amounts for a certain 

duration. 

B. Objectives of and Legal Basis for the 

Rule 

The Commission proposes this rule to 

reduce the risk of death and injury 

associated with CO leakage from 

residential gas furnaces and boilers. 

This standard is promulgated under the 

authority of the CPSA. To issue a 

mandatory standard under CPSA 

section 7, 15 U.S.C. 2056, the 

Commission must follow the procedural 

and substantive requirements in section 

9 of the CPSA, 15 U.S.C. 2058. See 15 

U.S.C. 2056(a). 

C. Small Entities to Which the Rule Will 

Apply 

The proposed rule would apply to all 

manufacturers and importers of gas 

furnaces and gas boilers. CPSC staff is 

aware of as many as 70 firms 

manufacturing gas furnaces and boilers 

for the U.S. market. When accounting 

for subsidiaries and multiple brands 

provided by the same company, staff 

identified 20 parent firms. 

Using SBA guidelines, staff identified 

two small manufacturers of gas 

furnaces, three small manufactures of 

residential gas boilers, and one importer 

of gas furnaces that may fall within the 

scope the rule. The Commission 

requests comment on additional 

manufacturers and importers of gas 

furnaces and boilers that may meet the 

SBA definition of a small business. 

D. Compliance, Reporting, and RecordKeeping Requirements of Proposed Rule 

In accordance with Section 14 of the 

CPSA, 15 U.S.C. 2063, manufacturers 

would have to issue a General 

Certificate of Conformity (GCC) for each 

of their gas furnace or boiler models, 

certifying that the model complies with 

the proposed performance requirement. 

Each GCC must also be based on a test 

of each product or a reasonable testing 

program and provided to all distributors 

or retailers of the product. The 

manufacturer would have to comply 

with 16 CFR part 1110 concerning the 

content of the GCC, retention of the 

associated records, and any other 

applicable requirements. 

E. Federal Rules That May Duplicate, 

Overlap, or Conflict With the Proposed 

Rule 

No Federal rules duplicate, overlap, 

or conflict with the proposed rule. 

F. Potential Impact on Small Entities 

1. Impact on Small Manufacturers 

The preliminary regulatory analysis in 

Section IX of this preamble discusses 

costs more fully. Based on that analysis, 

to achieve compliance with the 

proposed rule’s performance 

requirements, small domestic 

manufacturers would incur costs from 

the increased variable costs of 

producing furnaces and boilers with CO 

sensors and shutoff capabilities and 

testing and certifying such products, as 

well as the one-time conversion costs of 

redesigning and modifying factory 

operations for installing CO sensors. 

Installing CO sensors and shutoff 

capabilities in a gas furnace or boiler is 

a variable cost that is attached to each 

unit produced. Staff used a Guidehouse 

study (Guidehouse 2021) to find that the 

cost to manufacturers (without any 

markup included) at an annual 

production level of 119,572 gas furnace 

and boiler units yields an average 

incremental cost of $66.47 per unit.19

This is an annual total of $7.95 million 

($66.47 × 119,572) for each small firm. 

Regarding the one-time conversion 

costs, DOE’s findings from its 2015 

Rules on Gas Residential Furnaces and 

Boilers (80 FR 13120 and 80 FR 17222) 

found an industry cost of $413.28 

million (inflated to 2021 dollars).20 This 

would suggest a maximum conversion 

cost for small firms of $69.02 million 

(16.7 percent × $413.28 million) or 

$13.80 million per firm among the small 

five manufacturers. 

2. Impact on Small Importers 

Staff identified one small importer of 

products that would be within the scope 

of the standard. Importers may pass on 

testing responsibility and GCC creation 

to the foreign manufacturers and then 

issue the resulting certificate. Changes 

in production and certification costs 

incurred by suppliers from the standard 

could be passed on to the importers, 

which in turn are likely to be passed 

onto consumers given the relatively 

inelastic demand for heating appliances. 

For this reason, the Commission does 

not believe that the proposed rule will 

have a significant impact on small 

importers. 

The Commission seeks public 

comment on information on importers 

of gas furnaces and boilers; specifically, 

how many are imported, how many 

different models each importer sells, 

and what technologies those models are 

currently using (atmospheric venting, 

condensing, non-condensing, premix 

power burners, etc.). The Commission 

also seeks public comment on 

information regarding to what degree 

supplying firms tend to pass on 

increases in production and regulatory 

costs to importers, and to what extent 

the ability to pass on these costs is 

limited by the ease with which 

importers can switch suppliers or 

substitute to alternative products, such 

as electrical furnaces and boilers. 

G. Alternatives for Reducing the 

Adverse Impact on Small Businesses 

The Commission considered four 

alternatives to the proposed rule: (1) 

continue to work and advocate for 

change through the voluntary standards 


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process; (2) rely on the use of residential 

CO alarms; (3) rely on education and 

information campaigns; and (4) rely on 

recalls. The Commission is not adopting 

these alternatives for the reasons in 

Section IX of the preamble. 

The Commission welcomes public 

comments on this IRFA. Small 

businesses that believe they would be 

affected by the proposed rule are 

encouraged to submit comments. The 

comments should be specific and 

describe the potential impact, 

magnitude, and alternatives that could 

reduce the impact of the proposed rule 

on small businesses. 

XI. Incorporation by Reference 

The Commission proposes to 

incorporate by reference: ANSI Z21.47– 

21, Standard: Gas-fired central furnaces; 

ANSI Z21.13–22, Standard: Gas-fired 

low-pressure steam and hot water 

boilers; and ANSI Z21.86–16, Standard: 

Vented Gas-fired space heating 

appliances. The Office of the Federal 

Register (OFR) has regulations regarding 

incorporation by reference. 1 CFR part 

51. Under these regulations, agencies 

must discuss, in the preamble to a final 

rule, ways in which the material the 

agency incorporates by reference is 

reasonably available to interested 

parties, and how interested parties can 

obtain the material. In addition, the 

preamble to the final rule must 

summarize the material. 1 CFR 

51.5(b)(3). 

In accordance with the OFR 

regulations, section IV of this preamble 

summarizes the major provisions of 

ANSI Z21.47–21, Standard: Gas-fired 

central furnaces; ANSI Z21.13–22, 

Standard: Gas-fired low-pressure steam 

and hot water boilers; and ANSI 

Z21.86–16, Standard: Vented gas-fired 

space heating appliances that the 

Commission incorporates by reference 

into 16 CFR part 1408. The standard 

itself is reasonably available to 

interested parties. Until the final rule 

takes effect, read-only copies of ANSI 

Z21.47–21, Standard: Gas-fired central 

furnaces; ANSI Z21.13–22, Standard: 

Gas-fired low-pressure steam and hot 

water boilers, and ANSI Z21.86–16, 

Standard: Vented gas-fired space 

heating appliances are available for 

viewing, at no cost, at https://

community.csagroup.org/login.jspa?

referer=%252Fgroups%252Fansistandards-view-access. Once the rule 

takes effect, a read-only copy of the 

standards will be available for viewing, 

at no cost, at https://

community.csagroup.org/login.jspa?

referer=%252Fgroups%252Fansistandards-view-access. Interested 

parties can also schedule an 

appointment to inspect a copy of the 

standard at CPSC’s Office of the 

Secretary, U.S. Consumer Product 

Safety Commission, 4330 East West 

Highway, Bethesda, MD 20814, 

telephone: (301) 504–7479; email: cpscos@cpsc.gov. Interested parties can 

purchase a copy of the three ANSI 

standards from the Canadian Standards 

Association, 8501 East Pleasant Valley 

Road Independence, OH 44131–5516: 

1–800–463–6727; www.csagroup.org/ 

store/. 

