Hazardous Waste Disposal Guide

Any chemical that exhibits hazardous characteristics as defined by federal and Illinois rules and regulations, is unusable or unwanted in any way and poses a potential hazard to individuals, the environment or public health is a chemical waste.

Examples:

• Waste and opened surplus chemicals
• Expired or off -specification chemicals
• Carcinogens and cytotoxic (antineoplastic) agents
• Prescription drugs and controlled substances
• Empty chemical drums and other chemical containers with a capacity of 10 gallons and greater
• Thermometers and other items containing mercury
• Non-returnable gas cylinders and lecture bottles or pressurized chemicals
• The residue of spill clean-up materials-contaminated rags and absorbents
• Non-radioactive lead shielding, lead blocks and lead scrap
• Photographic film processing solutions
• Used oil—motor, vacuum pump, lubricating oils, etc.
• Pesticides
• Used solvents
• Batteries
• Paint, paint thinners, brush cleaners, linseed oil, thinner contaminated rags
• Heavy metal-containing waste or products (arsenic, barium, cadmium, chromium, lead, mercury, selenium and silver)

The Radiation Safety Handbook contains definitions and disposal procedures for radioactive waste.

Naturally-Occurring-Radioactive-Materials (NORM) for example uranium, thorium and samarium compounds must be disposed of through the radioactive waste program.

The definitions and disposal procedures for potentially infectious waste can be found on the Hazardous Waste page.

The Environmental Protection Agency’s (EPA) policy for hazardous waste management prioritizes waste minimization. The University must annually report to the government on its efforts to reduce hazardous waste.

Waste minimization is any action that:

• Decreases the amount of hazardous waste generated
• Reduces the inherent toxicity of the waste

The costs associated with properly disposing of chemical wastes and safely storing chemicals in the research laboratory are inextricably linked. Researchers are encouraged to limit the number and type of chemicals purchased whenever possible. Ordering additional chemicals is easier than disposing of unwanted or unused surplus chemicals. 

REMEMBER: The disposal cost can exceed ten times the cost of the chemical.

In some cases, there are no acceptable waste disposal options.

Rethink how you purchase, handle and store laboratory chemicals to control the increasing costs of proper chemical waste disposal and the inherent hazards of storing and working with hazardous chemicals.

Waste minimization benefits you, the university, and the environment by:

• Significantly lowering costs
• Reducing potential health hazards
• Reducing potential long-term liabilities for disposal
• Promoting environmental ethics
• Preventing pollution

It is the responsibility of every investigator who generates waste to incorporate the principles of waste minimization into experimental design.

• Substitute less hazardous chemicals whenever possible.
• When planning experiments or demonstrations, examine all wastes generated and ask if they could be minimized and how.
• Reduce the scale of processes so that less waste is generated.
• Minimize the volume of waste solutions containing mercury and heavy metals.
• Mark the contents of all chemical containers to prevent the generation of unknowns.
• Actively manage the inventory of all hazardous materials used in your laboratory or work location. ChemTracker is a free chemical inventory program for all Northwestern University research groups with Lumen profiles.
• Ask others in your department if they could use your unwanted chemicals.
• Neutralize, quench or destroy hazardous by-products as the last step in experiments.
• Separate halogenated from non-halogenated solvents. The non-halogenated solvent waste may be shipped for fuel blending.
• Separate aqueous and solvent wastes if possible.

When in doubt, call Research Safety for assistance.

Northwestern University manages all hazardous waste following federal, state, and local regulations. Disposal procedures for specific waste streams generated in nonlaboratories are outlined in Appendix D.

For laboratory hazardous waste, Northwestern University elected coverage under Subpart K: Alternative Requirements for Hazardous Waste Determination and Accumulation of Unwanted Material for Laboratories Owned by Eligible Academic Entities¹.

Northwestern University is an eligible academic entity as defined in 35 IAC 722.300. Only the laboratory facilities that generate hazardous wastes under the following generator identification numbers are included in the Subpart K² election:

   ILT180011553
   ILD982646721
   ILO000040436,
   ILT180011546.

Hazardous wastes generated through facilities under these identification numbers are not part of the Subpart K election.

Part I

Northwestern University uses the term “chemical waste” on laboratory containers as an equally effective term instead of “unwanted material”. “Chemical waste” generated in the eligible laboratories has the same meaning as the term “unwanted material”, and the material is subject to the same requirements as if it were called “unwanted material”. The “chemical waste” terminology is consistent with the existing hazardous waste program of the University.

Laboratory containers are labeled and content records are logged to impart information “associated with the container”. Laboratory workers complete and submit a Hazardous Waste Pickup Request online (Lumen) when a container is ¾ full or has reached 150 days since the start date of accumulation. This Guide's “Chemical Waste Disposal Overview” presents detailed chemical waste procedures.

A Hazardous Waste Professional will remove chemical waste containers from each eligible laboratory no greater than six (6) months of each container’s accumulation start date.

Part II

Labeling

Northwestern University uses the term “chemical waste” on laboratory containers. In addition, the prescribed labeling protocol is the name or description of chemical contents or composition of the chemical waste (if known, product(s) of chemical reaction). Each container is also labeled with the date on which the chemical waste first began accumulating in the container. Laboratory workers who add the chemical waste to existing laboratory containers log the relative information on the label.

This information is used in the determination of the status of the chemical waste as a solid waste and a hazardous waste.

Management

Laboratory containers are maintained in good condition and kept always closed, except when adding, removing, or bulking chemical waste. If a container is damaged, it will be replaced, repaired, or over packed.

Laboratory containers are compatible with their contents; they are made of, or lined with, a composition material that is compatible with the chemical waste.

Training-Laboratory Workers

Northwestern University provides training to all individuals working in the laboratories that is commensurate with their duties. Lab workers must complete the Hazardous Chemical Waste Management Training, which includes information on Subpart K implementation.

Training-On-site Transfers

In addition to the training for laboratory workers, Northwestern University provides training to all applicable Hazardous Waste Professionals on Subpart K.  Northwestern University considers Hazardous Waste Professionals “trained professionals” as defined in Subpart K.

Removal of Chemical Waste

A Hazardous Waste Professional removes containers of chemical waste from each eligible laboratory no greater than six (6) months of each container’s accumulation start date.

