SOP Example - Acutely Toxic Chemicals

This standard operating procedure (SOP) template is intended to provide guidance on working safely with acutely toxic chemicals. If you have questions concerning the applicability of any aspect of this SOP, contact your Principal Investigator (PI), Laboratory Supervisor, or the Environmental Health and Safety office.

This example cannot be used without customization. It is the responsibility of the Principal Investigator (PI) and/or Laboratory Supervisor to ensure that their SOP reflects their unique lab-specific and procedure-specific information.


1. Acute Toxicity

Acute toxicity is the ability of a chemical to cause an adverse or lethal effect after a single exposure. The Globally Harmonized System (GHS) uses LD₅₀ and LC₅₀ values to classify acutely toxic compounds:

  • LD₅₀: The amount of a chemical that when ingested, injected, or applied to the skin of test animals under controlled laboratory conditions, will kill one-half (50%) of the animals. Typically expressed as milligrams of chemical per kilogram of animal bodyweight (“mg/kg”)
  • LC₅₀: The concentration of the chemical in air that will kill 50% of the test animals exposed to it. Can be expressed in a variety of concentration units, including parts per million (ppm) and milligrams of chemical per liter of air (“mg/L”)

GHS defines four categories of acute toxicity (1-4), with Category 1 containing the most potent toxins. In general practice, a chemical is considered highly acutely toxic if it is in either Category 1 or 2. This corresponds to the following LD₅₀ /LC₅₀ values:

  • Oral exposure (ingestion): LD₅₀ ≤ 50 mg/kg
  • Dermal exposure (skin contact): LD₅₀ ≤ 200 mg/kg
  • Inhalation exposure: LC₅₀ ≤ 500 ppm (gases), 1 mg/L (vapors), or 0.5 mg/L (dusts or mists )

Highly acutely toxic chemicals are considered particularly hazardous substances (PHS) by Cal/OSHA, and they must be used only in designated areas. At USF, all laboratory spaces are considered designated areas for PHS use.

GHS Safety Data Sheets (SDSs) use numbered hazard statements to communicate hazards, although the numbers may not always be present. The presence of the following hazard codes or hazard statements indicate that a chemical is acutely toxic or highly acutely toxic:

Different hazard codes for acutely toxic and highly acutely toxic chemicals.
Acutely Toxic Highly Acutely Toxic
H302: Harmful if swallowed. H300: Fatal if swallowed.
H303: May be harmful if swallowed. H301: Toxic if swallowed.
H312: Harmful in contact with skin H310: Fatal in contact with skin.
H313: May be harmful in contact with skin H311: Toxic in contact with skin.
H332: Harmful if inhaled. H330: Fatal if inhaled.
H333: May be harmful if inhaled. H331: Toxic if inhaled.

2. Required Training

Before beginning work with acutely toxic chemicals, all personnel must have completed the following:

  • Laboratory Safety for Researchers.
  • Read the relevant Safety Data Sheets (SDSs).
    • Available from the manufacturer or from EH&S.
  • Complete any laboratory-specific training necessary to perform the procedures listed in this SOP.
  • Read and sign this SOP.
    • Any paper-based training records must be maintained in the lab.

3. Engineering Controls

  • Use a properly functioning chemical fume hood or other containment device when handling acutely toxic chemicals in a way that may generate aerosols, dusts, or vapors.
  • Weigh out acutely toxic solids in ventilated containment.
    • If containment for the balance is not available, dispense solids into a pre-weighed container in the fume hood. Close the container and transport to the balance for weighing, and transport the container back to the fume hood for additional dispensing if necessary.
  • If vacuum lines or pumps are utilized, use vacuum filters, cold traps, or other appropriate control measures to prevent contamination of the vacuum systems.

4. Administrative Controls


  • When possible, look for alternative procedures or reagents that will eliminate the need for the acutely toxic chemical, or substitute it for a less toxic chemical.
  • Never work alone. At least one other person familiar with the hazards of the acutely toxic chemical must be present in the laboratory.
  • Work with these chemicals must be performed in an area that is within 10 seconds (~ 55 feet) of a functioning safety shower and emergency eyewash.
  • Verify and review your experimental setup and procedure before beginning work.
  • Ensure all equipment is functioning properly.
  • Inform your colleagues about the acutely toxic chemical and where it will be used.
  • Use the smallest necessary amount of the acutely toxic chemical.
  • Consult with your PI or other knowledgeable person before scaling up procedures involving acutely toxic chemicals

5. Personal Protective Equipment (PPE)

Follow the PPE recommendations provided by your supervisor/PI and EH&S. This should include, at minimum:

  • Appropriate street clothing (pants and closed-toe shoes that cover the entire foot)
  • Lab coat
  • Safety glasses (or chemical goggles & face shield if a splash hazard exists)
  • Gloves of the appropriate chemical resistance

Additional PPE may be required depending on the specific operations contained within this SOP.