XII. Environmental Considerations 

Generally, the Commission’s 

regulations are considered to have little 

or no potential for affecting the human 

environment, and environmental 

assessments and impact statements are 

not usually required. See 16 CFR 

1021.5(a). The proposed rule is not 

expected to have an adverse impact on 

the environment and is considered to 

fall within the ‘‘categorical exclusion’’ 

for the purposes of the National 

Environmental Policy Act. 16 CFR 

1021.5(c). 

XIII. Preemption 

Executive Order (E.O.) 12988, Civil 

Justice Reform (Feb. 5, 1996), directs 

agencies to specify the preemptive effect 

of a rule in the regulation. 61 FR 4729 

(Feb. 7, 1996). The proposed regulation 

for gas furnaces and boilers is being 

promulgated under authority of the 

CPSA. 15 U.S.C. 2051–2089. Section 26 

of the CPSA provides that: 

whenever a consumer product safety 

standard under this Act is in effect and 

applies to a risk of injury associated with a 

consumer product, no State or political 

subdivision of a State shall have any 

authority either to establish or to continue in 

effect any provision of a safety standard or 

regulation which prescribes any 

requirements as to the performance, 

composition, contents, design, finish, 

construction, packaging or labeling of such 

product which are designed to deal with the 

same risk of injury associated with such 

consumer product, unless such requirements 

are identical to the requirements of the 

Federal Standard. 

15 U.S.C. 2075(a). Thus, the proposed 

rule would preempt non-identical state 

or local requirements for gas furnaces 

and boilers designed to protect against 

the same risk of injury, i.e., risk of injury 

and death associated with CO 

production and leakage from residential 

gas furnaces and boilers. 

States or political subdivisions of a 

state may apply for an exemption from 

preemption regarding a consumer 

product safety standard, and the 

Commission may issue a rule granting 

the exemption if it finds that the state 

or local standard (1) provides a 

significantly higher degree of protection 

from the risk of injury or illness than the 

CPSA standard, and (2) does not unduly 

burden interstate commerce. 15 U.S.C. 

2075(c). 

XIV. Effective Date 

The Administrative Procedure Act 

(APA) generally requires that the 

effective date of a rule be at least 30 

days after publication of a final rule. 5 

U.S.C. 553(d). Section 9(g)(1) of the 

CPSA states that a consumer product 

safety rule shall specify the date such 

rule is to take effect, and that the 

effective date must be at least 30 days 

after promulgation but cannot exceed 

180 days from the date a rule is 

promulgated, unless the Commission 

finds, for good cause shown, that a later 

effective date is in the public interest 

and publishes its reasons for such 

finding. 

The Commission preliminarily 

proposes an effective date of 18 months 

after publication of the final rule in the 

Federal Register. The rule would apply 

to gas furnaces and boilers 

manufactured after the effective date. 

The effective date of the proposed rule 

is based on staff’s assessment that, to 

comply with the final rule, 

manufacturers would have to: 

• Identify and establish contracts 

with suppliers of CO sensing or 

combustion control devices; 

• redesign the impacted gas furnaces 

and boilers to integrate CO sensing or 

combustion control devices; 

• work with gas control and control 

board manufacturers on redesigning gas 

controls and control boards to properly 

incorporate power and output signals 

from CO sensing or combustion control 

devices; 

• conduct qualification testing and 

analysis of CO sensing or combustion 

control devices integrated into impacted 

appliances; 

• retool manufacturing lines to allow 

for CO sensing or combustion control 

devices to be assembled into impacted 

appliances; 

• incorporate the CO sensing or 

combustion control devices into existing 

quality control procedures; 

• retrain assembly line staff on the 

redesigned gas appliances and retooled 

manufacturing lines; 

• incorporate the CO sensing or 

combustion control devices into the 

user, maintenance, and installation 

instruction manuals of impacted 

appliances; 

• develop new guidance for 

distributors and retail outlets for the 

impacted appliances; and 


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• test and certify of the new models 

to voluntary standards required in many 

jurisdictions to meet building codes. 

A shorter effective date would likely 

result in manufacturers being unable to 

produce compliant products or produce 

enough products to meet their typical 

demand; resulting in a product shortage 

in the supply chain, consumers being 

denied their preferred product with a 

loss of utility and potentially an 

additional cost; and quality control 

issues. 

We note the proposed 18-month 

effective date is consistent with the 

applicable voluntary standards for gas 

furnaces, boilers, and wall and floor 

furnaces (i.e., ANSI Z21.13, ANSI 

Z21.47, and ANSI Z21.86, as well as all 

other ANSI Z21 standards), which 

typically allow for an effective date of 

18 months after new standards 

provisions are approved. While the 

proposed 18-month effective date is a 

departure from the 180-day default 

effective date required by section 9(g)(1) 

of the CPSA, the Commission 

preliminarily concludes that there is 

good cause here to set the effective date 

at 18 months for manufacturers to 

ensure compliance with the proposed 

performance requirements of the rule 

based on the reasons discussed above. A 

detailed discussion of the justification 

for the recommended 18 month effective 

date is available in the Staff NPR 

Briefing Package. The Commission seeks 

comments on the effective date with 

specific information to support any 

argument that an effective date longer 

than the 180-day period specified in 

CPSA section 9(g)(1) is or is not justified 

by good cause, including for the reasons 

preliminarily identified above. 

XV. Paperwork Reduction Act 

This proposed rule contains 

information collection requirements that 

are subject to public comment and 

review by the Office of Management and 

Budget (OMB) under the Paperwork 

Reduction Act of 1995 (PRA). 44 U.S.C. 

3501–3520. We describe the provisions 

in this section of the document with an 

estimate of the annual reporting burden. 

Our estimate includes the time for 

gathering certificate data and creating 

General Certificates of Conformity 

(GCC), the keeping and maintaining of 

records associated with the GCCs, and 

the disclosure of GCCs to distributers 

and retails. 