In general, laboratories accumulate no more than 25 gallons of chemical waste (total, per laboratory) and no more than one (1) quart of reactive acutely hazardous chemical waste prior to removal from the laboratory.

Reactive acutely hazardous chemical wastes are P-listed wastes signified as reactive.

 Table 5.0

Laboratory workers complete and submit a Hazardous Waste Pickup Request online (Lumen)when a container is ¾ full or has reached 150 days since the start date of accumulation.

Total chemical waste stored in any one laboratory is checked regularly. Lab workers follow this procedure should the total volume of chemical waste reach the storage limit:

• Mark on all contributing containers the date on which the 25-gallon or one-quart applicable volume was exceeded
• Complete and submit the Hazardous Waste Pickup Request online (Lumen)
• Once a request has been submitted, pick up by a Hazardous Waste Professional will occur within three (3) business days.

Hazardous Waste Determination

Lab workers first classify chemical waste within the laboratory. A Research Safety Hazardous Waste Team member transfers the chemical waste directly from the laboratory to the on-site central accumulation area. The hazardous waste determinations are made within four (4) calendar days of arrival at the on-site central accumulation area.

If the Research Safety Hazardous Waste Team member characterizes the chemical waste as hazardous, the container is labeled “hazardous waste”. All applicable rules for the shipping container also apply.

Laboratory Clean-outs

Northwestern University intends to use something other than the incentives for laboratory clean-outs provided in 35 IAC 722.313.

Emergency Prevention

Northwestern University is committed to safely and properly disposing of all its hazardous wastes. Moreover, the University is committed to promoting waste minimization and pollution prevention in activities. The section “Reporting Inappropriate Disposal of Potentially Hazardous Chemicals” presents the Research Safety statement of intent to disopse of hazardous waste safely and properly.

This guide includes an Emergency Contact List that provides contact information for the University’s emergency coordinators and internal response contacts; external response contacts for federal, state, and local agencies; and spill response contractors.

Availability

This Laboratory Management Plan section is available to laboratory workers, students, and others who may request it.

Review

Northwestern University will review and revise this Laboratory Management Plan as needed: when new waste streams are introduced, when the Hazardous Waste Disposal Guide is reviewed and revised, or when prompted by disposal circumstances.

• Collect chemical waste in sturdy leak-proof containers.
  
  • Keep hazardous chemicals away from sinks or surrounding areas to prevent fugitive releases.
  • Do not dispose of hazardous chemicals via the sink, as non-hazardous trash or as biological Waste or radioactive waste.
  • Evaporation is not an acceptable waste disposal method. The only exceptions are insignificant, residual amounts of liquid associated with lab ware or containers.
  • Do not mix radioactive materials with chemical waste.
• Always label and seal chemical waste containers.
  • Complete and attach a Chemical Waste Label (as seen in Appendix A) for any unlabeled waste containers.
  • Always enter an accumulation start date.
  • Identify all constituents by chemical name. No abbreviations, trade names, or chemical formulas!
  • List the concentration of constituents.
  • Chemical waste, radioactive waste and biological waste have unique labels.
• Store waste containers properly.
  • The caps must be tight. No open funnels or filling aids may be left in containers.
  • Process waste containers (i.e., HPLC, photographic solutions) must have a cap with atight fitting hole for the fill tube during waste collection.
  • Never store flammable waste with waste containing oxidizers. Flammable wastes are best stored in a fire-rated cabinet (UL or FM certified).
  • Use bins to segregate acidic from caustic waste streams and to provide secondary containment. Segregate nitric acid waste containers from organic waste containers.
  • As a last step of a research project quench potassium or pyrophoric potassium alloys (NaK) in the lab.
  • Let etch and cleaning solutions (i.e., piranha, aqua regia).cool down to room temperature and use a vented cap.
• Request a non-laboratory waste container pick up in 60 days or when a container is ¾ full through hazardous-waste@northwestern.edu.
• Request a laboratory chemical waste container pickup in 150 days or when a container is ¾ full.
  • Fill out and submit a Hazardous Waste Pickup Request online (Lumen). Once a request has been submitted, pick-up will occur within three (3) business days.

Other Reminders

Never abandon chemicals. Contact Research Safety immediately for proper disposal.

Always wear eye/face protection, a lab coat and appropriate chemically resistant gloves when working with hazardous chemicals.

Consult Safety Data Sheets (SDS) for more information on hazardous chemicals you may work with at Northwestern University.

Regulations define any location where small amounts of chemical waste are temporarily stored as a “Satellite Accumulation Area” or SAA. To be considered an SAA, waste must be stored at or near the point where the waste is generated.

SAAs in laboratories may contain at most 25 gallons of chemical waste. In non-laboratory areas the limit is 55 gallons. Keep accumulated waste volumes to a minimum – request routine waste pickups.

Lab chemical waste accumulation areas may be inside a chemical fume hood or on a laboratory benchtop.

NOTE: Waste handling and SAAs may not be near open sinks or floor drains!

SAAs outside of laboratories must be posted with a sign). SAAs must be provided with secondary containment.

Incompatible wastes must be separated by storing wastes in separate containment bins, or if appropriate, in separate areas within the lab. Contact Research Safety if you have any questions regarding the incompatibility of waste streams, especially waste containing nitric acid and etching solutions.

Appropriately size waste containers!

All chemical waste containers must be:

• Properly labeled (See example label in Appendix A.) Package small containers so a fully completed label is securely attached.
• Closed and sealed except when adding contents; and

ORIGINAL CONTAINER

Submit for disposal in the original labeled container. Do not deface any manufacturers’ labels.

CONTAINER OTHER THAN THE ORIGINAL CONTAINER

Deface the existing label or mark “XXX” through the existing label.

CARBOYS (LARGE VOLUMES OF LIQUIDS)

Separately collect mercury or other heavy metals containing solvents. Separate aqueous waste, halogenated and non-halogenated solvents.

1. Use 5 gallon carboys only if they can be filled within 60 days.
2. Complete the carboy tag. Each time you add waste to the container, note this on the waste tag. Use a pencil; ink will smudge.
3. Fill the container no more than ¾ full. DO NOT OVERFILL.

