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Environmental Health & Safety
Hazardous Waste Management Manual - Waste Management


Each year the NMSU EH&S manages approximately 35,000 pounds of hazardous waste and surplus chemicals collected from laboratories, workplaces and stockrooms on campus and other outlying NMSU facilities.

NMSU generates and manages hazardous wastes at established sites on campus. The materials are received by EH&S at the laboratory or campus workplace and transported to a staging area on A mountain 

The tracking form attached to each container sent for disposal has a tracking number which is used to ensure that the material is accounted and disposed of properly. An EPA Uniform Hazardous Waste Manifest  is then generated and the containers are segregated and re-packaged. Each chemical container is placed in any of four major categories: non-hazardous waste, redistribution program, recycling, or storage for eventual commercial disposal at an EPA approved facility.

Storage for commercial disposal is handled by either placing the chemical on a shelf in cabinets according to its hazard class or by bulking with other compatible chemicals. Bulking of chemicals is one of the disposal cost reduction measures utilized by EH&S .

Chemicals disposed of through commercial hazardous waste vendors are either incinerated, fuel-blended for energy recovery, or treated to meet EPA mandated standards prior to secured landfilling. Biological, radiological and special waste are also collected, tracked and sent for proper disposal. 


Hazardous Chemical Waste

The 1976 Resource Conservation and Recovery Act (RCRA), Part 261, Subpart C provides the definition of hazardous (chemical) waste for which EPA has issued regulations.  Generally the identification of hazardous waste can be determined if the material is included in either of two categories -- it is either a characteristically hazardous waste or it is listed hazardous waste

The waste is considered hazardous if due to its quantity, concentration, or physical and chemical characteristics may

  • cause, or significantly contribute to, an increase in mortality or an increase in serious or incapacitating illness; or

  • pose a substantial present or potential threat to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed.

The disposal of regulated waste and other unwanted chemicals has become increasingly complicated. The U.S. Environmental Protection Agency and the New Mexico Environmental Division oversee the accumulation, treatment and disposal of regulated wastes in New Mexico. This section will provide a better understanding of materials that are regulated.   Ideally the generator will use this information to design experiments with waste minimization in mind, and dispose of chemical waste in a manner consistent with legal requirements.  


Characteristically Hazardous Waste

The Code of Federal Regulations (40 CFR 261.20 - 261.24) and RCRA define the four fundamental characteristics of regulated hazardous waste as:  ignitability, corrosivity, reactivity, and toxicity characteristics.

A waste demonstrating any of these characteristics is a hazardous waste whether it is listed or not

Ignitability - Ignitable wastes are spent materials exhibiting one or more of the following characteristics:
  • Liquids that have a flash point less than 60C (140F) other than aqueous solutions containing less than 24% alcohol by volume.
  • Materials other than liquids that are capable, under standard temperature and pressure, of causing fire by friction, adsorption of moisture, or spontaneous chemical changes and, when ignited, burn so vigorously and persistently that they create a hazard.
  • An ignitable compressed gas, including those that form flammable mixtures with air.
  • Oxidizers that stimulate combustion of organic materials.

Examples - most common organic solvents, gases such as hydrogen and hydrocarbons, and certain nitrate salts.

Corrosivity - Corrosives are materials meeting one or more of the following criteria:

  • Aqueous solutions with a pH of less than or equal to 2 or greater than or equal to 12.5.
  • Liquid substances which corrode steel at a rate greater than 6.35 millimeters (0.250 inches) per year at a test temperature of 55C (130F).

Examples - Most common laboratory acids and bases as well as some amines and solutions of certain metal salts (e.g., a 0.1M aqueous solution of ferric chloride has a pH of 2.0).

Reactivity - Reactive materials are defined as materials meeting one or more of the following criteria:

  • Is normally unstable or reacts violently (without detonating).
  • Reacts violently with water.
  • Forms explosive mixtures with water..
  • Materials which, when mixed with water, generate toxic gases, vapors, or fumes dangerous to human health or the environment.
  • Contains cyanide or sulfide and generates toxic gases, vapors or fumes between pH 2 and 12.5.
  • Materials capable of detonation or explosive reaction when subjected to a strong initiating source or if heated in confinement.
  • Capable of detonation or explosive decomposition at standard temperature and pressure.

Examples -Alkali metals, peroxides, and cyanide and sulfide compounds.