CPSC particularly invites comments 

on: (1) whether the collection of 

information is necessary for the proper 

performance of the CPSC’s functions, 

including whether the information will 

have practical utility; (2) the accuracy of 

the CPSC’s estimate of the burden of the 

proposed collection of information, 

including the validity of the 

methodology and assumptions used; (3) 

ways to enhance the quality, utility, and 

clarity of the information to be 

collected; (4) ways to reduce the burden 

of the collection of information on 

respondents, including the use of 

automated collection techniques, when 

appropriate, and other forms of 

information technology; and (5) 

estimated burden hours associated with 

label modification, including any 

alternative estimates. 

Title: Safety Standard for Gas 

Furnaces and Boilers. 

Description: The proposed rule would 

require each gas furnace and boiler to 

comply with performance requirements 

under which the appliance shuts off or 

modulates when CO levels reach 

specified amounts for a certain time 

duration. 

Description of Respondents: Persons 

who manufacture or import gas furnaces 

and boilers. Staff estimates the burden 

of this collection of information as 

follows in Table 2: 

TABLE 2—ESTIMATED ANNUAL REPORTING BURDEN

Burden type Number of 

respondents 

Frequency 

of responses 

Total annual 

responses 

Minutes 

per response 

Total burden 

hours Annual cost 

GCC Creation .......................................... 20 500 10,000 5 833 $63,525 

Recordkeeping ......................................... 20 500 10,000 1.25 208 7,005 

Third Party Disclosure ............................. 20 500 10,000 15 2,500 84,200 

Section 14(a)(1) of the CPSA, 15 

U.S.C. 2063(a)(1), would require 

manufacturers to certify that their 

products conform to the proposed rule 

and issue a GCC. There are 20 known 

corporate entities supplying gas 

furnaces and boilers to the U.S. market. 

On average, each entity may issue 500 

certificates for complying gas furnaces 

or boilers in the market. Each 

manufacturer or importer may issue 500 

certificates for a total of 10,000 

certificates (20 firms times 500 

certificates per firm = 10,000 

certificates). Staff treats each certificate 

issued as a new recordkeeping response 

so there is a total of 10,000 responses for 

GCC creation. The estimated time 

required to issue a GCC is estimated at 

about five minutes (although it often 

could be less). To comply with the 

CPSA, gas furnace and boiler 

manufacturers covered by the rule must 

subject their products to a reasonable 

testing program. Quality control and 

testing is usual and customary for gas 

furnace and boiler manufacturers, 

however creation (i.e., recording of test 

results) may not be. Staff estimates that 

each firm may spend five minutes per 

certificate issued recording the results of 

a reasonable testing program. This 

would include the time taken to read 

the test results, create the testing record, 

and issue a certificate. Therefore, the 

estimated burden associated with 

issuance of GCCs is 833 hours (10,000 

responses × 5 minutes per response = 

50,000 minutes or 833 hours). Staff 

estimates the hourly compensation for 

the time required to issue GCCs is 

$76.26 (U.S. Bureau of Labor Statistics, 

‘‘Employer Costs for Employee 

Compensation,’’ March 2023, Table 4, 

management, business, and financial 

occupations: https://www.bls.gov/ 

news.release/pdf/ecec.pdf). Therefore, 

the estimated annual cost to industry 

associated with issuance of a GCC is 

$63,525 ($76.26 per hour × 833 hours). 

We estimate for the purpose of this 

burden analysis that records supporting 

GCC creation, including testing records, 

would be maintained for a five-year 

period. Staff estimates another 10,000 

recordkeeping responses, each one of 

which requires 1.25 minutes per year in 

routine recordkeeping. This adds up to 

12,500 minutes or 208 hours. Staff 

estimates the hourly compensation for 

the time required to issue is $33.68 (U.S. 

Bureau of Labor Statistics, ‘‘Employer 

Costs for Employee Compensation,’’ 

March 2023, Table 4, office and 

administrative support occupations: 

https://www.bls.gov/news.release/pdf/ 

ecec.pdf). Therefore, the estimated 

annual cost to industry associated with 

recordkeeping associated with GCCs is 

$7,005 ($33.68 per hour × 208 hours). 

Section 14(g)(3) of the CPSA also 

requires that GCCs be disclosed to third 

party retailers and distributors. Staff 

estimates another 10,000 third party 

disclosure responses, each one of which 


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requires 15 minutes per year. This adds 

up to 150,000 minutes (10,000 

responses × 15 minutes per response) or 

2,500 hours. Staff uses an hourly 

compensation for the time required to 

disclose certificates to third parties of 

$33.68 (U.S. Bureau of Labor Statistics, 

‘‘Employer Costs for Employee 

Compensation,’’ March 2023, Table 4, 

office and administrative support 

occupations: https://www.bls.gov/ 

news.release/pdf/ecec.pdf). Therefore, 

the estimated annual cost to industry 

associated with third party disclosure of 

GCCs is $84,200 ($33.68 per hour × 

2,500 hours). There are no operating, 

maintenance, or capital costs associated 

with the collection. 

Based on this analysis, the proposed 

standard for gas furnaces and boilers 

would impose a total paperwork burden 

to industry of 4,374 hours (833 hours + 

833 + 208 hours + 2,500 hours), at an 

estimated cost of $154,730 annually 

($63,525 + $7,005 + $84,200). Existing 

gas furnace and boiler manufactures 

would incur these costs in the first year 

following the proposed rule’s effective 

date. In subsequent years, costs could be 

less, depending on the number of new 

GCCs issued for gas furnaces and 

boilers. As required under the PRA (44 

U.S.C. 3507(d)), CPSC has submitted the 

information collection requirements of 

this proposed rule to the OMB for 

review. Interested persons are requested 

to submit comments regarding 

information collection by December 26, 

2023, to the Office of Information and 

Regulatory Affairs, OMB as described 

under the ADDRESSES section of this 

notice. 

XVI. Certification 

Section 14(a)(1) of the CPSA requires 

that products subject to a consumer 

product safety rule under the CPSA, or 

to a similar rule, ban, standard or 

regulation under any other act enforced 

by the Commission, must be certified 

with a GCC as complying with all 

applicable CPSC-enforced requirements. 

15 U.S.C. 2063(a). A final rule would 

subject gas furnaces and boilers to this 

requirement. 

XVII. Promulgation of a Final Rule 

Section 9(d)(1) of the CPSA requires 

the Commission to promulgate a final 

consumer product safety rule within 60 

days of publishing a proposed rule. 

Otherwise, the Commission must 

withdraw the proposed rule if it 

determines that the rule is not 

reasonably necessary to eliminate or 

reduce an unreasonable risk of injury 

associated with the product or is not in 

the public interest. However, the 

Commission can extend the 60-day 

period, for good cause shown, if it 

publishes the reasons for doing so in the 

Federal Register. 15 U.S.C. 2058(d)(1). 

The Commission finds that there is 

good cause to extend the 60-day period 

for this rulemaking. Under both the 

APA and the CPSA, the Commission 

must provide an opportunity for 

interested parties to submit written 

comments on a proposed rule. 5 U.S.C. 