BAGGED WASTE (CHEMICALLY CONTAMINATED SOLID WASTE NO SHARPS)

1. Line a five-gallon pail with a clear plastic bag. The lid must be on the pail except when adding contents to the bag.
2. When bag is ¾ full, close bag with tape or zip tie. Complete and attach a Chemical Waste Label to the bag. NOTE: Never use black plastic or biohazard bags to collect chemical wastes!
3. Obtain a one-gallon or smaller size plastic container with lid from the Scientific Stockrooms for smaller solid waste volumes. Label the outside of the container with a completed Chemical Waste Label.

SHARPS CONTAINER (CHEMICALLY CONTAMINATED)

Dispose of chemically contaminated broken glass and pipette tips in labeled puncture resistant containers. Segregate contaminated needles and blade wastes in a labeled yellow sharps container available in the Scientific Stockrooms.

Put potentially infectious sharps only into a red sharps container. See Biological/Infectious Waste.

EMPTY HAZARDOUS CHEMICAL CONTAINERS

1. Thoroughly empty all contents. Only de minimis³ amounts of the hazardous chemical may remain before rinsing. Collect all triple rinsate as chemical waste.
2. Obliterate, remove, or thoroughly deface labels before disposal.
3. Place rinsed and dried glass in the glass disposal container, or affix a recycling sticker and place it in the hallway.

If the chemical containers have a capacity of >10 gallons or contain solids, or if sludge remains, submit them as chemical waste.

Manufacturer septum caps on empty septum-sealed containers (such as Sure/SealTM bottles) may be removed and the containers subsequently rinsed and disposed of only if safe.  Empty septum-sealed containers that hold inherently dangerous or air-reactive substances, such as pyrophoric or acutely toxic chemicals, should be disposed of as chemical waste with their septum caps intact.

In the laboratory, hazardous chemicals can be divided into four general hazard categories – corrosives, flammables, reactives, and toxics. In most cases, the immediate or obvious hazard determines which category a particular chemical is classified. See the Laboratory Safety and Chemical Hygiene Plan for further definitions.

Note: Highly toxic gases and SELECT AGENTS are restricted commodities requiring purchase approval from Research Safety.

Below are some general principles to follow when handling and storing chemicals:

General Principles for Managing Laboratory Chemicals

• Less is better. Purchase small amounts that you will use up within a year. Whereas the per-unit cost may be greater—significant savings are realized in reduced disposal costs and safer storage.
• Buy pre-made molar and normal solutions, reducing the likelihood of generating concentrated waste.
• Obtain access to an SDS for each chemical and consult the SDS before using a chemical.
• Read labels. Handling and storage information is on the manufacturer’s label.
• Purchase chemicals in plastic containers to minimize potential breakage. If this is not possible, purchase shatter-resistant plastic-coated bottles.
• Manage first in, first out! Indicate the date received and the date opened.
• Dispose of open, partially used or expired date chemicals.
• Peroxide-forming compounds require frequent safe-to-use testing or disposal.
• Keep all chemical containers off floors, carts and electrical equipment.
• Physically segregate chemicals according to compatibility.
• Label the secondary storage containers or areas whwere particularly hazardous chemicals may be used. These substances must be kept in a Designated Area.
• Store hazardous chemicals below eye level. This simple task reduces the likelihood of something falling from above and breaking.
• Cabinets with doors are safer locations than open shelves for hazardous chemicals.
• Safely transport any hazardous chemical. Place in secondary containment such as a bottle carrier.
• Avoid placing any chemical container in direct sunlight, underneath a sink or near heat sources.
• Place volatile or flammable chemicals only in specially designed refrigerators.
• DO NOT STORE HAZARDOUS CHEMICALS, FLAMMABLES, AND CRYOGENIC LIQUIDS IN COLD ROOMS.
• Be especially careful with reactive chemicals. Obtain and read the SDS for each reactive chemical you may have or work near.
• Label all containers in the laboratory with the following information (this includes any stock or working solutions):
  • Name of chemical or stock solution
  • Date Started
  • Your initials
  • Hazard warning (i.e., flammable, toxic, corrosive, reactive)
• Separate by hazard class. Do not store merely by alphabetical order.
• Use and manage your chemical fume hood, wisely. Too many chemical containers or equipment block the air slots and compromise the containment performance.
• Follow all waste disposal guidelines.

Storage of Flammable Liquids

• Limit the number of flammable liquids in use to the smallest practical volume. Work with flammable liquids inside a chemical fume hood. Return all flammable liquids to an approved flammable storage cabinet. The doors to flammable storage cabinets must close securely. Self-closing doors are best. Contact Research Safety for assistance in ordering flammable storage cabinets.
• The maximum quantity of flammable and combustible liquids that can be stored openly or within an approved flammable storage cabinet is defined for each campus. See the Laboratory Safety and Chemical Hygiene Plan.
• The purchase of 5-gallon (20-liter) containers of flammable liquids is strongly discouraged. All transfers of flammable liquids from containers of five gallons or more must be performed inside a fume hood. These containers also must be stored in a flammable storage cabinet.
• Segregate flammables from oxidizers and oxidizing acids.
• Most refrigerators/freezers purchased by the labs are designed for non-hazardous materials. Refrigerators and freezers suitable for flammable material storage are specially labeled “Explosion safe” of “Explosion proof.”

Storage of Gas Cylinders

• Generally, only keep cylinders in your lab that are currently used or waiting for immediate use.
• Large toxic gas cylinders must be in an approved gas cylinder cabinet.
• There are defined maximum allowable storage quantities for cylinders.

• All cylinders not attached to a regulator must have a valve protection cap.
• For vertical storage, cylinders must be secured (at a minimum) in their upper third by a tight-fitting chain or belt secured to the wall or non-movable casework. This applies to all cylinders.
• One cylinder per chain or web belt.
• Horizontal storage of cylinders is only allowed in racks designed for the purpose. Cylinders must be secured to the rack.
• Cylinders must not be kept in corridors, hallways, stairways, cold rooms, or any other area with limited ventilation.

Handling Cryogenic Fluids

• Cryogenic liquids, such as liquid nitrogen, must be handled only in containers designed for that purpose.
• Full face protection (face shield) including safety glasses and goggles as well as insulated gloves, lab coat, covered shoes must be worn when handling cryogenic liquids.
• When transferring liquid from one container to another, the receiving container must be cooled gradually.

