Unambiguous identification of chemicals in a laboratory is of utmost importance. Nothing is more difficult to handle than an unknown substance posing unidentified hazards. Disposal of unknown chemicals is expensive and requires a screening procedure to identify potential hazards. Laboratories are used by several people, and staff and students change frequently, so everyone who works in a laboratory is responsible for ensuring that chemicals and their associated hazards can be identified throughout their lifetime. 

Original Commercial Containers

The OSHA HazCom Standard 1910.1200 as it applies to laboratories requires that labels on incoming containers of hazardous chemicals must not be removed or defaced until the container is empty and rinsed. No chemical shall be accepted without an adequate identifying label. Original containers should be labeled with the date received and the date opened. This is particularly important for peroxide-forming compounds and other chemicals that become unstable over time, and it is good laboratory practice for ALL chemicals. 

Secondary Containers

If chemicals are removed from their original container and placed in a different container, this container is referred to as secondary container. The secondary container may hold the original chemical, a mixture of chemicals, or a dilution of a chemical in water or solvent. Secondary containers must be labeled with:

  • Full name(s) of the chemical(s). Do not use abbreviations as these can be ambiguous;
  • Hazard identification such as flammable, toxic, corrosive;
  • Date of transfer or preparation;
  • Name of person who transferred or prepared the solution;
  • If the container holds a solution or mixture, concentrations and solvents used (e.g., 1M hydrochloric acid; 40% acetonitrile / 60% water; 1 mg/ml naphthalene in hexane).

Make sure the label remains legible. Use a permanent marker that does not dissolve in water or the solvent used, or attach an adhesive label with the required information. For long term storage, check the label periodically (every six months) and replace it if it has become illegible. Containers stored in refrigerators are particularly likely to lose their labels. Check them more frequently or put them into a second container with an additional label inside. 

Very small containers such as vials can be labeled with a number or other code as long as they are accompanied by a sheet that lists the required information.

Temporary and Transfer Containers

Containers into which chemicals are filled only for the duration of the experiment, such as beakers, flasks, or test tubes, are referred to as temporary or transfer containers. At a minimum, they should be labeled with the name of the chemical. Common abbreviations whose meaning is clear to EVERYBODY in the lab such as ACN in a chromatography lab, or PBS buffer in a biology lab, are acceptable. If an experiment continues overnight or for multiple days, the label should also contain the name of the user.

Containers holding non-hazardous substances such as water must also be labeled to avoid confusion with other clear and colorless chemicals. 

Synthesized Compounds

All newly synthesized compounds should be labeled with the notebook number and page where a description of the synthesis can be found. If no name exists, draw the structure onto the label instead of a name. If the identity is not fully known, list the reactants, the expected structure, or the expected chemical class of the product (e.g., ester, aliphatic alcohol, aromatic amine). List your name, tared container weight, and synthesis date. If the product is expected to be hazardous, list potential hazards (e.g., may be explosive, toxic). 

According to the OSHA Laboratory Standard (1910.1450), the Hazard Communication Standard (OSHA 1910.1200) applies for a newly synthesized compound produced for a user outside the laboratory. This means that a safety data sheet has to be prepared, and the chemical has to be labeled with its name, appropriate hazard identification, and manufacturer’s name, address, and phone number. 


NRC (National Research Council). Prudent Practices in the Laboratory. Handling and Management of Chemical Hazards. National Academy Press, Washington, DC, 2011.

OSHA HazCom Standard 1910.1200

OSHA Laboratory Standard 1910.1450

Last Updated: 10/8/2019