553; 15 U.S.C. 2058(d)(2). The 

Commission is providing 60 days for 

interested parties to submit written 

comments. A shorter comment period 

may limit the quality and utility of 

information CPSC receives, particularly 

for areas where it seeks data and other 

detailed information that may take time 

for commenters to compile. 

Additionally, the CPSA requires the 

Commission to provide interested 

parties with an opportunity to make oral 

presentations of data, views, or 

arguments. 15 U.S.C. 2058. This may 

require time for the Commission to 

arrange a public meeting for this 

purpose and provide notice to interested 

parties in advance of that meeting. After 

receiving written and oral comments, 

CPSC staff must have time to review and 

evaluate those comments. 

These factors make it impractical for 

the Commission to issue a final rule 

within 60 days of this proposed rule. 

Accordingly, the Commission finds that 

there is good cause to extend the 60-day 

period for promulgating the final rule 

after publication of the proposed rule. 

XVIII. Request for Comments 

We invite all interested persons to 

submit comments on all aspects of the 

proposed rule. The Commission 

particularly seeks comment on the 

following items: 

• the CO concentration and 

associated time thresholds in the 

proposed performance requirements; 

• the proposed fail safe provisions in 

the performance requirement; 

• the efficacy of the proposed fail safe 

provisions and whether there is a more 

appropriate approach to address fail 

safe; 

• should the proposed performance 

requirement include an audible alarm 

notification requirement that indicates 

when a gas furnace or boiler exceeds the 

proposed CO limits or when a CO 

sensor is no longer working properly; 

• effort required to obtain sensors and 

information on sensors including the 

lifespan; 

• effort required to redesign control 

systems; 

• effort required to test prototypes; 

• effort required to bring reengineered appliances to production; 

• costs associated with an effective 

date six months after publication of the 

rule; 

• costs associated with an effective 

date 30 days after publication of the 

rule; 

• costs associated with shipping and 

inventory of gas furnaces and boilers; 

• costs associated with manufacturing 

gas furnaces and boilers, along with a 

description of the process including the 

timing and whether any firms have 

seasonal production; 

• under the proposed stockpiling 

provision should zero-production 

months be averaged in to maintain a 

roughly constant level of supply for a 

seasonally produced product to avoid 

dramatic stockpiling if the manufacturer 

converted to constant production; 

• effort required to incorporate 

sensors and/or combustion control 

systems in production; 

• data or information on research and 

development and modifications to the 

production process the proposed rule 

would impose on manufacturers; 

• data or information on price 

elasticity for gas furnaces or boilers; 

• additional manufacturers and 

importers of gas furnaces and boilers 

that may meet the Small Business 

Administration (SBA) definition of a 

small business; 

• information on importers of gas 

furnaces and gas boilers, specifically: 

Æ how many are imported; 

Æ how many different models each 

importer sells; and 

Æ what technologies those models are 

currently using (atmospheric venting, 

condensing, non-condensing, premix 

power burners, etc.); and 

• information regarding the degree to 

which supplying firms are able to pass 

on increases in production and 

regulatory costs to importers. 

XIX. Notice of Opportunity for Oral 

Presentation 

Section 9 of the CPSA requires the 

Commission to provide interested 

parties ‘‘an opportunity for the oral 

presentation of data, views, or 

arguments.’’ 15 U.S.C. 2058(d)(2). The 

Commission must keep a transcript of 

such oral presentations. Id. Any person 

interested in making an oral 

presentation must contact the 

Commission, as described under the 

DATES and ADDRESSES section of this 

notice. 

List of Subjects in 16 CFR Part 1408 

Administrative practice and 

procedure, Consumer protection, 

Incorporation by reference, Gas furnaces 

and boilers. 


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■ For the reasons discussed in the 

preamble, the Commission proposes to 

amend Title 16 of the Code of Federal 

Regulations by adding a new part to 

read as follows: 

PART 1408—SAFETY STANDARD FOR 

RESIDENTAL GAS FURNACES AND 

BOILERS 

Sec. 

1408.1 Scope, purpose, and effective date. 

1408.2 Definitions. 

1408.3 Performance requirements for 

residential gas furnaces and boilers. 

1408.4 Incorporation by reference. 

1408.5 Prohibited stockpiling. 

Appendix A—Preliminary Findings Under 

the Consumer Product Safety Act 

Authority: 15 U.S.C. 2056, 15 U.S.C. 2058, 

and 5 U.S.C. 553. 

§ 1408.1 Scope, purpose, and effective 

date. 

This part establishes performance 

requirements for residential gas 

furnaces, boilers, and wall and floor 

furnaces (gas furnaces and boilers) that 

are consumer products used to heat 

dwellings, including but not limited to, 

single family homes, townhomes, 

condominiums, and multifamily 

dwellings, as well as multi-family 

buildings such as apartments and 

condominiums. The purpose of these 

requirements is to reduce the 

occurrence of carbon monoxide-related 

deaths, injuries, and exposures 

associated with gas furnaces and boilers. 

All residential gas furnaces and boilers 

manufactured after [DATE 18 MONTHS 

AFTER PUBLICATION OF THE FINAL 

RULE IN THE FEDERAL REGISTER] 

must meet the requirements of this part. 

§ 1408.2 Definitions. 

Gas Central Furnace means a gasburning appliance that heats air by the 

transfer of heat of combustion through 

a heat exchanger and supplies heated air 

through ducts to spaces remote from or 

adjacent to the appliance location. 

Gas Floor Furnace means a furnace 

suspended between the floor joists of 

the space being heated. A floor furnace 

provides direct heating of the room in 

which it is located and to adjacent 

rooms. 

Gas Steam and Hot Water Boiler 

means a gas burning appliance that 

heats steam at a pressure not exceeding 

15 psi (100 kPa), or hot water at a 

pressure not exceeding 160 psi (1100 

kPa) and at a temperature not exceeding 

250 °F (121 °C). The heated steam or 

water is pumped to spaces remote from 

or adjacent to the appliance location 

through piping to radiators, where the 

heat of combustion is transferred to heat 

the air around the radiator. 

Gas Wall Furnace means a gas 

appliance installed within a wall that 

provides heated air directly to the room 

in which it is installed and to adjacent 

rooms through grilles. 

§ 1408.3 Performance requirements for 

residential gas furnaces and boilers. 