Example of a labeled SAA:

Refer to the following list for specific disposal information:

Acids and Bases

1. Collect concentrated acids and bases in original containers whenever possible. This includes nitric, hydrofluoric, sulfuric, glacial acetic, hydrochloric, sodium hydroxide, and ammonium hydroxide. Hydrofluoric acid etches glass and must be collected in plastic containers. Be aware that some acids are incompatible (for example nitric acid and glacial acetic waste). Never mix oxidizing acids with organic chemicals.
2. Acids and bases may be treated as the last step of a reaction. Neutralized solutions may be disposed of down a lab sink with copious amounts of water provided they are treated as follows:

• Slowly stir acid in a large amount of an ice-water-to dilute to about 5% by volume.
• Prepare a base solution of one of the following: sodium carbonate (soda ash), or sodium hydroxide. The base concentration should be 5 to 10 % for nitric and perchloric acid neutralization. A one-molar solution is about 4% (4 grams per 100 ml).
• Slowly stir diluted acid into the base solution until the pH is at least 5 but not greater than 10⁴.
• Slowly pour the neutralized solution down the drain with large amounts of water.

     3. No solvent or metal contamination is permitted for drain disposal.

    NOTE: The use of chromic acid or Chromerge® is strongly discouraged. If used, these glass cleaning solutions must be collected through the third rinse.

Acrylamide

1. Dispose of unused/unwanted acrylamide powder or opened liquid as hazardous waste.
2. Collect acrylamide gels that contain ethidium bromide, in a lined five-gallon plastic pail.

NOTE: Only small amounts of liquid can be placed in a bag. For large amounts of unpolymerized acrylamide liquid use a container.

Aerosol Cans

If completely empty and punctured, aerosol cans may be disposed of as trash. If contents or pressure remains, dispose through Research Safety.

Aqua Regia

Aqua regia is typically a 3:1 mixture of Hydrochloric Acid (HCL) and Nitric Acid (HNO3). It is commonly used to remove metals and trace organic compounds from glassware, and noble metals from some substrates.

Aqua regia MUST be prepared in a fume hood.

PPE

Proper PPE must be worn while making or handling aqua regia. This includes a lab coat, face shield, safety glasses, neoprene apron and neoprene gloves.

Preparation and Handling

Aqua regia should be made fresh before use; it should never be stored. Aqua regia should only be prepared and handled in clearly labeled glass containers (preferably Pyrex) inside of a fume hood free and clear of other chemicals. When preparing aqua regia, always add nitric acid to the hydrochloric acid. The concentration of nitric acid must always be less than 38%.

Aqua regia is an oxidizer that will oxidize over time, forming toxic gases, such as nitrogen dioxide and chlorine. Therefore, aqua regia should be disposed of immediately after use. Aqua regia should never be handled outside of a fume hood. Never tightly cap an aqua regia container.. Aqua regia should only be handled with PTFE or glass implements. Aqua regia can corrode and react violently with metal.

Disposal

Allow aqua regia solution to cool in an open container, in a working fume hood, preferably overnight. Place a sign on the fume hood alerting people to the hazard. You should neutralize aqua regia before disposal, according to the procedure below. Once the aqua regia is neutralized, submit for disposal.

1. Place the neutralization container in a secondary container onto a stir plate inside a fume hood. The neutralization container must be glass, free of any organic residue, and large enough that the dilution water and aqua regia is no more than 2/3 of the total volume of the container. The amount of solution water needed is 7.5 times that of aqua regia.
2. Weigh out the necessary amount of magnesium hydroxide (0.53 grams per mL of aqua regia).
3. Add the total necessary volume of dilution water to the neutralization container and begin stirring with a PTFE coated stir bar without over-agitating the water.
4. Add the magnesium hydroxide and a dash of bromothymol blue solution to the beaker. The bromothymol solution is prepared with 0.8 g of bromothymol blue, 100 mL of water, and a drop of NaOH.
5. SLOWLY add the aqua regia to the full volume of water, carefully avoiding overheating. The bromothymol blue indicator will turn yellow if you overshoot neutral pH. If your solution turns yellow, but there is still undissolved magnesium hydroxide, let the solution stir longer to equilibrate. Test the pH using a pH strip and add more magnesium hydroxide if necessary.
6. Allow the solution to cool to room temperature before moving the container, capping the container, or transferring the solution.⁵

Once the solution has cooled, it may be transferred to another glass container for pickup. Use a pressure-venting cap. Label the waste bottle appropriately and submit a pickup request immediately. Avoid combining multiple batches of aqua regia solution into one waste container; Hazardous Waste Professionals will pick up multiple containers.

Arsenic

Liquid wastes⁶ containing more than 0.25mg/L  are regulated. List all arsenic-bearing compounds on the chemical waste label.

Asbestos

Wet asbestos-containing lab ware and bag them up for disposal.

Azides

See sodium azide.

Barium

Liquid wastes⁷ containing more than 2mg/L are regulated. List all barium-bearing compounds on the chemical waste label.

Benzene

Liquid waste⁸ containing more than 0.5mg/L are regulated.

Blood and Biological Waste (see Biological Waste)

Bromine Solution Waste

Bromine solutions containing more than 1% bromine must be collected in containers no larger than 1 gal. List all bromine-bearing compounds on the chemical waste label.

Cadmium

Liquid wastes⁹ containing more than 2mg/L are regulated. List all cadmium-bearing compounds on the chemical waste label.

Chemical Carcinogens and Mutagens

Discard in an original or closed container. Bag up associated contaminated disposable labware. Triple rinse empty containers and collect all rinsate as chemical waste.

Chloroform

Liquid wastes¹⁰ with concentrations of more than 6mg/L are regulated.

Chromium

Liquid wastes¹¹ with concentrations of more than 25mg/L are regulated.

Contaminated Glassware

Chemically contaminated glassware, pipette tips, needles, blades and sharps are collected in a puncture-proof container.

Broken glassware not contaminated with hazardous chemicals can be put in a cardboard container, sealed and picked up as trash.

Copper

Liquid wastes with concentrations of more than 3mg/L are regulated¹².

Cyanides

Cyanides, nitrites, and sulfides are a chemical lab's most toxic and rapidly acting substances. Symptoms of toxicity occur if these materials are swallowed, inhaled, or absorbed through the skin. Keep stored in locked and secure locations away from acidic materials. Always use secondary containers to help prevent breaks or spills. Wastes containing more than 5ppm (5mg/L) are regulated¹³.

