The Joint Committee on Consumer Protection and Professional Licensure took testimony on House Bill 452, the agricultural equipment right‑to‑repair bill, during an October hearing in Boston.

Supporters said the bill would restore owners’ ability to maintain expensive equipment quickly. Opponents, including engine and truck manufacturers, contended broader access to control software and diagnostic tools would make it easier to tamper with emissions systems and risk public health.

The bill matters because modern tractors and other agricultural machines increasingly rely on integrated computers and software to control engine performance and emissions. Alan Schafer of the Engine Technology Forum told the committee those systems ‘‘work together to control combustion and treat emissions in real time’’ and warned the bill ‘‘would increase the risk of tampering with emissions control systems, a practice that’s typically in violation of the Federal Clean Air Act and would have significant negative impacts on air quality in Massachusetts.’’ Schafer cited a 2020 EPA estimate he said linked tampering with diesel engines to roughly 570,000 tons of excess NOx and 5,000 tons of particulate matter over a decade.

Manufacturers’ trade groups said existing voluntary agreements are already expanding access for owners. Patricia Hans of the Truck and Engine Manufacturers Association said major manufacturers and owners agreed to memoranda of understanding in 2023 establishing how information and parts are made available, and that complaints filed under those agreements have been few and resolved.

Farm groups, independent repair advocates and some lawmakers countered that voluntary memoranda are not legally binding and do not guarantee timely, affordable access to parts or diagnostic tools. Dan Bosley of the Massachusetts Farm Bureau Federation said the bureau, representing roughly 2,700 farm members, asked that the committee record opposition to H.452 in its current form. Willie Katie, who testified remotely as a farmer and stated he has worked on the issue for nine years, told the committee that ‘‘manufacturers use [proprietary software] so they can create a monopoly preventing necessary workers or businesses from being able to fix the equipment.’’ Representative Lawrence Metoon told the committee farm constituents complain of breakdowns that leave equipment idle for months while waiting for authorized service or factory codes.

Testimony touched on safety and liability as well as air quality. Manufacturers said software‑level repairs require specialized training and that improper changes can degrade emissions controls or create unsafe machine behavior. Farmer and repair advocates said owners routinely make repairs to keep harvests on schedule and that limiting access increases costs and downtime for family operations. ‘‘This is about helping Massachusetts farmers, the families that own farms, to be able to maintain their agricultural equipment in an affordable way,’’ Representative Metoon said.

Committee members asked for more detail about the scope of the problem and the effectiveness of the existing MOUs. Several lawmakers pressed witnesses on whether federal enforcement under the Clean Air Act, rather than state law, should be relied on to address tampering. Proponents replied that state law is needed to shore up owners’ rights and guarantee access locally.

The committee did not take a vote on H.452 during the hearing and heard both detailed technical and local‑impact testimony. Lawmakers asked staff to collect written submissions and additional technical information cited by witnesses, including the 2020 EPA report referenced by engine manufacturers and specifics about the 2023 memoranda of understanding between equipment makers and owner groups.

The hearing closed with multiple members asking for follow‑up materials and written comments. No formal committee action was taken during the session.