(a) General. All residential vented gas 

furnaces, boilers, wall furnaces, and 

floor furnaces must have a means to 

either directly or indirectly monitor the 

concentration of carbon monoxide (CO) 

produced during the combustion 

process (i.e., ‘‘CO emissions’’), and shut 

down or modulate combustion to reduce 

average CO concentrations to below the 

CO levels for the durations of time 

specified in paragraph (b) of this 

section. If the average CO emissions 

reach or exceed the CO limits and time 

durations specified in paragraph (b), 

then the gas furnace or boiler must 

either shut down or modulate 

combustion to reduce average CO 

emissions to below 150 ppm. If average 

CO levels range between 200 and 299 

ppm for 50 minutes, then the gas 

furnace or boiler must either shut down 

or modulate combustion to reduce 

average CO emissions to below 150 

ppm. If average CO levels range between 

300 and 399 ppm for 40 minutes, then 

the gas furnace or boiler must either 

shut down or modulate combustion to 

reduce average CO emissions to below 

150 ppm. If average CO levels range 

between 400 and 499 ppm for 30 

minutes, then the gas furnace or boiler 

must either shut down or modulate 

combustion to reduce average CO 

emissions to below 150 ppm. If average 

CO levels range from 500 ppm or higher 

for 15 minutes, then the gas furnace or 

boiler must either shut down or 

modulate combustion to reduce average 

CO emissions to below 150 ppm. 

Indirect monitoring and control of CO 

emissions can be accomplished by 

monitoring and controlling other 

combustion parameter(s) that accurately 

correlate to the production of CO. 

Examples of parameters that can serve 

as a proxy for CO production include 

carbon dioxide (CO2), oxygen (O2), the 

Gas/Air Ratio, and the flame ionization 

current produced by the burner flame. 

(b) Performance requirements for gas 

furnaces and boilers. A gas furnace, 

boiler, wall furnace, or floor furnace 

must be equipped with a means to 

continuously monitor CO emission and 

must meet the requirements using one 

of the methods described in either 

paragraph (b)(1)(i) or paragraph (b)(2)(i) 

for the multipoint method or paragraph 

(b)(1)(ii) or (b)(2)(ii) for the single point 

method of this section when tested 

using the test method described in 

paragraph (d) of this section. 

(1) Direct means to monitor CO 

emissions. (i) Multipoint method. A gas 

furnace, boiler, wall furnace, or floor 

furnace equipped with a means to 

directly monitor CO emissions, must 

either cause shut down of the gas 

furnace or boiler or cause modulation of 

the gas furnace or boiler combustion, in 

response to the following conditions 

within the gas furnace or boiler: 

(A) average CO concentration is 500 

ppm or higher for 15 minutes; 

(B) average CO concentration between 

400 ppm and 499 ppm for 30 minutes; 

(C) average CO concentration between 

300 ppm and 399 ppm for 40 minutes; 

(D) average CO concentration between 

200 ppm and 299 ppm for 50 minutes; 

(E) average CO concentration between 

150 and 199 ppm for 60 minutes. 

(ii) Single point method. A 

manufacturer may use the single point 

method instead of the multipoint 

method described in paragraph (b)(1)(i) 

for a gas furnace, boiler, wall furnace, or 

floor furnace equipped with a means to 

directly monitor CO emissions; which 

must either cause shut down of the gas 

furnace or boiler or cause modulation of 

the gas furnace or boiler combustion, in 

response to the following conditions 

within the gas furnace or boiler: 

(A) Average CO concentration of 150 

ppm or higher for 15 minutes. 

Shutdown or modulation of the gas 

furnace or boiler must begin 

immediately after any of the conditions 

described in paragraphs (b)(1)(i)(A) 

through (E) are reached or the 

alternative condition described in 

paragraph (b)(1)(ii)(A) is reached. After 

modulation begins, the CO 

concentration within the gas furnace or 

boiler must be reduced to below 150 

ppm within 15 minutes. 

(B) [Reserved] 

(2) Indirect means to monitor CO 

emissions. (i) Multipoint method. A gas 

furnace, boiler, wall furnace, or floor 

furnace equipped with an indirect 

means to monitor CO emissions, must 

either cause shut down of the gas 

furnace or boiler or cause modulation of 

combustion of the gas furnace or boiler, 

each in response to the combustion 

conditions that correlate to the 

following conditions within the gas 

furnace or boiler: 

(A) average CO concentration is 500 

ppm or higher for 15 minutes; 

(B) average CO concentration between 

400 ppm and 499 ppm for 30 minutes; 

(C) average CO concentration between 

300 ppm and 399 ppm for 40 minutes; 

(D) average CO concentration between 

200 ppm and 299 ppm for 50 minutes; 


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Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 73291 

(E) average CO concentration between 

150 and 199 ppm for 60 minutes. 

(ii) Single Point method. A 

manufacturer may use the single point 

method instead of the multipoint 

method described in paragraph (b)(2)(i) 

for a gas furnace, boiler, wall furnace, or 

floor furnace equipped with a means to 

indirectly monitor CO emissions, which 

must either cause shut down of the gas 

furnace or boiler or cause modulation of 

combustion within the gas furnace or 

boiler, in response to the following 

condition within the gas furnace or 

boiler: 

(A) Average CO concentration of 150 

ppm or higher for 15 minutes. 

Shutdown or modulation of the gas 

furnace or boiler must begin 

immediately after any of the conditions 

described in paragraphs (b)(2)(i)(A) 

through (E) are reached or the 

alternative condition described in 

paragraph (b)(2)(ii)(A) is reached. After 

modulation begins, the CO 

concentration within the gas furnace or 

boiler must be reduced to below 150 

ppm within 15 minutes. 

(B) [Reserved] 

(3) Fail Safe. During the life of the gas 

furnace or boiler, if a CO sensor, 

combustion sensor, combustion control 

system, or other device designed to meet 

these requirements fails to operate 

properly or at all, then the gas furnace 

or boiler must shutdown and restart 

after 15 minutes and repeat this cycle 

until the failed component is replaced. 

Consumers and service technicians 

must be notified of device failure by 

either a flashing light or other 

appropriate code on the gas furnace or 

boiler control board that corresponds to 

the device failure. 

(c) Test Configuration. Gas furnace or 

boilers must be configured in the 

following manner for testing. Gas 

Furnaces, boilers, wall furnaces, and 

floor furnaces must each be set up with 

the burner and primary air adjusted in 

accordance with the provisions of the 

Combustion sections of the respective 

voluntary standards (section 5.8.1 of 

ANSI Z21.47–2021 for gas furnaces; 

section 5.5.1 of ANSI Z21.13–2022 for 

gas boilers; and sections 9.3.1, 11.2.1, 

and 13.3.1, of ANSI Z21.86–2016 for gas 

wall and floor furnaces). These tests 

must be conducted in an atmosphere 

having normal oxygen supply of 

approximately 20.94 percent. Burner 

and primary air adjustments must be 

made for furnaces, boilers, wall 

furnaces, and floor furnaces in 

accordance with the provisions of each 

respective standard (section 5.5.4 of 

ANSI Z21.47–2021 for gas furnaces; 

section 5.3.1 of ANSI Z21.13–2022 for 

gas boilers; and section 2.3.4 of ANSI 

Z21.86–16 for gas wall and floor 

furnaces). After adjustment, and with all 

parts of the furnace, boiler, wall furnace, 

or floor furnace at room temperature, 

the pilot(s), if provided, must be placed 

in operation and allowed to operate for 

a period of five minutes. The main 

burner(s) must then be placed in 

operation and the gas furnace or boiler 

operated for three minutes at normal 

inlet test pressure at which time a 

sample of the flue gases must be 

secured. Immediately upon securing the 

sample at normal inlet test pressure, the 

reduced inlet test pressure (section 5.5.1 

of ANSI Z21.47:2021; section 5.3.1 of 

ANSI Z21.13–2022; and section 2.3.1 of 

ANSI Z21.86–16) must be applied and, 

following a purge period of at least two 

minutes, another sample of the flue 

gases must be secured. For atmospheric 

burner units, samples must be secured 

at a point preceding the inlet to the 

unit’s draft hood or flue outlet where 

uniform samples can be obtained. The 

flue gas sample must be analyzed for 

carbon dioxide and carbon monoxide. 