Toxicity - Toxicity is established through the Toxicity Characteristic Leaching Procedure (TCLP), which measures the tendency of certain toxic materials to be leached (extracted) from the waste material under conditions that the waste would be exposed to in a landfill. A waste demonstrates a TCLP characteristic if a representative sample taken according to prescribed EPA extraction procedure contains any of the following substances in excess of concentration limits.

  • Arsenic
  • Barium
  • Benzene
  • Cadmium
  • Carbon tetrachloride
  • Chlordane
  • Chlorobenzene
  • Chloroform
  • Chromium (hexavalent
  • o-Cresol
  • m-Cresol
  • p-Cresol
  • 2,4-Dichlorophenoxyacetic acid
  • 1,4-Dichlorobenzene
  • 1,2-Dichloroethane
  • 1,1-Dichloroethylene
  • 2,4-Dinitrotoluene
  • Endrin
  • Heptachlor (and its epoxide)
  • Hexachlorobenzene
  • Hexachlorobutadiene
  • Hexachloroethane
  • Lead
  • Lindane (hexachlorocyclohexane)
  • Mercury
  • Methoxychlor
  • Methyl ethyl ketone
  • Nitrobenzene
  • Pentachlorophenol
  • Pyridine
  • Selenium
  • Silver
  • Tetrachloroethylene
  • Toxaphene (chlorinated camphene)
  • Trichloroethylene
  • 2,4,5-Trichlorophenol
  • 2,4,6-Trichlorophenol
  • 2-(2,4,5-Trichlorophenoxy)propionic acid (Silvex)
  • Vinyl chloride

The levels at which these chemicals are regulated varies from 0.2 ppm to 400 ppm.  These levels are very low.  If a waste contains one or more of these components it should be considered to be hazardous waste unless TCLP analysis shows it to be below the regulatory limit.

The eight metals listed here are regulated in both their pure forms and as compounds (e.g. lead, lead paint, lead oxide, and tetraethyl lead are all regulated wastes). 



Listed Hazardous  Waste

In addition to characteristics waste, RCRA also lists (codes) certain specific waste materials as being regulated. These materials are listed in 40 CFR sections 261.31 (the F List), 261.32 (the K list), and 261.33 (the P and U Lists).

F List - the F List addresses wastes from nonspecific sources (e.g., spent solvents) and is broken down into several subcategories (or codes). Five codes that are commonly applicable to laboratory wastes are:

  • F001 Code - spent solvent mixtures and blends used for degreasing which contained, before use, a total of ten percent or more (by volume) of one or more of the following halogenated solvents:
    • tetrachloroethylene
    • methylene chloride
    • trichloroethylene
    • 1,1,1-trichloroethane
    • carbon tetrachloride
    • chlorinated fluorocarbons
  • F002 Code - spent solvent mixtures and blends which contained, before use, a total of ten percent or more (by volume) of one or more of the following halogenated solvents:
    • tetrachloroethylene
    • methylene chloride
    • trichloroethylene
    • 1,1,1-trichloroethane
    • chlorobenzene
    • 1,1,2-trichloro-1,2,2-trifluoroethane
    • ortho-dichlorobenzene
    • trichlorofluoromethane
    • 1,1,2-trichloroethane
  • F003 Code - spent solvent mixtures and blends which contained, before use, a total of ten percent or more (by volume) of one or more of the following non-halogenated solvents:
    ethyl ether
    • xylene
    • acetone
    • ethyl acetate
    • ethyl benzene
    • methanol
    • methyl isobutyl ketone
    • n-butyl alcohol
    • cyclohexanone
  • F004 Code - spent solvent mixtures and blends which contained, before use, a total of ten percent or more (by volume) of one or more of the following non-halogenated solvents:
    • cresols and cresylic acid
    • nitrobenzene
  • F005 Code - spent solvent mixtures and blends which contained, before use, a total of ten percent or more (by volume) of one or more of the following non-halogenated solvents:
    • toluene
    • methyl ethyl ketone
    • carbon disulfide
    • isobutanol
    • pyridine
    • benzene
    • 2-ethoxyethanol
    • 2-nitropropane

K List - this list contains waste from specific sources such as factories or industries.  These definitions are generally not applicable to wastes generated at NMSU.

P List - this list covers acutely hazardous wastes The criteria for this listing are as follows:

  • Small doses cause human mortality.
  • Oral LD50 = < 50 ppm by weight (mg/Kg).
  • Inhalation LC50 = < 2 mg/L.
  • Dermal LD50 = < 200 mg/Kg.