Dioxane

Dioxane (1,4-Dioxane) is a highly flammable liquid and can form potentially explosive peroxides upon long exposure to air. Containers of dioxane must be dated when opened and tested periodically for the presence of peroxides. If old, undated dioxane is found, do not open it. Contact Research Safety immediately.

Drain Disposal

The range of substances that can be potentially hazardous is enormous. Almost any substance can be a hazardous waste if it is disposed of in large quantities or in high concentrations. Federal and state hazardous waste laws permit laboratories to dispose of small amounts of some chemicals in quantities that do not pose a hazard to human health or the environment. It is Northwestern University's policy to prohibit the drain disposal of all potentially hazardous chemicals and take a more conservative approach when confronted with a less defined disposal situation.

Suitable for Drain Disposal (See Appendix C)

NOT Suitable for Drain Disposal

1. Inherently toxic, malodorous, or lachrymatory chemicals
2. Solutions containing heavy metals
3. Flammable liquids (flash point < 140◦F) of any type
4. Organic solvents—methanol, acetone, hexane, chloroform
5. Paint and paint thinner
6. Poisons, carcinogens, teratogens or embryotoxic chemicals
7. Toxic dyes and stains
8. Sodium azide
9. Strong acids and bases (outside of pH 5-10)
10. Chromic/sulfuric acid cleaning solutions
11. Photographic fixer
12. Motor oil, gasoline, degreasing solutions, antifreeze or other automotive fluids
13. Pesticides

Drugs and Controlled Substances

See Pharmaceuticals

Ether

Ether is a highly flammable liquid and can form potentially explosive peroxides over time. Containers of ether must be dated when opened and tested periodically for the presence of peroxides. Ether cans have expiration dates on the label. Dispose before they expire. If old, undated ether is found, do not open. Contact Research Safety immediately.

Ethidium Bromide (ETBR) & Propidium Iodide

Dispose of ethidium bromide staining and running buffer solutions in a closed container. For the collection of acrylamide gels that contain ethidium bromide, dispose of in a lined five-gallon plastic pail.

Never use bleach to treat EtBr wastes. This increases toxicity.

NOTE: SYBR Safe® is sold as a safer alternative to Ethidium Bromide. It is less toxic and the stain and gels can be disposed as regular waste. SYBR Safe can be used in the same manner as the solutions of EtBr. Tests indicate that it is just as, if not more sensitive than EtBr. It can also be read similarly with a standard UV or visible light trans-illuminator, or laser-based scanner. SYBR Safe is provided ready to use as a concentrate, it can be cast directly in the gel or used as a post-stain. It may also be used to stain RNA in gels. Recommended storage time is six months at room temperature.

Filters, Used

Filters used with hazardous chemicals must be disposed of as chemical waste. Examples are charcoal canisters used to filter waste anesthetic gases and vacuum pump filters.

Formalin/Formaldehyde/Glutaraldehyde/Paraformaldehyde

1. Unwanted or unused formalin or formaldehyde must be disposed through Research Safety.
2. If you have many specimens preserved in formalin that you wish to dispose of, contact Research Safety to discuss disposal options.

NOTE: The use of so-called “cold sterilant” such as Cidex® or other higher molecular weight aldehydes such as glutaraldehyde is strongly discouraged for both occupational and environmental reasons.

Formamide

Formamide must be collected. If radioactive, attach a Radioactive Waste Label and dispose of as radioactive waste.

Gas Cylinders

Compressed gases are among the most problematic wastes to handle and dispose. Rent gas cylinders if possible so cylinders can be returned to the gas vendors if empty or not routinely used.

Lecture bottles can be a serious disposal problem. If possible, return these to the manufacturer or supplier for reuse. If not, dispose of it through Research Safety. Label integrity is essential. Ensure that the label on each cylinder is legible. Keep the valve protection cap on the cylinder when not in use. When the cylinder is in use, keep this valve cap near it, so it does not get misplaced. Return gas cylinders to Lab Gas Services.

NOTE: Never dispose of hazardous gases by releasing outdoors or in a fume hood.

Gloves, Papers, Cardboard

Bag up gloves, papers, or cardboard that are grossly contaminated or were immersed in hazardous chemicals.

Dispose of gloves, papers or cardboard not contaminated with hazardous chemicals, radioactive materials or potentially infectious agents as trash. See Appendix C.

Laboratory Equipment

Any scientific equipment must be carefully surveyed and decontaminated when it may have been in contact with potentially hazardous biological, chemical or radioactive materials.

Submit a completed Laboratory Equipment Disposal Form .

Lead

Solid wastes¹⁴ containing more than 5 ppm lead are regulated.
Liquid wastes containing more than 0.5 ppm (0.5 mg/L) lead are regulated¹⁵.

Malodorous Waste

Sometimes closed primary containers may not be sufficiently odor tight. Bag or put in secondary container malodorous containers such as thiols, mercaptans, phenol/chloroform and sulfides.

Mercury

Mercury and mercury compounds are especially hazardous. If spilled, elemental mercury in cracks of lab benches or floor tiles may pose an exposure hazard for years. Few hazardous waste facilities accept mercury. Therefore, it is essential that the use of mercury be avoided. Substitute mercury thermometers with non-mercury alternatives or electronic devices to measure temperature and pressure.

Solid wastes¹⁶ containing more than 0.2 ppm must be disposed through Research Safety.
Liquid waste containing more than 0.5 ppb (0.5micrograms/L) are regulated¹⁷. For mercury spill kits or spill response assistance, contact Research Safety. After a metallic mercury spill, the air quality clearance level is three micrograms per cubic meter¹⁸.

See also Fluorescent light bulbs for clean-up of broken bulbs containing mercury.

Naturally Occurring Radioactive Materials (NORM)

NORM refers to all radioactive elements found in the environment where human activities have increased the potential for exposure compared with an unaltered situation.

Chemical compounds containing NORM are mostly purchased as staining agents for electron microscopy. Common compounds contain long-lived radionuclides such as uranium and thorium. Typical commercial forms include samarium, uranium oxide, uranium fluoride, uranium nitrate, uranium acetate, thorium oxide, fluoride, and thorium nitrate acetate.

