Select Toxin Guidance: Regulatory Exclusions (Section 3(d))
Nontoxic select toxins
The Select Agent Regulations (SAR) state that nontoxic select toxins are excluded from these regulations [7 CFR §331.3(d)(2)external icon; 9 CFR §121.3(d)(2)external icon and 9 CFR §121.4(d)(2)external icon; 42 CFR §73.3(d)(2)external icon and 42 CFR §73.4(d)(2)external icon]. A “nontoxic” select toxin is no longer capable of exerting its toxic effect. For regulated nucleic acids, the term “nontoxic” means that the nucleic acids are no longer capable of producing a toxic select toxin without further genetic manipulation. In general, the methods used to render a select toxin nontoxic may fall into one of the following categories:
- Physical, like heat or irradiation
- Enzymatic, like a lysozyme
- Chemical
Different processes (e.g. heat, radiation, or chemicals) work by different mechanisms. For a select toxin to be properly characterized as nontoxic after treatment, exposure to the select toxin must not result in toxicity or express a functional select toxin from regulated nucleic acids. A select toxin shall be considered nontoxic only after it has been subjected to a method that has been validated to be effective on a specific toxin. The individual or entity possessing the select toxin or regulated nucleic acid is responsible for validating non-toxicity.
Additional information on nontoxic toxins and rendering samples free of select toxins is available on the FSAP website.
Animals Exposed to a Select Toxin
42 CFR §73.3(d)(4)external icon of the SAR addresses animals inoculated with or exposed to an HHS select toxin. Even after an animal has been inoculated with or exposed to a select toxin (for example, by inhalation, dermal absorption, or ingestion), the animal is not considered a “select toxin” and does not need to be housed in a registered space.
For dermal exposure, any residual select toxin on the animal must be removed before the animal could be transferred to unregistered space. The residual select toxin wiped off the animal should be treated, similarly to select toxin material not used during injection of an animal.
If the excess select toxin used for inoculation or exposure is retained and not destroyed as waste, it must be accounted for. The number of animals inoculated with or exposed to a select toxin does not need to be recorded for long-term storage.
However, the select toxin is regulated under the SAR until it is injected into or exposed to the animal. This includes storage or use of the select toxin (e.g., injection or exposure procedure). The room where the inoculation or exposure of animals with an HHS select toxin occurs may be assessed using laboratory biosafety level criteria instead of animal laboratory biosafety level criteria. These rooms must be included on an entity’s registration. Once the inoculation or exposure has occurred, the animals can be moved to an unregistered room.
If the toxin preparation used to inoculate or expose animals contains viable Botulinum neurotoxin producing species of Clostridium, the material and animal is regulated unless a validated method to remove the organism from the toxin preparation is used.
Toxins in their Natural Environment
Sections 3(d)(1), 4(d)(1) of Part 73 and Part 121 provide for exclusion of select toxins in their natural environment:
Any select toxin that is in its naturally occurring environment provided the select toxin has not been intentionally introduced, cultivated, collected, or otherwise extracted from its natural source.
Please see the natural environment table below for a description of the natural environments for each regulated toxin.
The chart below provides the natural environment for select toxins which would not be subject to the SAR.
Select Toxin |
Natural Environment |
|---|---|
| Abrin | Seeds of the plant Abrus precatorius (rosary peas) including rosary pea mash. |
| BoNT | Botulinum neurotoxin producing species of Clostridium for which no additional procedures have been done to collect, extract, amplify, or produce BoNT. |
| Alpha-conotoxins | Cone snails (Conus spp.) |
| DAS |
|
| Ricin | Castor beans (Ricinus communis) including castor bean mash, which is the by-product of castor oil production that contains crushed plant material. |
| STX | Species of cyanobacteria and marine dinoflagellates and filter feeding shellfish that have concentrated STX from these sources. |
| SE subtypes A, B, C, D, E | Staphylococcus aureus strains that produce SE A, B, C, D, E subtypes for which no additional procedures have been done to collect, extract, amplify, or produce SE A, B, C, D, E subtypes. |
| T-2 toxin |
|
| TTX | Aquatic animals and amphibians and organs that contain TTX so long as no additional extraction of TTX occurs. |
Regulation point for each select toxin
The chart below provides the regulatory starting point for select toxins extracted or collected from the natural environment. Synthesized toxic select toxins in excess of the regulatory threshold are regulated at all times.