The list is applicable to some used chemicals that are disposed of by NMSU laboratories and research areas.

Examples - nickel tetracarbonyl, phosphine, and osmium tetroxide.

U List - This list addresses used and unused hazardous materials that are toxic. 

Like the P list, this is applicable to many used and surplus chemicals that are disposed of by NMSU laboratories and research areas.

Examples - aniline, benzene, and acetone.

Questions as to the determination of hazardous chemical waste beyond those covered here should be directed to EH&S at 646-3327.  


Hazardous Biological (or Biohazardous) Wastes

Certain biological (or biohazardous) waste has been identified by the New Mexico Board of Health as waste which requires special handling to protect human health or the environment. It includes solid waste which if improperly treated or handled may serve to transmit an infectious disease(s). Biological waste is regulated by the New Mexico Environmental Division (NMED) and the New Mexico Department of Health. This waste is comprised of the following:


Microbiological waste includes discarded:
  • cultures and stocks of infectious agents and associated biologicals; specimens from medical, pathological, pharmaceutical, research, clinical, commercial, and industrial laboratories;
  • live and attenuated vaccines, used disposable culture dishes; and
  • used disposable devices used to transfer, inoculate, or mix cultures.
Animal Animal waste includes:
  • animal carcasses;
  • animal body parts;
  • whole blood, serum, plasma, and/or other blood components from animals; and
  • bedding of animals intentionally exposed to pathogens.
Blood Products Human blood and blood products include:
  • human blood, serum, plasma, other blood components, and body fluids; and
  • disposable items contaminated with human blood or body fluids.
Pathological Pathological waste includes but is not limited to:
  • human materials including: body parts, tissues or fetuses, organs, and bulk blood and body fluids;
  • laboratory specimens of blood and tissue after completion of laboratory examination; and
  • anatomical remains.
Sharps Sharps include the following, regardless of contamination:
  • hypodermic needles;
  • hypodermic syringes with attached needles;
  • scalpel blades;
  • razor blades, disposable razors, and disposable scissors used in surgery or other medical procedures; and
  • glass Pasteur pipettes.

Sharps include but are not limited to the following, when contaminated, i.e. the presence or reasonably anticipated presence of blood, body fluids, or other infectious materials. 

  • glass pipettes;
  • broken glassware;
  • specimen tubes;
  • blood culture bottles; and
  • microscope slides.
Also see Appendix -Accumulation procedures - biological waste    


Radioactive Wastes

Radioactive Waste determination and disposal are coordinated in accordance with local, state and federal regulations.

Radioactive waste is required to be labeled in accordance with procedures established by the Radiation EH&S r and typically exhibits the universal radiation precaution symbol for radiation. Radioactive waste generated at NMSU is usually limited to low-level radioactive waste from the use of by-product material and naturally occurring or accelerator-produced radioactive material (NARM).

General laboratory refuse

This would include gloves, glassware, paper, plastic, etc. that are contaminated with radioactive materials.

Liquid wastes

Waste liquidswhich include a radioactive material component,

Animal   waste

The remains of animals that contain radioactive materials as a result of administration of such material for research.

By-product rad material 

By-product material, as defined by the U.S. Nuclear Regulatory Commission (U.S. NRC), is reactor-produced radioactive material and includes most purchased radiolabelled chemicals. The use and disposal of by-product material are regulated by the U.S. NRC and usually require a license

NARM  Naturally occurring or accelerator-produced radioactive material includes uranium and thorium salts.

Common waste management methods for low-level radioactive waste from laboratories include storage for decay and indefinite on-site storage, burial at a low-level radioactive waste site, incineration, and sanitary sewer disposal. For further information regarding the University's radiation safety and radioactive waste program, please refer to Radiation Safety Manual.



Other Regulated, Non-RCRA and Special Wastes

Allowable Wastewater Discharge   Other regulated waste include the wastewater discharged by NMSU. The Las Cruces Wastewater Authority allows the discharge of the following::

See the NMSU sewage discharge limits to LC (appendices).

Restricted wastewater.  The following may not be discharge as waste water a_const_spin.gif (4551 bytes)

Special landfill and other waste   Special landfill wastes are wastes which are regulated by the New Mexico Environmental Division. They are not considered hazardous by the EPA definition, but must be disposed of at a permitted landfill. Examples include asbestos, soils contaminated by petroleum hydrocarbons, and used oil.  See the accumulation section on special waste handling.



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