All chemical compounds containing NORM must be collected and disposed of as radioactive waste. Uranium nitrate and thorium nitrate are considered radioactive and oxidizers, and are treated as “mixed waste”.

Never mix aqueous uranyl acetate with other staining compounds such as lead citrate or heavy metals, solvents, and other hazardous chemicals.

All liquid and solid radioactive waste must be accumulated in properly labeled containers provided by Research Safety- Health Physics Services.

Nickel

Liquid waste containing more than 10 ppm (10mg/L) is regulated¹⁹.

Nitric Acid

Many reported laboratory waste container ruptures and explosions involve accidentally mixing nitric acid with reducing agents (e.g., organic compounds). Avoid creating nitric acid waste mixtures with acetone, acetic acid, acetic anhydride, alkali metals, cyanides, aldehydes, powdered metals organic materials, ammonia, acetonitrile, alcohols, acrylonitrile, and organic matter.

Nitric acid is a powerful oxidant. Violent and sometimes explosive reactions with liberation of toxic nitrogen oxides can happen after significant time delay. Oxidation is invariably accompanied by gas evolution, usually capable of rupturing closed vessels.

Oils

Uncontaminated instrument and machine oils such as centrifuge, diffusion, and vacuum pump oils must be collected in plastic containers and labeled with a Chemical Waste Label. Oils found in X-Ray machines and other devices may contain PCBs (polychlorinated biphenyls), especially if the equipment is old. DO NOT MIX PCB*CONTAMINATED OIL WITH OTHER OILS. Contact Research Safety if you suspect you have PCB oil.

NOTE: All vacuum pumps must be emptied of oil before disposal. If sending them out for service, they must be rinsed and purged with clean oil. Collect rinse oil for disposal through Research Safety.

Organic Mercury (Alkyl and Aryl) Compounds

Organic mercury compounds pose special hazards in the laboratory. Under all circumstances, these compounds must be handled according to the Laboratory Safety and Chemical Hygiene Plan. Alkyl mercury compounds require prior approval from Research Safety before purchase or use.

Osmium Tetroxide

Osmium tetroxide can be converted to a less volatile (safer) form by adding corn oil to the solution and shaking. This method takes advantage of the double bonds of the unsaturated oil to form a cyclic osmic ester. The reaction may be slow because corn oil is not readily miscible in water, but it’s easy and works.

Bag up osmium tetroxide contaminated labware or dispose of in a closed container.

Paint

Paint can be a significant potential source of pollution in landfills. Dispose of all oil-based paints through Research Safety. Old, unwanted full cans of latex paints must be disposed of through Research Safety. Opened, empty cans of latex paint can be allowed to air dry until solid then be disposed in the trash as non-hazardous waste. This must be waste generated at Northwestern University. You may not bring personal wastes from home for disposal through Northwestern University.

Paint Thinner, Related Chemicals, Contaminated Rags

Chemicals associated with the use of paint thinner, brush cleaners, linseed oil, etc. must be collected for disposal by Research Safety. Rags and paper towels contaminated with paint thinner or related chemicals are chemical waste. Contact Research Safety for more information on fire rated collection containers and disposal.

Perchloric acid reacts violently with many substances. The anhydrous (dehydrated) acid presents a serious explosion hazard. It is unstable and can decompose explosively at ordinary temperatures or in contact with many organic compounds. Amounts in labs must be limited to 500 grams or less. Any work with perchloric acid heated above ambient temperature requires Research Safety approval. Special wash-down hoods may be required.

Many heavy metal perchlorates and organic perchlorate salts are extremely sensitive explosives; the ammonium, alkali metal and alkali earth perchlorates are less hazardous. Mixtures of perchlorates with many oxidizable substances are explosive. Cold 70% perchloric acid is a strong acid but is not considered to be a strong oxidizing agent; however more concentrated solutions are good oxidizers. Work with >85% perchloric acid requires special precautions and should be carried out only by specially trained personnel and in specially designed fume hoods.

Peroxide Forming Compounds

Certain chemicals such as isopropyl ether, diethyl ether, dioxane, 2-butanol, and tetrahydrofuran can form organic peroxides. The organic peroxides become more concentrated if the solvents are exposed to air or evaporation. Organic peroxides may violently explode. (i.e., combined with metals or by heat, shock, friction, light or static discharge). Peroxide test strips are available through Research Safety. See the Laboratory Safety and Chemical Hygiene Plan for additional information.

Never move or open a container if crusty deposits form on the material or its container, an oily, viscous layer appears, or solids are on the bottom. Immediately contact Research Safety if rusted, damaged, undated, or suspicious-looking containers of peroxide forming materials are found.

• Clearly and explicitly label chemicals known to form peroxides.
• Always date the container when received and when opened.
• Limit the on-hand stock to a three (3) month supply or less.
• Air dry empty containers under the hood, flush them with water, deface the label and put containers in the glass disposal container.
• Store away from heat and light.
• Protect from ignition sources, physical damage, contact with strong reducing agents or oxidizers, or other contamination.
• Ensure air-tight closures on containers, and purge head space with nitrogen when possible.
• Keep a minimal working inventory.
• Never store in a freezer. Use explosion-proof or explosion-safe refrigerators, as needed.
• Never store in glass bottles with glass stoppers.
• Never attempt to clean containers that store peroxide-forming compounds by scraping or rubbing, especially if an oily deposit or crusty residue is present.
• Test for peroxide concentration before distilling or concentrating.
• Prevention of unwanted peroxides is paramount. Stabilization and disposal can cost up to $3,000 per container.

Pharmaceuticals

Controlled substances are only permitted with a valid Drug Enforcement Administration (DEA) license. Keep DEA-regulated drugs under lock and key security until the time of pick up. Any drugs provided by the Center for Comparative Medicine (CCM) must be disposed of through CCM.

Dispose otherwise acquired Schedule 2-5 DEA Controlled Substances through Research Safety. For other drug disposal requests send an email to hazardous-waste@northwestern.edu.

Phenol/Chloroform

1. Collect liquid mixtures. Indicate percentages on the label.
2. Phenol/Chloroform contaminated labware such as pipette tips and disposable pipettes with small volumes of liquid must be collected using puncture-resistant container. See also Small Vials.

Phenol/chloroform waste is malodorous. Bag up gloves, wipes and empty tubes.

It is not acceptable to throw this type of waste into general trash containers, autoclave in biohazard bags, or dispose of as biological waste.