6. Handling and Storage

  • To minimize exposure to dusts or powders, handle solid acutely toxic chemicals in solution whenever possible.
  • Wash hands thoroughly after handling acutely toxic chemicals.
  • After the procedure, wipe down work areas and equipment with an appropriate cleaning agent.
  • Store all acutely toxic chemicals in chemically compatible secondary containers, and separate from any incompatible chemicals.

7. Waste Disposal

Waste materials generated must be disposed of as hazardous waste.

8. Incident Response/Medical Emergencies

Health-threatening Emergencies

  1. Call 911 for assistance.
  2. Go to the closest emergency room. Bring a copy of the SDS for the chemical.
  3. Notify your PI/supervisor and USF per the Employee Incident Protocol.
  4. Notify EH&S as soon as possible, but within 8 hours of the incident.

Non-health-threatening Incidents

1. Notify your PI/supervisor and USF per the Employee Incident Protocol.


Additional Instructions

The additional instructions below are to be followed for different types of chemical exposure.

Skin contact

Rinse body thoroughly using a safety shower for at least 15 minutes. If feasible, remove any contaminated or potentially contaminated clothing and/or jewelry.

Eye Contact

Rinse eyes thoroughly using an eyewash station for at least 15 minutes, occasionally lifting up the upper and lower eyelids to allow rinsing of the area beneath the eyelids. Remove contact lenses if possible.

Ingestion of chemical

Do NOT induce vomiting unless directed otherwise by the SDS or by Poison Control. Rinse mouth with water.

Inhalation of chemical

Move into fresh air.

Needle Stick/Puncture Exposure

Wash the affected area with soap and water for 15 minutes. Contact Poison Control.


If a small fire occurs, you are trained in the use of fire extinguishers, and you feel safe doing so, use a fire extinguisher to put out the fire. If a single extinguisher cannot put out the fire, activate a fire alarm and evacuate the area. Wait for emergency responders to arrive so that you can provide information about the fire.


9. Spill Response

  • Assess the extent of the spill and the hazards. DO NOT enter the area if you cannot assess the

conditions of the environment well enough to be sure of your own safety.

  • Evacuate the spill area. Avoid breathing vapors, dusts, or aerosols from spill.
  • If safe to do so, help contaminated or injured persons evacuate.
  • If possible, confine the spill to a small area using a spill kit or absorbent material. Keep others from entering the contaminated area (e.g., use caution tape, barriers, etc.).

Minor Spills

If the amount and type of chemical spilled presents no potential for hazardous chemical exposure and if you are trained to do so, wear appropriate PPE and clean up the spill. Double-bag any contaminated cleaning materials and manage as hazardous chemical waste. If you are not trained and/or there is a risk of chemical exposure, report the spill to your supervisor/PI.

Major Spills

Defined as any hazardous chemical spill that:

  • would result in chemical exposure during cleanup,
  • due to its size and/or hazards, requires capabilities beyond your training, or
  • results in a release into the environment (e.g. a spill goes down a drain).

Call 911 for assistance.

10. Operating Procedure

All sections must be completely filled out prior to use.

Procedure name Work with acutely toxic chemicals
Work location  
Approved Scale  
Date created/revised  
Emergency contacts  


Safety Equipment Identify the nearest eye wash, safety shower, fire extinguisher, fire alarm pull station, first aid kit (if available), and spill kit. Ensure that the fume hood or other ventilation control is functioning properly, and check the sticker to ensure that it has been certified within the last year
Procedure Setup  



General procedure
for acutely toxic
Weigh out solid acutely toxic materials in a fume hood. If a balance is not present in the fume hood, transfer the material to a tared vial, close the vial, and transport to the balance for measurement. If adjustment of the amount is needed, transport the closed vial back to the fume hood to do so. This will minimize exposure to any airborne dusts created by handling the solid. Subsequent activities involving the measured solids (such as dissolving in a solution) must also occur in a fume hood.
General procedure
for acutely toxic
Preparation of 4%
formaldehyde in PBS
from PFA powder


Waste Disposal Unused or unneeded acutely toxic chemicals must be disposed of as
hazardous waste. Ensure they are in a securely closed container labeled clearly as waste.
Any contaminated waste materials (weigh boats, disposable spatulas, paper towels, rinses from cleaning contaminated equipment, etc.) must also be disposed of as hazardous waste.
Clean Equipment and
Work Area

SOP Approval and Signatures

PI must ensure that all prerequisites (such as availability of PPE and engineering controls, safety training [including lab-specific training], and SOP signatures) are met before beginning work.

Personnel Trained on SOP

Name Signature DATE