Analytical Chemistry Trinidad & 

Tobago Lab Resources

Waste disposal in the chemistry laboratory

Handling hazardous laboratory waste. Proper labelling and storage of waste.
Accumulation, incompatibility and segregation of organics, acids, bases, and flammables.
OSHA compliance.

HOME Email Webmaster

Related links :
Disposal of peroxides
Aflatoxin waste disposal
Mercury spills
Disposal of spent drying media
Safety in the chemistry laboratory

Chemical Laboratory Waste Management and Disposai

This page gives info on the categorization, segregation and storage of labotatory waste prior to disposal. Laboratory personnel put all waste into a secured storage area where it is picked up for disposal by specially designated transport. Info on chemical disposal methods can be found in References 1, 2, and 3, at the end of this page. Refer to TT OSHA Act 2004 of which a synopsis is given below.

The Labeling of Waste

All bottles of chemical waste must have Label with date and contents.

Label all waste bottles.
If the contents of the bottle are not knomn, the next person to use the bottle could accidentally combine incompatible chemicals causing a fire and explosion.
Store waste in a bottle with the words "Hazardous Waste".
Labels such as "Organic Waste", "Xylene Waste" etc. are not rcommended. Label these as "Used Xylene" etc. which can be redistilled or put to other uses.
Do not scratch out the label on the bottle and write "Waste" on it. Remove or totally deface the old label so there is no confusion over the contents.

Storage of Waste

Do not store waste in a fume hood where reactions are being carried out.
If reaction gets out of control, the waste bottle could explode and lead to a fire or mixing of incompatible chemicals. Remove waste bottles from hoods where reactions are being carried out.
Do not use metal cans for waste.
Even near neutral pH, solids and liquids can corrode through metal cans. Use only glass or polyethylene containers for waste.
Do not store flammable waste containers on a bench or floor. Store waste containers in an explosion-resistant solvent cabinet.
Do not store waste bottles in a sink or floor drain.
Toxic chemicals can enter the sewer, and emit toxic gas causing health hazard or explosion.

Waste Bottles

Organic waste bottles must be capped.
However, to avoid a pressure buildup in the bottle, cap it loosely.
Do not leave funnel in the waste bottle.
A funnel can swing to an adjacent and incompatible waste bottle and cause a fire or explosion. After putting waste in bottle, cap it.

Accumulation of laboratory Waste

Try to have only ONE bottle of each kind of waste in the laboratory. If the organic waste bottle is full, take it to the waste storage area. Keeping many bottles of organic waste in lab poses a more serious hazard if a fire should occur.

Separating the Waste

Do not store acids and bases in the same cabinet.
Leaking containers or a spill could cause a violent reaction and emit toxic gases.
Do not store acids and organic waste in the same cabinet.
Perchance these chemicals should mix will result in fire and explosion.
Do not mix incompatible solvents in a waste container.
For example, nitric acid and ethanol can form an explosive mixture.

Proper separation of laboratory waste is mandatory for a safe workplace environment. Do not put all wastes in the same cabinet or fume hood. This can have disastrous results.
Make sure that any chemicals or wastes stored together are compatible with each other.
Only chemically compatible waste can be mixed together and placed in a common container for disposal.

Waste categoryExamples of compatibility
Can put in the same waste container bottle for disposal
Flammable solventsacetone, methanol, ethanol, toluene, xylene, acetonitrile, benzene etc..
(can all be put in the same disposal container)
Halogenated solventshalothane, methylene chloride, chloroform, carbon tetrachloride, trichloroethane, trichloroethylene
(can all be put in the same disposal container)
Organic acidsformic acid, acetic acid, propionic acid
(can all be put in the same disposal container)
Waste categoryExamples of Incompatibility
Cannot put in the same container bottle for disposal
Heavy metal solutionsaqueous solutions containing arsenic, barium, cadmium, chromium, copper, lead, mercury, osmium, selenium, silver etc..
(do not mix together, keep each type separate)
Mineral acidshydrochloric acid, nitric acid, sulphuric acid, perchloric acid
(do not mix together, keep each type of acid in separate container)
Inorganic Basessodium hydroxide, potassium hydroxide, ammonia
(do not mix together, keep each type in separate container)
Oxidizerspotassium nitrate, hydrogen peroxide,potassium permanganate, bleach
(do not mix together, keep all in separate containers)
Reactive wastesphosphorus pentoxide, sodium hydride, sodium methoxide, dry picric acid,
(do not mix together, keep all in separate containers)

For a list of incompatible chemicals click

NEVER store the following types of wastes near each other:

Acids and bases.
Organics and acids.
Cyanide, sulfide or arsenic compounds and acids.
Alkali or alkali earth metals, alkyllithiums etc. and aqueous waste.
Powdered or reactive metals and combustible materials.
Mercury or silver and ammonium containing compounds.
If a bottle broke in a waste storage area where incompatibles were present, the results could be disastrous. Remember: incompatible bottles of wastes should be stored in separate cabinets, preferably as far apart as possible.

Taking Waste to the Waste Storage Area

ALL waste containers MUST have a proper "HAZARDOUS WASTE" label with start date.

ALL contents are listed
The bottle or jar has a cap that fits tightly. If liquid, there is at least 1 inch of room at the top of the container.
The outside of the bottle is clean and dry.
Incompatible wastes are not mixed.
Halogenated wastes are separate from "regular" organic wastes whenever possible.
The pH is known and listed on the disposal tag.

Put label with waste information (this includes pH for ANY waste liquid, including organics).
Write out chemical names. No abbreviations and no chemical formulas (i.e. "Ether" instead of "Et2O" and "Dimethylphosphinoethane" instead of "DMPE").
Give the approximate percentage of each waste component.

The Trinidad and Tobago OSHA Act #1 of 2004

A Bill to deal with Industry Health and Safety with relevance to International Safety standards : the US OSHA and NEBOSH standards. The three main categories are :
  1. Worker Injury
  2. Fatal Accident
  3. OSHA Violation
It covers Risk Management, Worker rights and responsibilities, Refusal to work, Trade unions, Industrial conflict, Shutdown, Accident, Injury and/or death.
It authorizes OSHA Inspectors, Other inspection bodies, Compliance auditing and Liability control.
The impact of this bill is that it requires the employer to ensure a safe workplace, where hazards are controlled, and injury to worker is minimized.
The Trinidad and Tobago OSHA Act 2004 is now in effect. It's mandate is to regulate and set safety standards for all workplaces in Trinadad and Tobago.


Accidents that can cause death or serious injury must be reported to the Chief Inspector within 48 hours of the accident.
An accident in which the employee is disabled and unable to perform his normal duties should be reported within 4 days.
Failure to report these accidents to the Chief Inspector is to commit a safety and health offence and is liable to a fine of $20,000.00.
Empoloyees can annonymously make safety and health complaints to the agency at:
623-6742; 623-1462; Fax: 624-6591; email;

For info on Disposal Methods, Refer to the following:

1. "Waste Disposal in Academic Institutions", Kaufman J. A. (Ed), Lewis Publishers, Chelsea MI (1990).
2. "Immobilizing liquid Organic Laboratory Waste", Amos Turk et al, J. Chem. Ed. (1992) Vol. 69 No. 11
3. "Hazardous-Waste Disposal", Chemical reaction, Incineration and Landfill,[3].html

Signature: Dhanlal De Lloyd, Chem. Dept, The University of The West Indies, St. Augustine campus
The Republic of Trinidad and Tobago.
Copyright: delloyd2000© All rights reserved.