NOM-161-SEMARNAT-2011 sets out the criteria for classifying a waste stream as special management waste and determines which of those streams must have a management plan, along with the list of covered wastes and what a plan must contain. A special management waste that exceeds the threshold set in the standard's normative annex, or that comes from a large generator (10 tonnes or more a year, under Mexico's General Law for the Prevention and Integral Management of Waste), needs a management plan registered with the competent authority before operations start.
What counts as special management waste
The General Law for the Prevention and Integral Management of Waste (LGPGIR), in Article 5, section XXX, defines special management waste as waste generated in production processes that doesn't meet the characteristics to be classified as hazardous or as municipal solid waste. It's the in-between category: not hazardous enough to fall under direct federal jurisdiction, and not similar enough to household trash for the municipality to simply collect it.
Article 19 of the same law lists examples of this category: waste from health services, agricultural waste, construction waste, technological waste, used tyres and several others. NOM-161 is the standard that turns that general list into an operational annex, with concrete criteria and thresholds by waste type.
NOM-161's classification criteria
Under section 6 of the standard, for a waste to be classified as special management waste it must meet criterion 6.1 or 6.2, and always, in addition, criterion 6.3:
- 6.1: the waste is generated in extraction, transformation or processing activities and has neither household characteristics nor hazardous properties.
- 6.2: the waste is, by nature, municipal solid waste, but it's generated by a large generator (10 tonnes or more a year) and requires specific management outside the ordinary municipal service.
- 6.3: the waste is included in the state's basic waste diagnosis, or backed by a technical-economic study justifying its inclusion.
This last requirement is the one most often overlooked: it isn't enough for a waste to appear to fit the general definition, it must be formally incorporated into the relevant state's diagnosis or supported by a company's own study.
The list of wastes subject to a management plan
NOM-161's normative annex lists eight categories of special management waste subject to a management plan, several with a quantitative threshold:
| Category | Threshold or scope |
|---|---|
| Health services waste | Paper, clinical clothing, plastics, wood and glass generated at health facilities |
| Agroplastics | Plastics used in agricultural activities |
| Agricultural, poultry, livestock and fishing organic waste | No specific quantitative threshold in the annex |
| Federal and public transport waste | More than 10 tonnes a year |
| Wastewater treatment sludge | More than 100 tonnes a year |
| Department store waste | More than 10 tonnes a year |
| Construction waste | More than 80 cubic metres |
| End-of-life products | Electronics, vehicles, used oils, among others |
Note that the thresholds aren't uniform: 10 tonnes a year for federal transport and department stores, 100 tonnes a year for sludge, and 80 cubic metres for construction waste. Mixing up these thresholds between categories is one of the most common mistakes when assessing whether an operation needs a management plan.
The large-generator threshold
The LGPGIR, in Article 5, section XII, defines a large generator as any individual or legal entity generating a quantity equal to or greater than 10 tonnes of total gross weight of waste per year. This threshold is what triggers NOM-161's criterion 6.2 when the waste would, by nature, be municipal solid waste: crossing it takes the company out of the ordinary municipal collection circuit and requires specific management, with its own plan.
Who registers the plan: SEMARNAT or the state authority
Article 33 of the LGPGIR splits jurisdiction by waste type: SEMARNAT has authority over hazardous, mining and metallurgical waste; state authorities over special management waste; and municipal authorities over municipal solid waste. NOM-161, in section 10.3, specifies that the management plan is filed with the state (entidad federativa) corresponding to where it will be implemented. When the plan's modality is national or regional, that is, when it spans more than one state, it must also be filed with SEMARNAT.
States may keep public registries of the plans, provided they have the plan's promoter's prior authorisation to do so.
What a management plan must contain
Section 9 of the standard distinguishes between general elements, mandatory in every case, and additional elements depending on the plan's modality.
The general elements (9.1) are:
- Applicant information and that of their legal representative.
- A diagnosis of the waste, including the quantity generated.
- Proposed integral management methods.
- Recovery or recycling targets.
- The waste's final destination.
- Operating, control and monitoring mechanisms.
- Participants in the plan, where applicable.
- Communication mechanisms, where applicable.
Additional elements (9.2) come on top depending on modality: for private plans, infrastructure and prevention strategies; for mixed plans, authority participation and a framework agreement; for individual plans, only the general and private elements; and for collective plans, participation of all parties involved, adhesion mechanisms, communication, and also a framework agreement.
For a manufacturing site or a group with several plants in Mexico, the modality choice matters beyond paperwork: an individual plan is faster to file but only covers that one site, while a collective plan lets several facilities, or a group of companies in the same value chain, share the same registered plan and the same waste manager relationship, at the cost of the extra framework-agreement and adhesion requirements.
Common mistakes
- Confusing special management waste with hazardous waste, which leads to filing the plan with the wrong authority.
- Applying one category's threshold to another: using the 10-tonne federal transport criterion for treatment sludge, which requires 100 tonnes, or vice versa.
- Forgetting criterion 6.3 and assuming that fitting the general definition is enough, without checking that the waste is in the state diagnosis or backed by the company's own technical-economic study.
- Not separating general elements from additional ones based on the plan's modality, which produces incomplete plans that the state authority sends back for correction.
- Filing the plan only with the state when the operation is national or regional and should therefore also have been filed with SEMARNAT.
A well-built management plan doesn't replace the Annual Operations Report (COA), the report to the Pollutant Release and Transfer Register (RETC), or the Single Environmental License when a facility requires it: these are separate filings that tend to ask for similar data, and it's worth keeping them consistent with each other so an inspector doesn't find a waste figure that doesn't match between documents.
Frequently asked questions
What's the difference between special management waste and hazardous waste?
Special management waste is what doesn't meet the characteristics to be considered hazardous or municipal solid waste; it's typically generated in production processes. Hazardous waste has a separate, stricter regime, under SEMARNAT's jurisdiction.
From what quantity do I need a management plan?
It depends on the category: NOM-161's annex sets 10 tonnes a year for federal transport and department stores, 100 tonnes a year for treatment sludge, and 80 cubic metres for construction waste. If your waste is, by nature, municipal solid waste, the LGPGIR's general large-generator threshold is 10 tonnes a year.
Where do I file the management plan?
With the state where the plan will be implemented. If the modality is national or regional, it must also be filed with SEMARNAT.
What if my management plan is individual rather than collective?
You only need to include the general elements from section 9.1 and the private elements from 9.2, without the joint-participation or framework-agreement requirements that collective or mixed plans do require.
Does the management plan replace registering with the RETC?
No. They're separate filings, even though they ask for related information. An approved management plan doesn't exempt a company from reporting to the RETC or filing the Annual Operations Report when required.
Does a management plan have a fixed validity period?
NOM-161 doesn't set a single validity period applicable to every plan in its text: that depends on the conditions the state sets when registering it. It's worth confirming directly with the state authority when filing the plan, rather than assuming a standard term.
Can several plants share one management plan?
Yes, through the collective or mixed modalities, which are built for that: they add participation, adhesion and framework-agreement requirements that an individual, single-site plan doesn't need.
Classifying the waste correctly and documenting the plan from the start avoids being sent back by the state authority and figures that don't match across filings. Our waste management solution helps keep that data organised, with its supporting document, from the diagnosis through to reporting.
