Chemical Waste


Personnel who use chemicals as part of their jobs follow protocols to prevent exposure and minimize the potential for spills and incidents. Personal Protective Equipment (PPE) such as gloves and eye protection can protect workers from splashes and contact hazards, fume hoods can eliminate the risk of inhaling harmful chemicals, and storage cabinets can mitigate the risk of fires and spills.

There is another facet of chemical safety which must be managed, however, and that is protecting the environment from chemical contamination. Improper or careless disposal practices have significant effects on our environment, including polluting water sources, poisoning wildlife, and creating toxic sites which aren’t suitable for animal or human habitation. For employees who work with chemicals (and therefore generate chemical wastes) the single most important ‘green’ activity is conscientious, careful management of chemical wastes.

In order to protect the environment, governments have created very strict regulations governing chemical waste management. The only way to ensure such regulations are followed is to accompany them with severe penaltiesfor non-compliance.

The guidance that follows is intended to provide employees with the information they need to properly manage chemical wastes. It is up to each user of chemicals to understand and follow the rules. Together we can protect the environment and protect the University from costly fines and penalties.



It doesn’t matter where you work; in a laboratory, in a mechanical room, or anywhere else. Chemical waste rules must be applied in the same manner across all workplaces. Most chemical wastes are generated in laboratories but many are generated outside of laboratory settings; contaminated soils, building materials, lubricants, paints and many other materials can fall under these rules.

Waste Chemicals:

The information that follows in this document applies only to chemical wastes. Chemicals that are going to be used in a process or experiment must be managed safely; however if they are not wastes then the information that follows does not apply. Keep in mind that just because a chemical is unused, doesn’t necessarily mean it is not a waste. For example:

  • Expired Materials: if a chemical bottle has an expiration date that has passed, and that chemical cannot be used when it’s expired, then it is a waste.
  • Extraneous Materials: if the process or experiment for which a chemical is used is no longer practiced, and that chemical will not be used for another purpose, that chemical is a waste. Some examples include:
    • When a researcher leaves, and leaves behind chemical bottles for experimentation that no longer occurs, or
    • Containers of oil for a piece of equipment that has been removed.

Once you’ve determined that a chemical is not useful – for any reason – then the information in this document applies and decisions about waste management must be made.


It doesn’t matter how much waste you are generating: 1 ml is regulated the same as 1 gal when it comes to chemical waste.

Classification of Chemical Waste

The next step after identifying a chemical as a waste is to classify that waste. Chemical wastes will ultimately fall into one of 4 management categories:

  • Collected as a Hazardous Waste: A chemical which exhibits a ‘hazardous’ characteristic, is listed according to Federal or State regulation, or best management practices dictate strict control must be managed as a hazardous waste. Most of the information in this document describes the rules to follow when managing hazardous wastes.
    • Hazardous wastes have the greatest potential to harm people or the environment, and bear the full burden of environmental regulation.
    • Mis-management of hazardous wastes can result in significant environmental penalties and enforcement actions.
    • The term ‘hazardous waste’ should only be used when describing chemicals. Infectious or radioactive wastes are not ‘hazardous wastes’ unless they are mixed with chemical wastes.
    • Hazardous wastes are generated routinely at Boston University.
    • Collection and management of chemical wastes as hazardous wastes ensures the maximum level of environmental protection and is the safest means of chemical waste management.
  • Collected as a Non-hazardous Waste: A chemical which does not exhibit a state or federal hazardous characteristic and isn’t listed as a ‘hazardous waste’ isn’t necessarily safe for disposal via sink or in the regular trash.
    • In some cases, protection of the environment requires us to go above and beyond the hazardous waste regulations. An example would be ethidium bromide, which doesn’t technically exhibit a hazardous characteristic but which isn’t safe for handling as regular trash. Other examples include materials like nanoparticles for which comprehensive safety information does not yet exist. Often the
      precautionary principle dictates that we collect these materials because we do not understand the potential harm they can cause in the environment.
    • In other cases, a different regulation might stipulate collection of a waste chemical. An example would be very small concentrations
      (part-per-billion level) of mercury in otherwise benign reagents. Local Clean Water Act enforcement prohibits mercury disposal to sink drains even though the level of contamination is low.
    • In cases where a chemical is collected as a non-hazardous waste, some of the hazardous waste management rules do not apply.
  • Collected as a Waste: A small subset of chemical wastes have been de-regulated to some extent based on the fact that they are so widespread.
    • Management regulations still exist, but they are lessened relative to hazardous waste regulations.
    • Universal wastes are most often generated and managed through Facilities Management Department operations.
    • Universal Wastes include:
      • Fluorescent bulbs of all shapes and sizes
      • Many types of batteries
      • Mercury-containing devices such as switches and thermostats.
    • Boston University has a separate policy detailing how Universal Wastes must be managed.
  • Safe for Sink or Trash disposal: A very small percentage of chemical wastes are un-regulated and safe to pour into sinks or place in the trash. Some examples include benign salts like sodium chloride, and non-toxic, non-corrosive cleaning chemicals. Contact EHS prior to disposing any chemical into a sink or via the trash.