Select Toxin |
Regulatory Starting Point (so long as the quantity under the control of a principal investigator, treating physician or veterinarian, or commercial manufacturer or distributor is in excess of the regulatory threshold) |
|---|---|
| Abrin | When crushed Abrus precatorius (rosary peas) mash is further processed, resulting in the extraction or concentration of abrin, the abrin containing product of this procedure is regulated. |
| BoNT | Intentional BoNT collection, extraction, amplification, or production. For licensed products that contain BoNT (e.g. BOTOX), once BoNT is vialled in its final formulation and to be used for medical purposes as stipulated by its license, it is no longer regulated. |
| Alpha-conotoxins | Soluble peptides of the appropriate amino acid sequence extracted from the venom bulb of cone snails that have been treated with proteases to properly fold and activate alpha-conotoxins. |
| DAS | Extraction from culture supernatant or contaminated food in organic solvent. |
| Ricin | When castor bean mash is further processed, resulting in the extraction or concentration of ricin, the ricin-containing product of this procedure is regulated. |
| STX | Dinoflagellate or cyanobacterial pellet, contaminated fish or shellfish that is sonicated or otherwise disrupted and acidified water is added to extract STX. |
| SE subtypes A, B, C, D, E | Intentional SE subtypes A, B, C, D, E collection, extraction, amplification, or production. |
| T-2 toxin | Extraction from culture supernatant or contaminated food in organic solvent. |
| TTX | Extraction from aquatic animals and amphibians and organs that contain TTX in acidified water or organic solvent. |
Toxins Identified in an Original Food or Clinical Sample
Section 3(d)(9)external icon of Part 73, Part 121, and Part 331 of the SAR provides for exclusion of select toxins identified in an original food sample or clinical sample.
Original food samples and clinical samples are those specimens that are submitted to laboratories for diagnosis or verification purposes to identify or verify a biological toxin. For example, an original food sample could be a container of potato salad or juice. An original clinical sample could be serum or stool from a patient. Laboratories that test food and clinical samples for the presence of toxins generally do not know the level of toxin in a sample and do not extract and purify a toxin as part of their studies. This exclusion does not pertain to samples (food or otherwise) spiked with known select toxin.
Toxins as a byproduct
For those laboratories that are not exempt under §73.5(a) and §73.6(a), Botulinum neurotoxin that is produced as a byproduct in the study of Botulinum neurotoxin producing species of Clostridium is not regulated so long as the toxin has not been intentionally cultivated, collected, purified, or otherwise extracted, and the material containing the toxin is rendered non-toxic and disposed of within 30 days of the initiation of the culture. Botulinum neurotoxin producing species of Clostridium are regulated and the byproduct exclusion only pertains to the toxin. Further, if the material containing the toxin is retained past 30 days the toxin in the material will be subject to the regulations, including inventory requirements.
Select Toxins modified to be less potent or toxic
An entity or individual may submit a written request that FSAP exclude a select toxin modified to be less potent or toxic from the select agent regulations. In general the methods that render a select toxin less potent or toxic are genetic modifications (recombinant or synthetic) such as deletions, point mutations, and chimeras. Typically a select toxin needs to be tested in relevant animal models before their reduction in potency or toxicity can be validated.
The request should contain the rationale for the exclusion of the select toxin and scientific references or supporting documentation that demonstrates the modified select toxin does not pose a severe threat to public health and safety. The request should include:
- Documented history of not causing toxicity in humans, or relevant animal models, including quantitative measures demonstrating a reduction in potency or toxicity.
- Defined genetic mutations or alterations known to reduce potency or toxicity in humans or relevant animal models.
- Data showing the mutations have a low frequency of reversion to wild-type potency or toxicity.
- Level of difficulty in engineering the modified toxin to restore wild-type potency or toxicity.
FSAP will issue a written decision granting or denying the request. The exclusion will be effective upon notification to the applicant.
If an excluded modified select toxin is subjected to any manipulation that restores or enhances its toxic activity, the resulting select toxin will be subject to the select agent regulations [See 42 CFR §§ 3(e)(2), 4(e)(2)].
For more information on exclusions and how to apply please see the Select Agents and Toxins Exclusion list and the Exclusion Guidance Document.