Liquid wastes containing more than 0.3 mg/L phenol²⁰ are regulated.

Photographic Solutions

All darkrooms must be registered with Research Safety.

Used Fixer (Black & White, Color, Bleach, Microfilm, X-ray): Used fixer solutions are classified as a chemical waste and are prohibited from drain disposal.

Stabilizers and Activators: Some activators and stabilizers pick up unexposed silver during photo processing.

Indicator Stop Bath or Acetic Acid: If Indicator Stop Bath has changed color, the solution is neutral and can be disposed of down the drain. If the Stop Bath does not have an indicator, check the pH. Adjust the pH to between 5-10 before drain disposal. Collect Indicator Stop Bath or acetic acid solutions that do not meet these conditions as hazardous waste.

Developers – Black & White: These solutions can be disposed of down the drain. Identify the chemical constituents from the product’s SDS and call Research Safety for disposal information.

Developers – Color: Some color developers contain hazardous constituents and others have a pH that prohibits them from being disposed of down the drain. Identify the chemical constituents from the product’s SDS and call Research Safety for disposal information and assistance.

Hypo Clearing Agent: These solutions can be disposed of down the drain.

Mixtures: Certain photo processing operations do not allow fixer collection separate from other photo chemicals. These mixtures cannot be discharged to the drain.

NOTE: All automated film processors must be equipped with silver recovery systems. Conversion to digital imaging systems is strongly encouraged.

Piranha Etch Solution

There are two types of piranha etch: acid piranha and base piranha. Standard acid piranha is a 3:1 mixture of concentrated sulfuric acid (H2SO4) and hydrogen peroxide (H2O2).

This reaction is extremely exothermic when the peroxide is added to the acid. A standard base piranha solution is a 3:1 mixture of ammonium hydroxide (NH4OH) and hydrogen peroxide (H2O2). This mixture must be heated to 60C before the oxidizing reaction takes place.

PPE

Wear proper PPE while making or handling piranha etch. This includes a lab coat, a neoprene or nitrile apron, safety glasses, and heavy-duty neoprene gloves. Additionally, you should wear a face shield.

Preparation and Handling

Piranha solution should be made fresh before use; it should never be stored. Piranha should only be prepared and handled in clearly labeled glass containers (preferably Pyrex) inside of a fume hood free and clear of all chemicals (especially organic compounds). When preparing piranha, always add the peroxide to the acid. The solution can explode if the peroxide concentration is greater than 50% in a piranha etch.

Piranha is used to remove residues, not actual compounds. Failure to completely remove the compound itself could result in an explosion, especially with organic materials. If piranha is mixed with enough organic materials, it will generate large quantities of heat and gas. Piranha reacts violently with most plastics and should only be handled with glass or PTFE lab ware.

Disposal

Hot piranha solution should be allowed to cool in an open container, preferably overnight, in a working fume hood. A sign on the fume hood should alert people to the hazard. Once the solution is cool, it may be transferred to another glass container for pickup. This container must have a pressure-venting cap, as piranha will continue to off-gas. Label the waste bottle appropriately.

Avoid combining multiple batches of piranha solution into one waste container; Hazardous Waste Professionals will pick up multiple containers.

Reactives

Chemicals that are considered reactive can react violently with air, water or other substances and have the potential to explode. These chemicals include picric acid, sodium cyanide and sodium azide.

• Segregate oxidizers from flammable and combustible materials, organic material and reducing chemicals.
• Pyrophoric chemicals ignite spontaneously in contact with air. Store breakable glass bottles inside a plastic bottle carrier. Keep these chemicals in a glove box.
• Shock-sensitive and explosive materials (benzoyl peroxide) can spontaneously release large amounts of energy when struck, shaken, dropped, or agitated. Some chemicals become increasingly shock sensitive with age. Inspect these regularly for degradation and dispose of them promptly. Consult the Safety Data Sheet (SDS) before working with reactives.
• Never contaminate reactive chemicals with heavy metals or incompatibles.

Selenium

Liquid wastes²¹ containing more than 1mg/L are regulated.

Silver

Liquid wastes²² containing more than 0.1mg/L are regulated.

Small Vials

Small vials filled with compatible chemicals may be collected with lids in wide-mouth quart, gallon jars or 5 gallon buckets. Separate containers are required for the collection of mercury-containing liquids, reactive, oxidizing and acutely toxic liquids. Label the outside of the collection container with all chemical contents. Choose the container size according to expected waste volumes so the container can be filled and frequently picked up for disposal.

Sodium Azide

Sodium azide is commonly used in low concentrations as a microbicide to preserve samples. Avoid exposure to the pure material and purchase sodium azide solutions when possible. Take care not to contaminate pure sodium azide with metals or foreign materials as this can form explosive metal azides. Azide solutions can also form explosive metal azides in drainpipes. Collect solutions and pure material for disposal. A best practice is to make azide waste solutions basic >pH 10 before submittal.

Solvents

Separate aqueous, halogenated, and non-halogenated waste streams if possible. Halogenated solvents include methylene chloride and chloroform. Non-halogenated solvents include methanol, acetone, and xylene. List all chemical constituents and the pH on the waste label. This includes any metals. Do not add excess solids or debris. Please get in touch with Research Safety for more information on solvent recycling.

Preprinted Research Fuel Blends tags are available through Research Safety for the collection of non-halogenated solvent wastes.

Staining Solutions

Collect staining solutions such as Wright’s, eosin, iodine and methylene blue stains in a sealed container. List the solvent concentrations on the waste label (i.e., water, glacial acetic acid, methanol).

Universal Wastes

Universal waste is defined as a hazardous waste that is “universally generated.” It has a lower risk relative to other hazardous wastes. Types of universal wastes recognized in Illinois are batteries, fluorescent light bulbs, mercury-containing devices, used automotive antifreeze, certain pesticides and color cathode ray tubes. A pickup request must be made within 9 months of accumulation. See Appendix D.

You may not bring personal waste from home for disposal through Northwestern University.

Unknowns

Analysis and disposal of material for which the identity is unknown can be expensive, from $300 to $1500 or more per sample. If unknowns are found, consult with other workers who may have an idea as to the identity of the material. Even a general chemical classification (such as “aromatic sulfur compound”) can be helpful. A phone call to a colleague who has left will pay for itself several times over.

