U.S. Consumer Product Safety Commission

These comments are those of the CPSC staff, have not been reviewed or approved by, and may not 

necessarily reflect the views of, the Commission.

Staff Review of 

Portable Generator Safety

Briefing to the Commission

October 26, 2006
g

CO Poisoning Deaths

Charcoal grills, charcoal, 

5%

Camp stoves, lanterns, 

2%

Other/multiple 

appliances, 8%

Gas ranges/ovens, 2%

Engine-driven tools other 

than generators, 3%

Generators, 24%

Fuel-burning heating 

systems, 55%

Gas water heaters, 0.5%

Charcoal grills/charcoal, 5%

Other/multiple appliances, 8%

Gas ranges/ovens, 2%

Camp stoves, lanterns, 2%

Engine-driven tools other

than generators, 3%

Generators, 24%

Fuel-burning heating systems, 

Gas water heaters, 0.5%

Estimated CO Deaths by Category of Consumer Products, 2002
Product Information

• Fuel: Gasoline, diesel, propane, natural gas

• Electricity out: Cord-connected to appliances via receptacle

(120v, 240v) or to house wiring via transfer switch

• Primarily contractor market before 1999

• Consumer market growing rapidly since pre-Y2K

• Sold through home centers, hardware stores, discount 

retailers
Hazards from Portable Generators

• CO poisoning

• Shock and electrocution

• Fire

• Thermal contact burns
* For the years 1990 through 2001, these were the number reported to CPSC as of 6/27/2005

For the years 2002 through 2005, these were the number reported to CPSC as of 6/1/2006.

** The ICD-10 System was implemented in 1999.

p

0

10

20

30

40

50

60

70

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Year

Deaths

Fire-related (rpt'ed as of 12/7/05) Electrocution (rpt'ed as of 11/4/05) CO *

Deaths

1990

1991

1992

1993

1994

19951996

1997

1998

1999 **

20002001

20022003

2004

2005

Year
Estimates of CO Injuries

• Reports of fatal generator CO incidents often includ

survivors with severe CO injuries

• CPSC staff does not make national estimates of CO 

injuries

– NEISS records lack enough detail to confirm injury and associated 

consumer product

– Mild CO poisoning cases may be confused with common illnesses

• Survivors of serious CO exposures, from any source of CO, 

could be affected with severe disabilities

– Permanently with blindness, Parkinsonism, paralysis

– Temporarily with emotional instability, memory loss, dementia, 

psychosis, incontinence, peripheral neuropathy, blindness, 

Parkinsonism, paralysis
Summary of Investigated Fatal CO Incidents

Out of 137 fatal incidents involving 189 deaths: 

• 60 deaths: generator used during weather-induced power 

outage or problem with power distribution.

• 146 deaths: occurred at home; majority with generator in 

the basement/crawlspace, garage/enclosed carport, or livin

space of the home. 

• 24 deaths: appears consumer attempted to vent the indoor 

space where generator was operated.

• 5 deaths: generator was outside the home but near an ope

window, door, or vent.

* From incidents that occurred through 2004 that were reported to CPSC by 

6/27/05, a total of 274 deaths. National totals may not be derived from this da

as it is not a statistical sample.
Summary of Investigated Fatal CO Incidents

• 5.0 kW – 5.9 kW generator most commonly 

involved, when identified in IDI

• Two most common reasons for using the 

generator indoors: 

– Fear of generator theft

– Concern about noise to neighbors

• Almost all generators were referred to as gas or 

gasoline generators

* From incidents that occurred through 2004 that were reported to CPSC by 

6/27/05, a total of 274 deaths. National totals may not be derived from this 

data as it is not a statistical sample.
Consumer Portable Generator 

Ownership and Sales

Sources: * Synovate, Inc.