Hazardous Wastes

The most important question to answer when managing a chemical waste: “does my chemical waste have to be collected and managed as a hazardous waste?” It is necessary to know the answer to this question as this is the first step in a process known as making a ‘waste determination’, and is a required step in chemical waste management.

In order to determine whether a chemical waste must be collected as a hazardous waste you must have information about the properties and behavior of the chemical. This knowledge is fundamental to safe laboratory operations, and literature is available in your workplace in the form of Safety Data Sheets (SDS or MSDS) which can help. If you don’t know or are unsure about the characteristics or properties of a chemical waste contact EHS for assistance.

Never assume a chemical waste is safe for disposal in the regular trash or via a sink or drain. Always err on the side of caution; collection and management as a hazardous waste because this is the safest and most responsible way to collect a chemical waste.

A chemical waste must be classified and managed as a hazardous waste if it exhibits any of the four characteristics described below, or is specifically listed in the regulations.

Ignitable Characteristic

A chemical waste is a hazardous waste due to ignitability if:

  • Liquid Chemicals: the flash point of the liquid chemical is less than or equal to 140 degrees F.
    • Equivalent is 60 degrees C
    • Flashpoint determination is ‘Pensky-Martens Closed Cup Tester’
    • Common examples include:
      • Alcohols (note: for ethanol, mixtures greater than or equal to 20% are hazardous wastes. For other alcohols the cut-off is 10%.)
      • Organic Solvents and mixtures containing organic solvents such as xylenes, hexane, toluene, acetone, etc.
      • Stains and mixtures containing stains (because they are solvent-based).
      • Oil-based paints and coatings
  • Solid Chemicals: the chemical is capable, under standard temperature and pressure, of causing fire through friction, absorption of moisture or spontaneous chemical changes, and burns vigorously when ignited
    • Common examples include:
      • Paraformaldehyde
      • Parafin wax with xylene
      • Rags saturated with an ignitable liquid
  • Compressed Gas: Ignitable compressed gases must also be managed as hazardous wastes.
    • Generally this involves partially-full, or left-over cylinders of gas
    • Common Examples include:
      • Hydrogen
      • Acetylene
      • Propane
      • Butane
  • Oxidizers: the chemical is capable of enhancing the combustion of other materials, generally by yielding oxygen.
    • Common examples include:
      • Chlorates
      • Chlorites
      • Nitrates
      • Perchlorates
      • Perchlorites
      • Permanganates
      • Peroxides

If your chemical waste exhibits any of the ‘ignitable’ characteristics above, you must manage it as an ignitable hazardous waste.

Corrosive Characteristic

A chemical waste is a hazardous waste due to corrosivity if:

  • It is aqueous and has a pH less than or equal to 2, or greater than or equal to 12.5, or
  • It is a liquid and corrodes steel (Type SAE 1020) at a rate greater than 6.35 mm (approximately 0.250 inch) per year.
  • Common examples include:
    • Hydrochloric Acid
    • Sulfuric Acid
    • Nitric Acid
    • Sodium Hydroxide

Reactive Characteristic

A reactive hazardous waste is defined as a material which:

  • Under normal conditions is unstable and can undergo violent changes without detonating
  • Reacts violently with Water
    • Common Examples Include:
      • Sodium metal,
      • Anhydrides,
      • Sodium Borohydride
  • Reacts violently with Air
    • Common Examples Include:
      • tert-butyllithium,
  • Capable of detonation or violent explosion
    • Common Examples Include:
      • Dry picric acid,
      • Azide compounds,
      • Organic peroxides,
      • Old ether or tetrahydrofuran with peroxide formation
  • A cyanide or sulfide which, when exposed to a pH of between 2 and 12.5, generates toxic gases, vapors or fumes
    • Common Examples Include:
      • Sodium cyanide,
      • Potassium cyanide,
      • Sodium sulfide,
      • Carbon disulfide


The toxic ‘characteristic’ is where the regulations start to get into listing specific chemicals. To determine whether a chemical waste exhibits the toxic characteristic, it is necessary check the federal toxic list, known as the ‘D’ list. The state of Massachusetts adds some chemicals to the list as well.

As a general rule, a waste that contains any material on this list should be collected for disposal regardless of concentration; even if it’s not technically regulated as a hazardous waste it still doesn’t belong in the environment.

The concentration listed next to the chemical names below refers to a very specialized analytical method known as the TCLP test (the Toxic Characteristic Leachate Procedure). The TCLP test is designed to simulate the concentration of contaminant that would leach out of the material if it were in a landfill under acid rain conditions. EHS can provide TCLP analysis if necessary. However, in most cases the right thing to do is to collect wastes with any concentration of the chemicals listed below. As always, contact EHS if you have questions.