A chemical hygiene officer (CHO) for a high school science department decided to inspect a chemistry laboratory, preparation room, and chemical storeroom after one of its chemistry teachers retired at the end of the school year in June. In one of the corrosive chemical cabinets in the chemical storeroom, a large undated bottle of picric acid (IUPAC name 2,4,6-trinitrophenol) was found with crystals growing around the metal cap. Picric acid is in the family of nitroaromatic explosives as trinitrotoluene (TNT) and can be used as a bio-stain for collagen fibers. It forms shock-sensitive explosive salts with metals (such as lead) and is too unwieldy for most usual applications.

The CHO remembered that several years ago, bomb squads were sent to several high schools in the Midwest to remove this potentially dangerous explosive. Concerned about the serious chemical hazard and health/safety risk the picric acid presented, the CHO contacted the local fire marshal and state bomb squad to safely and promptly have the bottle of picric acid removed from the school grounds.  

This scenario is unfortunately not uncommon. Biological and chemical waste is highly regulated by local, state, and federal laws and therefore must be disposed of in a safer way. The Occupational Safety and Health Administration (OSHA) designed specific components in the Occupational Exposure to Hazardous Chemicals in Laboratories Standard (the Laboratory Standard) 29 CFR 1910.1450, and the Hazard Communication Standard 29 CFR 1910.1200, to help prevent or reduce hazardous waste accidents by requiring the development and use of biological/chemical waste management programs. The Resource Conservation and Recovery Act (RCRA), enacted in 1976, is the federal law that requires all institutions to have guidelines to reduce the amount of hazardous materials, and in conjunction with the Environmental Protective Agency (EPA), to promote methods to protect human health and the environment.   

The picric acid should never have been stored because there could have been potentially disastrous consequences for employees and students. Whether these hazardous chemicals are expired, not used any longer, or just present an unacceptable potential hazard and risk—through shared responsibility of the administration, faculty, staff, and CHO—the hazardous materials must be removed and discarded using appropriate legal safety standards and better professional safety practices. 

This blog post aims to raise academic laboratory educators’ levels of awareness of general recommendations for developing biological/chemical waste management with an emphasis on disposing of potentially hazardous laboratory biologicals and chemicals. By EPA definition, biological/chemical waste management is the collection, treatment, and disposal of waste material that can cause harm to human health or the environment. 

The first activity that must be completed to prepare for hazardous waste management disposal is to determine what hazardous wastes are present and the manner of which they are to be disposed. The following is a recommended action plan for removal and disposal of hazardous waste.

1. Do a hazard analysis and risk assessment for any potential chemical waste (e.g., review Safety Data Sheet [SDS], labels, Environmental Health and Safety consult, etc.)
2. Determine appropriate safety actions to follow based on the hazard analysis and risk assessment performed; e.g., personal protective equipment (PPE) to be worn, etc.
3. Choose a location to store the hazardous waste before beginning the process.
4. If there are potentially hazardous/dangerous biological or chemical waste findings, immediately contact the safety compliance officer and/or CHO. Do not touch the biologicals or chemicals! Also contact the chief building administrator and supervisor.
5. Contact the facilities director or other school employee who will be responsible for finding a biological/chemical waste commercial company to remove the appropriate waste products.
6. Do an annual biological and chemical waste disposal clean out of the instructional spaces and related space sites.

Generally, biological and/or chemical hazard disposal protocol requirements include the following.

• Proper storage. Make sure waste chemicals are compatible and stored on a stable space with less frequent foot traffic.
• Proper labeling. Labels need to be securely placed on bottles/containers based on current OSHA Hazard Communication Standard labeling requirements, including full biological/chemical name, physical state, and generator identifier, at least one signal word, hazard statement(s), precautionary statement(s) and pictogram(s).
• Pre-planning. Know what waste is being created before carrying out laboratory experiments and demonstrations so that purchases and storage can be minimized or appropriate disposal containers can be obtained.
• Recordkeeping. Have inventory records of all waste biologicals/chemicals on hand and those already picked up for disposal.

Do not combine incompatible or unknown chemicals in one container. By combining two or more incompatible or unknown types of biologicals or chemical materials, toxic vapors can develop, or a dangerous reaction such as a fire or explosion can happen. The Chemical Hygiene Plan and/or Hazard Communication Plan should include a policy in which no biologicals or chemicals are to be combined when in use or when preparing them for disposal. Liquid waste should also be secured in leakproof containers. Check the SDS for any other storage rules, such as ventilation requirements or the maximum level storage containers should be filled to allow for vapor expansion.

OSHA requires that chemical manufacturers provide SDSs for every hazardous chemical. SDSs, formerly known as Material Safety Data Sheets, are standardized documents that contain health and safety data about specific chemicals. They typically contain information such as

• the properties of the chemical;
• any associated health and environmental hazards;
• protective measures lab technicians should take when handling the chemicals;
• any other safety precautions that should be taken for storing and transporting the chemicals; and
• recommended disposal measures.

Once biological and/or chemical waste is found, ensure it is properly identified. All waste containers must include labels that identify the waste. Never use abbreviations; spell out the name of the substance completely.

Appropriate storage and disposal matters for these reasons. 

1. Storm drains discharge directly into local lakes, streams, and rivers.
2. Wastewater treatment plants are not designed to remove biologicals/chemicals.

• Laboratory chemical and biological products can pass through the treatment process and into the environment.
• Certain chemicals can upset the wastewater treatment process and result in raw sewage dumping into the environment.

3. Landfills can leak organic liquids and heavy metals into groundwater.

4. Worksite chemical hazards/risks can result in employee injuries.

Many potential types of biological and chemical hazardous waste are commonly found in academic instructional sites (laboratories and classrooms) and related locations (chemical storerooms and preparation rooms). Referencing the SDS section 11 will classify the toxicological information. Included are examples of the more common potential hazards.