** Multi-Client Research Group, Synovate, Inc.

• 10.6 million units estimated in households in 2005, 

up from 9.2 million units in 2002*

• >1 million/year bought in 2003-2005**

• Approximately 40% bought in 2003-2005 were 

rated 5.0 kW to <6.5kW

• 60% of sales to consumers cost $300 - $800 per 

unit

• 98.7% of portable generators sold in 2003-2005 

were gasoline-fueled
Generator CO deaths

• 51 CO deaths/year, 2002-2005 average

• Average annual societal cost is $255M; ~$25 annua

societal cost per generator

• Based on 7-yr product life, estimated present value 

of expected societal cost/generator is $157

• Expected benefits for reduction in the hazard 

resulting from intervention

– 50% effectiveness: $79/generator

– 75% effectiveness: $118/generator

Estimate does not include societal costs related to 

deaths from electrocution and fire or any injuries
Possible Strategies to Address 

CO Poisoning Hazard

• Reduce consumer exposure to CO through technica

means

– Engines with substantially reduced CO emissions

– Automatic shutoff devices

• Enable and encourage proper generator placement

– Weatherization requirements

• For safe outdoor use in wet conditions

• For engine operation in icing conditions

– Theft deterrence

– Noise reduction

– Improved CO warning label and manufacturers’ guidance
Possible Strategies to Address 

CO Poisoning Hazard (cont)

• Private sector consortium

• Information and education
Technical Approaches to Reduce 

Consumer Exposure to CO

Goal: Protect consumers against CO 

poisoning that can result in death or in 

serious and/or lasting adverse health effects 

if they inadvertently operate generator in 

improper location

NOT TO MAKE GENERATORS SAFE FOR 

INDOOR USE!
CO Hazard Characterization

• Testing to determine CO generation rate of 

5.5 kW generator

• Modeling of most common incident scenario 

with generator operated in basement

– Predicted all occupants dead before fuel tank 

exhausted

• 40 minutes for person in basement

• Less than 5 hours for person in 2nd floor bedroom

• 10 hp generator engine produces CO at rate 

450-1000 times that of modern idling cars*

* Reference for idling automotive emissions: Frey, H., et al., On-Road Measurement of 

Vehicle Tailpipe Emissions Using a Portable Instrument, Journal of the Air & Waste 

Management Association, Vol. 53, August 2003.
Engines with Reduced CO Emissions

• Most reliable way to limit consumer exposure is to 

limit production of hazardous CO levels at the 

source

• Automotive engines

– Catalytic converters reduced CO emission by 96%

– Still unsafe to run in garages, but unintentional CO 

deaths declined >80%

• Marine generator engines

– 2 major manufacturers voluntarily reduced CO 

emissions >99% using catalytic converters and 

electronic fuel injection

– Reduce CO poisonings on and around houseboats
Are Substantial CO Emission Reductions 

Possible for Generator Engines?

• Respondents to RFI assert 90-95% reduction in CO 

emissions is readily achievable

– Catalytic converters alone or in conjunction with 

electronic fuel injection

• CPSC staff awarded contract to develop a low-CO 

generator prototype and demonstrate technical 

feasibility
Potential Impact of CO Emission Reduction

• Staff predicts that 90-95% reduction will result in improved 

survivability for most common incident scenario with generat

improperly operated in basement

– Can likely result in significant delay and reduced severity of CO 

exposure for all occupants, except those persons in the basement

– Allows them more time to become aware of symptoms and escape

– Depending on where they are in the house, they could survive withou

serious adverse effects even if they didn’t leave the house

• Established interagency agreement with NIST to estimate 

minimum CO emissions reductions to improve survivability 

when generator improperly operated in garage

– Identify engine modifications necessary to achieve this level of

reduction
Are Substantial CO Emission Reductions 

Practical for Generator Engines?

• Catalysts are in use on motorcycles in U.S., 

motor scooters in Asia

• Catalysts will be introduced onto engines used 

on generators to meet proposed CARB and yetto-be proposed EPA regulations

• Address technical and human factors issues

– Potential for catalyst heat increasing fire and burn 

hazards

– False sense of security leading to improper 

placement
Interlocking or Auto Shutoff Devices

• Sensors shutoff generator if CO buildup is detected

• CPSC staff demonstrated proof-of-concept for two 

approaches

– Detect CO in vicinity of operating generator

• CO sensor mounted on generator 

– Detect CO where occupants are located

• CO sensor in home with wireless connection to generator

• Address technical and human factors issues

– Sensor reliability and durability

– Locating in-home sensors in proper locations

– False sense of security
• Generators are not constructed for safe 

use in wet conditions

• Wet conditions often exist when there is a 

power outage

• Current CO warning labels do not 

unequivocally advise against indoor use

gp

Generator Placement: 

