7. ACUTE BIOLOGICAL TOXINS

Biological toxins are produced by certain bacteria, fungi, protozoa, plants, reptiles, amphibians, fish, echinoderma (spiny urchins and starfish), mollusks, and insects.

The following table lists the LD⁵⁰ values for commonly used biological toxins:

References:

1. Gill, Michael; 1982; Bacterial toxins: a table of lethal amounts; Microbiological Reviews; 46: 86-94
2. Stirpe, ; Luigi Barbieri; Maria Giulia Battelli, Marco Soria and Douglas A. Lappi; 1992; Ribosome-inactivating proteins from plants: present status and future prospects; Biotechnology; 10: 405-412.
3. Registry of toxic effects of chemical substances (RTECS): comprehensive guide to the 1997. Doris V. Sweet, ed., U.S. Dept of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio.

Some biological toxins are classified by the CDC and USDA as Select Agents (http://www.selectagents.gov/index.html or https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/animal-and-animal-product-import-information/sa_ag_select_agent ) due to their potential to pose a severe threat to public health and safety. Possession, use, and transfer of these toxins are highly regulated. A complete list can be found at http://www.selectagents.gov/SelectAgentsandToxinsList.html.

In small quantities, some of these toxins are exempt from select agent registration. See the table below.   Exempt Amounts of Select Agent Toxins Permissible Per Principal Investigator.

Because they can be extremely hazardous, even in minute quantities, biological toxins require strict safeguards against their inhalation, absorption through skin or mucous membranes (typically due to a splash), ingestion, or percutaneous injury. A chemical hygiene plan and MSDS specific for the toxin must be on hand in the laboratory for inspection.

Key points of the guidelines are:

1. Written safety protocols to cover the use of the specific toxin(s) in use;
2. Security measures in place to protect against unauthorized access to toxin(s);
3. Inventory control system in place; all entries in a hardbound book, in ink;
4. Written plan for toxin-related emergencies (spill, exposure, ) posted; and
5. BSL-2 or BSL-3 containment and practices.

Specific inactivation and disposal requirements should be in place for acute biological toxins. Some toxins are quite resistant to conventional methods of inactivation. These agents cannot be simply placed in an autoclave.

Toxins may be destroyed by several methods as shown in the table below. Some toxins are inactivated by autoclaving for one hour at 121°C. Others are inactivated by exposure to sodium hypochlorite and/or sodium hydroxide.

1. Chemical Destruction of Toxins:

When using sodium hypochlorite and / or sodium hydroxide to destroy toxins, the procedure(s) must be performed in a laboratory fume hood or a biological safety cabinet. At a minimum, personal protective equipment for all procedures should include:

• Long sleeved protective clothing (lab coat, gown)
• Gloves
• Eye protection

1. If the toxin is classified as a select agent, even in exempt amounts, notify the Biosafety Office prior to the destruction of the agent.
2. Work in a fume hood or biosafety cabinet with the sash at the lowest reasonable sash height for safe and effective work.
3. Place plastic-backed absorbent paper (bench diaper) on the work surface of the fume hood or biosafety cabinet.
4. CAREFULLY put the toxin into solution in the primary DO NOT USE A GLASS CONTAINER.
5. Place the primary container in a secondary container, such as a beaker or rack.
6. Slowly dispense an equal volume of the concentrations of sodium hypochlorite and/or sodium hydroxide designated in table 1 below into the primary container of toxin solution to be destroyed.
7. Do not replace the cap on primary container.
8. Place a “WARNING / DO NOT USE” sign on the hood/cabinet.
9. Allow a minimum 60 minutes exposure (See table 1 below for additional exposure time recommendations.)
10. Document the destruction of the toxin in the laboratory inventory log book.
11. Secure the cap on the primary DOUBLE BAG the material in zip- lock plastic bags and label it “Inactivated/denatured (TOXIN NAME)“.
12. Contact the Biosafety Office or EHS for disposal as hazardous waste.

2. Steam Sterilization (Autoclaving) of Toxins:

If acceptable as a method in table 1 below, destroy toxins by autoclaving them using the procedure outlined below:

1. If the toxin is classified as a select agent, even in exempt amounts, notify the Biosafety Office prior to the destruction of the agent.
2. In a fume hood or biological safety cabinet, loosen the cap of the primary toxin container to allow steam penetration.
3. Place the primary container into a secondary biohazard container.
4. Place the container in a loosely closed biohazard bag.
5. Place the bag in an autoclavable pan.
6. Autoclave at 121° C for 1 hour on liquid cycle (slow exhaust).
7. Document the destruction of the toxin the laboratory inventory logbook.
8. After autoclaving, allow time for materials to cool before handling.
9. Discard the autoclave bag and its containers as treated biological waste.

DO NOT use steam sterilization for destruction of any of the low molecular weight toxins (i.e. mycotoxins, marine and reptile venoms).

3. Inactivation Procedures for Selected Toxins

Allow at least a 60-minute chemical contact time for complete inactivation of toxin. Any procedure labeled “yes” is an approved procedure for inactivation of the toxin specified.

References:

1. Wannemacher W. 1989. Procedures for Inactivation and Safety Containment of Toxins. Proc. Symposium on Agents of Biological Origin, U.S. Army Research, Dev. and Engineering Center, Aberdeen proving Ground, MD. pp. 115-122
2. Factsheets on Chemical and Biological Warfare [PDF], https://www.dhs.gov/publication/biological-attack-fact-sheet
3. For complete inactivation of T-2 mycotoxin extend exposure time for liquid samples, spills, and non-burnable waste in 5% sodium hypoclorite and 0.25 N sodium hydroxide to 4 hr. Expose cages/bedding from animals exposed to T-2 mycotoxin to 0.25% sodium hypochlorite and class=GramE>0.025 N sodium hydroxide for 4 hrs.
4. For inactivation of saxitoxin, tetrodotoxin, ricin, botulinum toxin, or staphylococcal enterotoxins, expose work surfaces, solutions, equipment, animal cages, spills to 10% sodium hypochlorite for 60 minutes.
5. http://www.inchem.org/documents/pims/plant/abruspre.htm