• Flammable liquids, flash point <60 C/140 F

         (Aqueous alcohol solutions <24% ABV* exempt)

• Oxidizers and peroxides
• Flammable solids (e.g., metal powders) and explosives
• Halogenated organic solvents
• Corrosive liquids and solids (pH less than or equal to 2 or greater than or equal to 12.5)
• Pyrophoric and water-reactive materials
• Compressed gasses (all)
• Heavy metals (Ag, As, Cd, Cr, Hg, Pb, Se)
• Toxicity

–    Oral rat LD:50 <5,000 mg/kg
–    Fish LC:50 < 10 mg/L
–    Inhalation rat LC:50 <200 mg/L
–    Dermal rabbit LD:50 <20,000 mg/kg 
*ABV = Alcohol by volume; LD = Lethal Dose; LC = Lethal Concentration

In addition, some household products commonly used also may be hazardous, including but not limited to these.

• Antiseptics and disinfectants
• Herbicides, fungicides, rodenticides, and insecticides
• Dyes, pigments, glazes, inks, thinners, and paints
• Etching solutions
• Commercial cleaners and metal polishing compounds
• Pyrotechnics, including road flares
• Drain and oven cleaners

In addition, recycling and other special wastes may be found in science, technology education/engineering, Career and Technical Education (CTE), and STEM labs, including these.

• Used oil and antifreeze 
• Paint, varnish, and paint-related materials (e.g., paint thinner and stripper)
• Adhesives
• Used alkaline and lithium-ion batteries
• Depleted fluorescent, ultraviolet (UV), and metal halide lamps
• Mercury-containing instruments
• Organisms and/or microorganisms—Deactivated and/or sterilized (by autoclaving) before discarding
• Broken glass and sharps—Disposed in appropriate containers
• Human body fluids, body fluid–contaminated items, and tissues
• Contaminated media products or Petri dishes
• Animal specimens, carcasses, and tissue washed and/or dried from preservative solutions
• Dry sharp objects placed in a sharps container

The following list will help you prepare for a safer waste disposal activity (Section 13 of the SDS).

1. Identify appropriate disposal storage site(s).

–    Safe from damage
–    Doesn’t impede work
–    Readily and unimpeded access
–    Secure when instructional or related space is unattended

2. Waste Containers

–    Impervious to intended contents
–    Tight-fitting cap/lid
–    Undamaged
–    Labeled upon first addition of waste
–    Clean exterior
–    Kept in a secondary waste container in case of accidental leakage

3.    Waste Compatibility 
–    Combine only wastes that are compatible with other constituents.
–    Leave at least one inch of headspace in containers.
–    Do not place solid objects in narrow-mouthed vessels.
–    Do not place wastes that may cause overpressure in tightly sealed containers.
–    Do not combine mercury-bearing wastes with any other waste.

4.    Removing Waste From Instructional Space/Related Work Areas

• A dangerous hazardous waste is a biological or chemical material with properties that make it capable of having a harmful effect on human health or the environment. 
• Dangerous waste must be removed as soon as possible once the container is filled, unless it poses an immediate danger.
• Consult your safety compliance officer and/or CHO for instructions.

The type of potentially hazardous biological or chemical waste found will determine how and when the waste can be disposed. Flinn Scientific has great resources on biological and chemical disposal procedures. Some examples include the following.

1.    General trash

• The following materials can be discarded in the trash providing there are no free-flowing liquids or items contaminated with Ag, As, Ba, Cd, Cr, Hg, or Se.

–  Sugars, agars, gums, amino acids, and inert solids such as talc, and dry resins and filter media
–  Dry wipes, bench papers and mats, empty containers, unbroken glassware, pipette tips, and weighing papers and dry resins and filter media

2.    Drain disposal

• You may dispose of the following aqueous solutions in the sink after the metal solid is precipitated or reclaimed: Ag, As, Ba, Cd, Cr, Cu, Hg, Se, or Zn. In addition, first check with your safety compliance officer and/or CHO to determine if your waste system can accommodate these via drain use (e.g., septic system).

–  Aqueous solutions containing buffers and salts (less than 10% by weight)
–  Neutralized inorganic acids and bases (pH 5–9)
–  Flowable aqueous gels, nutrient broths and agars
–  Spent formalin solutions
–  Used neutral pH cleaning solutions and “dishwater” from glassware cleaning
–  Some specimen preservation solutions not including formaldehyde.
–  The following inorganic salt cations have low levels of toxicity: Al, Bi, Ca, Fe, Li, Mg, K, Sc, and Na.
–  The following inorganic salt anions have low levels of toxicity: halides, carbonates, hydroxides, sulfates, and phosphates.

As part of a biological/chemical waste management program, an annual hazardous waste disposal should be required in instances when a dangerous waste is located. In that case, it is critical to have it removed immediately to help prevent a potentially serious safety incident, including harm to employees, students, and the facility. When in doubt, contact your school’s department of environment health and safety and/or CHO or district representative. Equally important and a legal requirement/better professional safety practice is the ongoing training of all employees annually dealing with instructional site biological and chemical use, storage, and disposal.

Safety Blog Acknowledgement

NSTA Chief Safety Blogger Dr. Ken Roy wishes to sincerely thank Brian C. Duffy, Ph.D., a nationally recognized Wayne Community College (Goldsboro, North Carolina) chemistry instructor, NSTA Research in Science Education Committee member, and former NSTA Safety Advisory Board Chair, for his professional review of this commentary.

Submit questions regarding safety to Ken Roy at safersci@gmail.com. Follow Ken Roy on Twitter: @drroysafersci.