The average concentration of carbon 

monoxide for the flue gas samples must 

not exceed 150 ppm in a sample of flue 

gases after 15 minutes. 

(d)(1) Test Procedure. To test a 

furnace, boiler, wall furnace, or floor 

furnace to the performance 

requirements specified in paragraph (b) 

of this section, induce the production of 

CO or related combustion parameters, 

one or a combination of the following 

methods must be used: 

(i) Progressively increase the gas 

control valve’s outlet pressure until the 

unit produces a CO concentration of 

approximately 150 ppm ±10 ppm CO. 

For natural gas units, use a propane 

conversion kit to achieve the desired CO 

concentration if this was not 

accomplished by increasing the gas 

valve’s outlet pressure. For propane 

units, use either option in paragraph 

(b)(2)(i)(B) or (C). If neither option 

results in a CO concentration of 

approximately 150 ppm, then use both 

options in paragraphs (b)(3)(i)(B) and 

(C). Once a CO concentration of at least 

150 ppm is achieved, that condition 

must be maintained for 15 minutes. 

(ii) Progressively block the exhaust 

vent or flue outlet until the unit 

produces approximately 150 ppm ±10 

ppm CO. Disable the unit’s blocked vent 

shutoff switch (BVSS) if necessary, in 

order to achieve the desired CO 

concentration. Once a CO concentration 

of approximately 150 ppm is achieved, 

that condition must be maintained for 

15 minutes. 

(iii) Reduce the fan speed of the 

inducer motor or premix power burner 

(for induced draft or premix power 

burner units only) by reducing the 

supply voltage to 85 percent of the gas 

furnace or boiler rating plate voltage 

until the unit produces a CO 

concentration of approximately 150 

ppm ±10 ppm CO. An additional 

combustion sample must be secured 

with the gas furnace or boiler operating 

at normal inlet test pressure and with 

the supply voltage reduced to 85 

percent of the gas furnace or boiler 

rating plate voltage. This sample must 

be secured 15 minutes after the furnace 

has operated at the reduced voltage. The 

input rating may vary from normal as a 

result of the voltage reduction. Once a 

CO concentration of approximately 150 

ppm is achieved, that condition must be 

maintained for 15 minutes. 

For gas furnaces and boilers that 

employ modulation (e.g., using a Gas/ 

Air Ratio Controller, an automatic steprate control, or automatic modulating 

controls, etc.) the unit must 

immediately begin modulation to 

reduce the CO concentration to below 

150 ppm. For gas furnaces and boilers 

that do not employ modulation, the unit 

must shut down. 

(2) Time for shutoff using multipoint 

method or modulation. The time for the 

gas to the main burner(s) to be shut off 

or begin modulation by the device used 

to directly or indirectly monitor CO 

emissions must be: 

(i) After 15 minutes at an average CO 

concentration of 500 ppm or more. 

(ii) After 30 minutes at an average CO 

concentration of 400–499 ppm. 

(iii) After 40 minutes at an average CO 

concentration of 300–399 ppm. 

(iv) After 50 minutes at an average CO 

concentration of 200–299 ppm. 

(v) After 60 minutes at an average CO 

concentration of 150–199 ppm. 

(3) Time for shutoff using single point 

method or modulation. A manufacturer, 

instead of using the multipoint method 

describe in paragraph (d)(2) may use the 

following single point conditions and 

time to shut off the gas furnace or boiler 

or begin modulation in response to the 

following condition within the gas 

furnace or boiler: 

(i) Average CO concentration of 150 

ppm or higher for 15 minutes. 

Shutdown or modulation of the 

appliance shall begin immediately after 

any of the conditions described in 

paragraph (d)(2) is reached. After 

modulation begins, the CO 

concentration within the appliance shall 

be reduced to below 150 ppm within 15 

minutes. 

(ii) [Reserved] 

§ 1408.4 Incorporation by reference. 

Certain material is incorporated by 

reference into this part with the 


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73292 Federal Register / Vol. 88, No. 205 / Wednesday, October 25, 2023 / Proposed Rules 

approval of the Director of the Federal 

Register in accordance with 5 U.S.C. 

552(a) and 1 CFR part 51. All approved 

incorporation by reference (IBR) 

material is available for inspection at 

the Consumer Product Safety 

Commission and at the National 

Archives and Records Administration 

(NARA). Contact the U.S. Consumer 

Product Safety Commission at: Office of 

the Secretary, U.S. Consumer Product 

Safety Commission, 4330 East-West 

Highway, Bethesda, MD 20814; 

telephone (301) 504–7479; email cpscos@cpsc.gov. For information on the 

availability of this material at NARA, 

visit www.archives.gov/federal-register/ 

CFR/IBR-locations.html or email 

fr.inspection@nara.gov. The following 

material may be obtained from the 

Canadian Standards Association, 8501 

East Pleasant Valley Road, 

Independence, OH 44131–5516: 1–800– 

463–6727; www.csagroup.org/store/: 

(a) ANSI Z21.13–2022, Standard: Gasfired low-pressure steam and hot water 

boilers, published August 2022. 

(b) ANSI Z21.47–2021, Standard: Gasfired central furnaces, published May 

2021. 

(c) ANSI Z21.86–2016, Standard: 

Vented gas-fired space heating 

appliances, published January 2017. 

§ 1408.5 Prohibited stockpiling. 

(a) Prohibited acts. Manufacturers and 

importers of gas furnaces, boilers, wall 

furnaces, and floor furnaces shall not 

manufacture or import products that do 

not comply with the requirements of 

this part between [DATE OF 

PUBLICATION OF FINAL RULE] and 

[EFFECTIVE DATE OF FINAL RULE] at 

a rate greater than 106 percent of the 

base period in the first 12 months after 

promulgation of the rule, and 112.50 

percent of the base period for the 

remaining six months until the effective 

date for the rule. 

(b) Base period. The base period for 

gas furnaces, boilers, wall furnaces, and 

floor furnaces is the calendar month 

with the median manufacturing or 

import volume within the last 13 

months immediately preceding the 

month of promulgation of the final rule. 