Weatherization Requirements
Examples of CO Warnings Found 

on Generators

Provide proper ventilation! Do not operate in a 

confined area due to carbon monoxide poisoning!
Examples of CO Warnings Found on 

Generators, cont’d
Weatherization Features

• Raintight or rainproof enclosure

• In-use weatherproof receptacle covers

• Ground fault protection for all receptacles

• These features may not be practical for 

some generator models or eliminate 

electrocution risk under severe conditions 

(e.g., flood)
Weatherization Requirements

Icing conditions that can bring down power lines 

can also cause engine to stall
Encourage Proper Generator Placemen

• Deter generator theft

– Mechanical devices to anchor, lock generator

• Reduce engine noise
Improve On-Product CO Warning Labe
Improve Manufacturers

Guidance

Current guidance may mislead consumers:
Private Sector Consortium

• A formal collaboration among 

manufacturers to develop effective 

technologies to address the hazard

– Needs Dept. of Justice approval

– Pooling resources to achieve common goal

– Can accelerate product development: or

– Can also impede progress if no consensus 

on approach 

• Consortium developed Flammable Vapor 

Ignition Resistant water heaters 
Information and Education

• CPSC’s Office of Public Affairs

– Press releases, VNRs, posters, publications

– Targeted distribution to regional outlets in anticipation o

major storms or in conjunction with widespread outages

• Expansion of I&E efforts to include all stakeholders

– Establish consistency in messages concerning the 

hazard and proper operation of generator

– Initiative with retailers to increase public awareness of 

the CO hazard associated with generators

– National education program delivered at community 

level
Cost Estimates of Strategies

• Engines with substantially reduced CO 

emissions: $40-$200 per RFI respondents

– In anticipation of CARB/EPA compliant 

engines with catalysts, staff expects lower 

cost

• Remote CO detection auto shutoff device: 

$100

• Theft deterrent features/accessories: $20

• National education program: > $3M per 

year
Standards & Regulations

• Draft voluntary standard UL 2201

• UL Outline of Investigation, Subject 2201

• ISO 8528-8:1995(E)

• CSA C22.2 No. 100-04

• OSHA regulations
Participation in Development of UL 220

• CPSC staff is non-voting member of STP that is 

drafting the first proposed edition of UL 2201, 

Portable Engine-Generator Assemblies.

• Staff has recommended requirements be 

developed to address:

– Consumer exposure to unsafe CO emissions

– Safe outdoor use in wet conditions

– Satisfactory engine operation in icing conditions

– Cautionary markings on product and packaging and in 

instruction manual

• Draft standard addresses CO hazard only through 

cautionary markings.

• STP consensus not yet achieved on draft 

standard.
UL Outline of Investigation, Subject 2201

UL issued an Outline of Investigation, Subject 2201 

on April 7, 2006

•Establishes certification requirements for 

generators to receive the UL mark

•Includes requirements for 

– features that will permit safe use in wet conditions

– warnings about CO poisoning on product and 

packaging and in instruction manual

•UL sought and received staff’s comments and 

recommendations

•Not currently a consensus document
ISO, CSA, OSHA Requirements

• ISO 8528-8:1995(E) Reciprocating IC Engine Driven AC 

Generating Sets – Part 8: Requirements and Tests for Low-Power 

Generating Sets

– CO hazard addressed through labels and markings

– Requires start-up and operation at temps 5oF to 104oF

• CSA C22.2 No. 100-04 Motors and Generators

– No requirements to address CO hazard

• OSHA Regulations 

– Define proper installation and use of portable generators at a 

temporary construction site or permanent workplace in which portab

generator is supplying power

– Address grounding and ground-fault protection

These documents do not adequately address the 

CO poisoning hazard for portable generators.
Conclusions and Recommendation

Effective intervention is urgently needed to 

address increasing CO deaths.

• Deaths occur predictably with severe weather.

• They also occur throughout the year, independent of weathe

• Consumer ownership is increasing.

• There is inadequate progress in developing effective volunta

standards that address the CO poisoning hazard.

• Most reliable way to address consumer exposure to CO is to 

reduce it at its source. This appears to be achievable. Cost 

and practicality will be assessed.

• Enabling and encouraging consumers to operate their 

generators in safe locations will help.

Staff recommends publishing an ANPR to 

initiate rulemaking in addition to pursuing 

non-regulatory options.