In 2006, the Commission issued an advance notice of proposed rulemaking (ANPRM) under the Consumer Product Safety Act (CPSA) concerning portable generators. The ANPRM discussed regulatory options that could reduce deaths and injuries related to portable generators, particularly those involving carbon monoxide (CO) poisoning. In fiscal year 2006, staff awarded a contract to develop a prototype generator engine with reduced CO in the exhaust. Also, in fiscal year 2006, staff entered into an interagency agreement (IAG) with the National Institute of Standards and Technology (NIST) to conduct tests with a generator, in both off-the-shelf and prototype configurations, operating in the garage attached to NIST's test house.  In fiscal year 2009, staff entered into a second IAG with NIST with the goal of developing CO emission performance requirements for a possible proposed regulation that would be based on health effects criteria. After additional staff and contractor work, the Commission issued a notice of proposed rulemaking (NPRM) in 2016, proposing a performance standard that would limit the CO emission rates from operating portable generators. In 2018, two voluntary standards adopted different CO-mitigation requirements intended to address the CO poisoning hazard associated with portable generators. Staff developed a simulation and analysis plan to evaluate the effectiveness of those voluntary standards' requirements. In 2019, the Commission sought public comments on staff's plan. In August 2020, staff submitted to the Commission a draft notice of availability of the modified plan, based on staff’s review and consideration of the comments, for evaluating the voluntary standards; the Commission published the notice of availability in August 2020. In February 2022, staff delivered a briefing package to the Commission with the results of the effectiveness analysis and information on the availability of compliant generators in the marketplace. Staff concluded that the CO hazard-mitigation requirements of one standard are more effective than the other, but conformance to either standard is low. Staff intends to deliver a supplemental NPRM rule and a Final Rule on portable generators to the Commission in fiscal year 2023.