Appendix A to Part 1408—Preliminary 

Findings Under the Consumer Product 

Safety Act 

The Consumer Product Safety Act requires 

that the Commission, in order to issue a 

standard, make the following findings and 

include them in the rule. 15 U.S.C. 2058(f)(3). 

A. Degree and Nature of the Risk of Injury 

The Commission proposes this rule to 

reduce the risk of death and injury associated 

with CO production and leakage from 

residential gas furnaces, boilers, wall 

furnaces, and floor furnaces. Between 2017 to 

2019 (the most recent period for which data 

are complete), there were annually an 

estimated 21 CO deaths associated with 

residential gas furnaces and boilers. For the 

20-year period 2000 through 2019, these 

products were associated with a total of 539 

CO deaths. Between the years 2014 and 2018, 

236 nonfatal injuries were reported through 

the National Electronic Injury Surveillance 

System (NEISS) related to CO leakages from 

gas furnaces and boilers. Staff used NEISS 

incidents and the Injury Cost Model to 

extrapolate and generate national estimates 

for injuries from CO leakages from gas 

furnaces and boilers with 30,587 nonfatal 

injuries from CO leakages from 2014 to 2018. 

B. Number of Consumer Products Subject to 

the Rule 

An estimated 70 firms manufacturer 

residential gas furnaces and boilers. When 

accounting for subsidiaries and multiple 

brands provided by the same company, 20 

parent manufacturers have been identified. In 

2020, there was an estimated 60.94 million 

total number of residential gas furnaces and 

boilers in use. In 2021 residential gas furnace 

sales were estimated to be 3.58 million units, 

and 0.30 million units for gas boilers. 

C. Need of the Public for the Products and 

Probable Effect on Utility, Cost, and 

Availability of the Product 

(1) Residential gas furnaces and boilers are 

fueled by natural gas or propane (gas) and are 

used to heat all categories of residential 

dwellings, including single family homes, 

townhomes, condominiums, and multifamily 

dwellings, as well as small-to medium-sized 

commercial dwellings. Because the rule is a 

performance standard that allows for the sale 

of compliant gas furnaces and boilers, it is 

not expected to have an impact on the utility 

of the product. 

(2) The cost of compliance to address CO 

hazards include increased variable costs of 

producing furnaces and boilers with CO 

sensors and shutoff capabilities; one-time 

conversion costs of redesigning and 

modifying factory operations for installing 

CO sensors; increased maintenance costs of 

gas furnaces and boilers to consumers, and 

deadweight loss in the market caused by the 

increasing price due to regulation and the 

subsequent decline in sales. Staff performed 

a 30-year prospective cost assessment (2025– 

2054) on all four cost categories and 

estimated the total annualized cost from the 

proposed rule to be $602.27 million, 

discounted at three percent. Staff estimated 

the per-unit (of a gas furnace or boiler) costs 

from the proposed rule to be $158.11, 

discounted at three percent. 

Dead weight loss refers to the lost producer 

and consumer surplus from reduced 

quantities of gas furnaces and boilers sold 

and used due to the rule-induced increases 

in manufacturer cost and retail price. 

Producer surplus represents the difference 

between the amount a producer is willing to 

sell a good or service for and the price they 

actually receive. Consumer surplus 

represents the benefit that consumers receive 

from purchasing a good or service at a price 

that is lower than their willingness to pay. 

For those units no longer produced due to 

the rule, suppliers lose out on the producer 

surplus associated with those units, and 

consumers lose out on the consumer surplus 

associated with those units. 

In the first year, producer manufacturing 

costs are expected to increase by $22.08 per 

gas furnace causing a $70.44 per unit in 

higher retail costs to the consumer in the 

form of higher retail prices. Gas boiler 

manufacturing costs are expected to increase 

by $26.54 per unit causing an $87.59 in 

higher retail costs to the consumer. The 

resultant decrease in the number of gas 

furnaces and boilers sold and used is 

expected to generate a dead weight loss of 

about $1 million per year nationwide. 

(3) Staff does not expect that the 

availability of gas furnaces and boilers will 

be substantially impacted by the rule. Staff 

estimates baseline (status quo) sales of 3.96 

million units of gas furnaces and boilers in 

2025 which in the absence of the rule, would 

grow to 4.72 million by 2054. With the 

promulgation of the rule staff expects gas 

furnace and boiler sales of 3.92 million units 

in 2025 would grow to 4.69 million units by 

2054. 

D. Any Means To Achieve the Objective of 

the Rule, While Minimizing Adverse Effects 

on Competition and Manufacturing 

(1) The rule reduces CO hazards associated 

with residential gas furnaces and boilers 

while minimizing the effect on competition 

and manufacturing. Manufacturers can 

transfer some, or all, of the increased 

production cost to consumers through price 

increases. At the margins, some producers 

may exit the market because their increased 

marginal costs now exceed the increase in 

market price. Likewise, a very small fraction 

of consumers may be excluded from the 

market if the increased market price exceeds 

their personal price threshold for purchasing 

a gas furnace or boiler. However, the 

Commission did not find any information or 

assessment that would suggest significant 

changes to market competition or 

composition. 

(2) The Commission considered 

alternatives to the rule to minimize impacts 

on competition and manufacturing including: 

(1) continuing to work and advocate for 

change through the voluntary standards 

process; (2) relying on the use of residential 

CO alarms; (3) continuing to conduct 

education and information campaigns; and 

(4) relying on recalls. The Commission 

determines that none of these alternatives 

would adequately reduce the risk of deaths 

and injuries associated with the CO hazards 

presented by residential gas furnaces and 

boilers. 

E. The Rule (Including Its Effective Date) Is 

Reasonably Necessary To Eliminate or 

Reduce an Unreasonable Risk of Injury 

Between 2000 and December 2019, 

incident data show 539 fatal incidents related 

to CO hazards associated with gas furnaces 

and boilers. The incident data show that 

these incidents continue to occur and are 

likely to increase because the existing ANSI 

voluntary standards do not have 

requirements that would adequately reduce 


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1Though DEA has used the term ‘‘final order’’ 

with respect to temporary scheduling orders in the 

past, this notice of intent adheres to the statutory 

language of 21 U.S.C. 811(h), which refers to a 

‘‘temporary scheduling order.’’ No substantive 

change is intended. 

the CO hazard presented by gas furnaces and 

boilers and the market for gas furnaces and 

boilers is forecast to grow. The rule 

establishes performance requirements to 

address the risk of CO poisoning associated 

with residential gas furnaces and boilers. The 

effective date provides a reasonable amount 

of time for manufacturers to comply with the 

rule and produce products that prevent the 

CO hazard. Given the deaths and injuries 

associated with CO leakage from gas furnaces 

and boilers, the Commission finds that the 

rule and its effective date are necessary to 

address the unreasonable risk of injury 

associated with gas furnaces and boilers. 