To prevent unknowns, remember to label all your containers regardless of size. Labeling of stock solutions is essential. All labels must include the commonly accepted name (NO CHEMICAL FORMULAS). Include any special warnings, and the date made. When scientists plan to leave the University, contact Research Safety to help clean out the laboratory so that unknowns can be avoided.

List unknown materials on the Hazardous Waste Pickup Request. Including the color and physical state of these materials on the form and any other information that may help in identification is helpful.

When unknowns are found in the laboratory, exercise caution as these materials may be old and unstable. If you suspect unknowns are reactive, call Research Safety prior to moving these materials.

Zinc

Liquid wastes²³ containing more than 15ppm (15mg/L) are regulated.

Only dilute solutions of non-toxic materials shall be disposed of in the sanitary sewer system. This includes most normal biological metabolites and nontoxic cellular constituents (proteins, nucleic acids, carbohydrates, soluble fats, precursors and catabolites, common sugars, amino acids, non-toxic common salts (NaCl, MgCl2, etc) and biological buffers with pH between 5-10. (Phosphate buffers, saline, Tris, etc.).

Note that acid or base solutions containing organic or inorganic impurities (e.g. base baths or acidic solutions used to clean glassware) must not be flushed down the drain even if neutralized. These solutions must be collected for chemical waste disposal.

Only non-hazardous laboratory chemicals may be placed into the ordinary refuse (garbage) for disposal. Non-hazardous materials in an aqueous solution may be poured down the drain except for  >2% slurries of sand-, earth-, gypsum-, cement or other insoluble material.

Table C

Materials that do not appear on these lists MUST be collected for disposal.

NOTE THAT LIQUID NITROGEN OR DRY ICE MUST NEVER BE PLACED IN THE SINKS, AS THEY CAN CRACK THE SINK AND CAUSE DAMAGE TO THE PLUMBING.

Northwestern University's non-laboratory areas utilize and generate various hazardous substances. Hazardous waste handling and disposal compliance in non-laboratory areas is managed by Envinronmental Health and Safety and includes departments such as: Art Practice & Theory shops, Athletics, Facilities, Library Preservation Lab, Residential Services and Wirtz Center shops.

For disposal questions, contact hazardous-waste@northwestern.edu.

Aerosol Cans

If empty and punctured, aerosol cans may be disposed of as non-hazardous trash. Full or partially empty containers must be collected as hazardous waste.

Batteries

Various batteries used: lead-acid (automotive), mercury, lithium-containing, ordinary household and rechargeable. Dispose of all battery types through hazardous-waste@northwestern.edu .

Battery recycling boxes are available through Research Safety.

Cleaners, Degreasers, Parts Washers

Consult with hazardous-waste@northwestern.edu to set up collection, disposal and service options. Dispose of all degreasers and parts washing fluids as hazardous waste.

Fluorescent Light Bulbs

Collect all fluorescent light bulbs, package bulbs in break-resistant packaging and bring to the designated satellite accumulation area.

Broken light bulbs: Gather coarse debris, package in a closed container and use a sticky roller to pick up fine debris.

Gas Cylinders

If possible, return compressed gases to the manufacturer or supplier for reuse. Ensure that the label on each cylinder is legible. Keep the valve protection cap on the cylinder when not in use.

Glycol

Dispose of all spent glycol in a closed container and bring it to the designated satellite accumulation area.

Oils

Place waste oil containers in secondary spill containment.

Paint

Dispose of all oil-based paints and unwanted full cans of latex through hazardous-waste@northwestern.edu. Opened, nearly empty cans of latex paint can be allowed to air dry until solid then be disposed in the trash.

Paint Thinners, Related Chemicals, Contaminated Rags

Rags and paper towels contaminated with paint thinner must be collected and stored in a flammable-rated container and brought to the designated satellite accumulation area.

Pesticides

Dispose of all pesticides through hazardous-waste@northwestern.edu.

Photographic Solutions

Used Fixer (Black & White, Color, Bleach, Microfilm): Dispose in a designated container with a Hazardous Waste Label.

Stabilizers and Activators: Dispose in a designated container with a Hazardous Waste Label.

Developers – Black & White, and Color: Dispose in a designated container with a Hazardous Waste Label.

Solvents

Aqueous, halogenated and non-halogenated waste streams should be separated if possible. Common solvents include acetone and methanol. Solvents must be collected in compatible and right-sized containers. Attach a Hazardous Waste Label to the container. List all chemical constituents and pH on the waste label.

Saw Dust

Collect sawdust in a designated sealed container. Deposit no other material inside these containers. Dispose of as trash when full.

1. 35 Illinois Administrative Code 722
2. 35 Illinois Administrative Code 722.314
3. The mixture rule at 40 CFR 261.3(a)(2)(iv) states that if you mix a solid waste with any listed waste, the entire mixture is listed hazardous waste. Discarded, unused, commercial chemical products arising from what are known as de minimis losses are exempt from the mixture rule when they are discharged through a wastewater treatment system regulated by the Clean Water Act.  De minimis losses include spills from unloading or transfer of materials, leaks from process equipment, leaks from well-maintained pump packings and seals, sample purgings, relief device discharges, safety shower discharges, rinsing and cleaning of personal safety equipment, and rinsate from emptying containers.
4. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
5. Adapted from University of Michigan Occupational Safety and Environmental Health Aqua Regia SOP
6. 2015 MWRD Sewage and Waste Control Ordinance, Appendix A Section 8"
7. 2015 MWRD Sewage and Waste Control Ordinance, Appendix A Section 8"
8. Source: 40 CFR §261.24
9. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
10. Source: 40 CFR §261.24
11. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
12. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
13. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
14. Source: 40 CFR §261.24
15. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1
16. Source: 40 CFR §261.24
17. 2015 MWRD Sewage and Waste Control Ordinance, Appendix A Section 8
18. EPA/ATSDR National Mercury Cleanup Policy Workgroup, 2012
19. Source: 40 CFR §261.24
20. 2015 MWRD Sewage and Waste Control Ordinance, Appendix A Section 8
21. Source: 40 CFR §261.24
22. 2015 MWRD Sewage and Waste Control Ordinance, Appendix A Section 8
23. 2015 MWRD Sewage and Waste Control Ordinance, Appendix B Section 1