F. Public Interest 

The rule addresses an unreasonable risk of 

death and injuries presented from CO 

hazards associated with gas furnaces and 

boilers. Adherence to the requirements of the 

rule would reduce deaths and injuries from 

CO poisoning associated with gas furnaces 

and boilers; thus, the rule is in the public 

interest. 

G. Voluntary Standards 

If a voluntary standard addressing the risk 

of injury has been adopted and implemented, 

then the Commission must find that the 

voluntary standard is not likely to eliminate 

or adequately reduce the risk of injury or 

substantial compliance with the voluntary 

standard is unlikely. The Commission 

determines that the relevant U.S. voluntary 

standards (ANSI Z21.13–2022, ANSI Z21.47– 

2021, and ANSI Z21.86–2016) do not contain 

performance requirements to protect against 

the known failure modes or conditions 

identified that have been associated with the 

production and leakage of CO into living 

spaces of U.S. residences resulting in 

numerous deaths and injuries, and thus do 

not adequately address the hazard of CO 

exposure from residential gas furnaces and 

boilers. 

H. Reasonable Relationship of Benefits to 

Costs 

The Commission determines the benefits 

expected from the rule bear a reasonable 

relationship to its costs. The rule 

significantly reduces the CO hazard 

associated with residential gas furnaces and 

boilers, and thereby reduces the societal costs 

of the resulting injuries and deaths. When 

costs are compared to benefits, the estimated 

costs of the rule are greater than the 

estimated benefits. Staff calculates net 

benefits (benefits less costs) to be ¥$245.74 

million on annualized basis, discounted at 

three percent. The net benefits on per-unit 

basis are ¥$64.51, discounted at three 

percent. Alternatively, this can be described 

as the proposed rule being a net cost of 

¥64.51 per gas furnace or boiler, which 

represents approximately three percent of the 

average price of a gas furnace or boiler. 

Overall, the proposed rule has a benefit-cost 

ratio of 0.59; in other words, for every $1 in 

cost of the proposed rule, there is a return of 

$0.59 in benefits from mitigated deaths and 

injuries. However, the rule is estimated to 

address 90–100 percent of deaths caused by 

the CO hazard associated with gas furnaces 

and boilers, resulting in potential total 

societal annualized benefits from the rule of 

$356.52 million, discounted at three percent. 

Staff conducted a sensitivity analysis that 

showed if by 2035 manufacturers were able 

to develop compliant gas furnaces and 

boilers with CO sensors that did not need 

replacement, and if the analysis took into 

account that a child’s death is considered 

twice as costly as an adult death, the benefitcost ratio would increase to 0.78. 

I. Least-Burdensome Requirement That 

Would Adequately Reduce the Risk of Injury 

The Commission considered four 

alternatives to the proposed rule: (1) continue 

to work and advocate for change through the 

voluntary standards process; (2) rely on the 

use of residential CO alarms; (3) continue to 

conduct education and information 

campaigns; and (4) rely on recalls. Although 

these alternatives may be less burdensome 

alternatives to the rule, the Commission 

determines that none of the alternatives 

would adequately reduce the risk of deaths 

and injuries associated with gas furnaces and 

boilers that is addressed by the rule. 

Elina Lingappa, 

Paralegal Specialist, Consumer Product 

Safety Commission. 

[FR Doc. 2023–23302 Filed 10–24–23; 8:45 am] 

BILLING CODE 6355–01–P 

DEPARTMENT OF JUSTICE 

Drug Enforcement Administration 

21 CFR Part 1308 

[Docket No. DEA–1143] 

Schedules of Controlled Substances: 

Temporary Placement of N-Desethyl 

Isotonitazene and N-Piperidinyl 

Etonitazene in Schedule I 

AGENCY: Drug Enforcement 

Administration, Department of Justice. 

ACTION: Proposed amendment; notice of 

intent. 

SUMMARY: The Administrator of the Drug 

Enforcement Administration is issuing 

this notice of intent to publish a 

temporary order to schedule two 

synthetic benzimidazole-opioid 

substances, including their isomers, 

esters, ethers, salts, and salts of isomers, 

esters, and ethers whenever the 

existence of such isomers, esters, ethers, 

and salts is possible, in schedule I of the 

Controlled Substances Act. When it is 

issued, the temporary scheduling order 

will impose the regulatory controls and 

administrative, civil, and criminal 

sanctions applicable to schedule I 

controlled substances on persons who 

handle (manufacture, distribute, reverse 

distribute, import, export, engage in 

research, conduct instructional 

activities or chemical analysis, or 

possess) or propose to handle these two 

specified substances. 

DATES: October 25, 2023. 

FOR FURTHER INFORMATION CONTACT: 

Terrence L. Boos, Drug and Chemical 

Evaluation Section, Diversion Control 

Division, Drug Enforcement 

Administration; Mailing Address: 8701 

Morrissette Drive, Springfield, Virginia 

22152; Telephone: (571) 362–3249. 

SUPPLEMENTARY INFORMATION: The notice 

of intent contained in this document is 

issued pursuant to the temporary 

scheduling provisions of 21 U.S.C. 

811(h). The Drug Enforcement 

Administration (DEA) intends to issue a 

temporary scheduling order 1 (in the 

form of a temporary amendment) to add 

the following two substances, including 

their isomers, esters, ethers, salts, and 

salts of isomers, esters, and ethers 

whenever the existence of such isomers, 

esters, ethers, and salts is possible, to 

schedule I under the Controlled 

Substances Act (CSA): 

• N-ethyl-2-(2-(4-isopropoxybenzyl)-5- 

nitro-1H-benzimidazol-1-yl)ethan-1- 

amine (commonly known as N-desethyl 

isotonitazene), and 

• 2-(4-ethoxybenzyl)-5-nitro-1-(2- 

(piperidin-1-yl)ethyl)-1H-benzimidazole 

(commonly known as either Npiperidinyl etonitazene or 

etonitazepipne). 

The temporary scheduling order will 

be published in the Federal Register on 

or after November 24, 2023. 

Legal Authority 

The CSA provides the Attorney 

General (as delegated to the 

Administrator of DEA (Administrator) 

pursuant to 28 CFR 0.100) with the 

authority to temporarily place a 

substance in schedule I of the CSA for 

two years without regard to the 

requirements of 21 U.S.C. 811(b), if he 

finds that such action is necessary to 

avoid an imminent hazard to the public 

safety. 21 U.S.C. 811(h)(1). In addition, 

if proceedings to control a substance are 

initiated under 21 U.S.C. 811(a)(1) while 

the substance is temporarily controlled 

under section 811(h), the Attorney 

General may extend the temporary 

scheduling for up to one year. 21 U.S.C. 

811(h)(2). 

Where the necessary findings are 

made, a substance may be temporarily 

scheduled if it is not listed in any other 

schedule under 21 U.S.C. 812, or if there 

is no exemption or approval in effect for 

the substance under section 505 of the 

Federal Food, Drug, and Cosmetic Act, 


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