Broad spectrum decontamination formulation and method of use

Details Broad spectrum decontamination formulation and method of use Broad spectrum decontamination formulation and method of use

2000-02-16

2003-02-25

Gupta, Yogendra N. (Department: 1751)

Hazardous or toxic waste destruction or containment

Containment

Solidification, vitrification, or cementation

C588S020000, C510S110000, C510S420000, C510S426000, C510S435000, C510S509000

Reexamination Certificate

active

06525237

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to decontamination formulations and more particularly to formulations for decontaminating surfaces and/or materials contaminated with chemical and/or biological warfare agents and/or nuclear radioactive particles.
BACKGROUND OF THE INVENTION
Chemical (CW) and biological (BW) warfare agents (collectively CB agents) are becoming an increasingly important part of defence weaponry. Further, radioactive fallout or dusts have also been of concern, since nuclear devices have been added to military arsenals.
Nuclear/Radioactive Particles
Nuclear or radioactive particles pose a significant threat to personnel due to the effects of ionizing radiation. In addition to the initial release of radiation from a nuclear device and radiation caused by emission from materials which have become radioactive as a result of the initial detonation, inhalation of radioactive dusts or particulate matter can lead to significant numbers of casualties long after the attack. As with BW agents, secondary aerosolization poses an ever-present threat and results in the need to wear protective masks for extended periods of time.
Biological Warfare (BW) Agents
BW agents are characterized as microorganisms including bacteria, viruses and fungi. They are particulate in nature and present a significant hazard long after an attack through formation of secondary aerosols which are inhaled. Unlike CW, BW agents may not result in immediate effects. A lapse of hours, days or weeks may occur before the full extent of their effects become apparent. In the case of certain BW agents, like anthrax, spore production ensures that the BW agent can remain in the environment for years while retaining biological activity. While BW agents may be readily removed from a surface they are often merely repositioned in the underlying environment and remain hazardous if disturbed.
Chemical Warfare (CW) Agents
Three main types of persistent and semi-persistent CW agents exist. They are vesicants and two families of nerve gases, V and G, as outlined in Table I.
TABLE I
Family
Agent
Acronym
Formula
Vesicants
Sulfur Mustard
HD
Cl CH
2
CH
2
S CH
2
CH
2
Cl
Nitrogen Mustard
HN-1
(CH
2
CH
2
Cl)
2
NC
2
H
5
Nitrogen Mustard
HN-2
(CH
2
CH
2
Cl)
2
NCH
3
Nitrogen Mustard
HN-3
N(CH
2
CH
2
Cl)
3
Lewisite
L
ClCH═CHAsCl
2
G
Tabun
GA
C
5
H
11
N
2
O
2
P
Sarin
GB
C
4
H
10
FO
2
P
Soman
GD
C
7
H
16
FO
2
P
V
VX
CH
3
CH
2
O—P(O)(CH
3
)—
SCH
2
CH
2
N(C
3
H
7
)
2
Vesicants act as blistering agents that attack skin and mucous membranes and are lethal at high doses.
The V agents are in the phosphorylthiocholine class of compounds, while the G agents are phosphonofluoridates. Both share the same reaction chemistry as organophosphorous esters and pesticides. Nerve agents act on the central nervous system by reacting with the enzyme acetylcholinesterase to cause respiratory collapse, convulsions and death.
G-agents tend to be semi-volatile and toxic by inhalation and percutaneous absorption, while V-agents are relatively non-volatile, persistent, and very toxic by the percutaneous route.
The threat of the use of CB agents and nuclear devices has prompted the need to develop protective and decontamination measures for personnel and military hardware.
Decontamination—Radioactive Particles
As radioactive particles are nuclear in origin, decontamination cannot deactivate the radioactive hazard. However, the removal of the particulate matter from equipment can significantly reduce aerosolization potential and the spread of the radioactive hazard to clean areas. Generally, removal of the particulate matter requires the encapsulation of the particles and subsequent removal of the encapsulated material from equipment surfaces.
Decontamination—BW Agents
In the case of BW agents, personal protective equipment such as masks, protective suits etc. are the primary defence against contamination. In some cases, where time and environmental conditions exist, natural weathering such as exposure to sunshine, heat and moisture may destroy the BW agent.
For many BW agents, standard disinfectants can be very effective as decontaminants. An example is the use of hypochlorites or chlorine gas in the treatment of water supplies, swimming pools and in sanitizing food preparation equipment. Active chlorine is considered to be among the most economical yet most effective broad spectrum BW agent decontaminant. Hypochlorites have been shown to be effective against some of the most robust BW agents such as anthrax spores as well as viruses and bacteria. Hypochlorous acid is superior to that of hypochlorite anion as it more readily crosses the cell membrane. Thus, it would be advantageous to perform decontamination of BW agents in a slightly acidic, neutral or slightly basic media where hypochlorous acid is a dominant active component rather than in a strongly basic solution, where hypochlorite anion is the predominant species.
Decontamination—CW Agents
CW agent decontamination presents a number of challenges. Following a CW agent attack, the semi-persistent or persistent nature of these agents allows them to remain toxic, not only during dissemination, but also for many hours or even days after the attack. The principal hazard occurs through direct inhalation of the vapor off-gassed from the agent or through physical contact with the skin or mucous membranes, through which it is absorbed.
Generally
Ideally, a decontamination formulation should be broad-spectrum in nature, as in most cases the actual nature of the warfare agents being faced is not known. It should be compatible with, and non-corrosive to, equipment used in its application as well as to the equipment to be decontaminated. It should not soften nor damage paints, coatings, polymeric seals or gaskets or transparencies such as windscreens. It should not interfere with in-service monitoring equipment used to verify the effectiveness of the decontamination or to locate residual contamination. It should be easy to prepare, easy to apply and remove, and remain stable for reasonable lengths of time after preparation. It is highly desirable that it adhere to and coat vertical surfaces for sufficient periods of time for agent desorption from the surface and detoxification, yet be easy to remove by evaporation or by rinsing. If used in combination with a surfactant, the decontamination formulation should not compromise the integrity of the foam. It should be of low toxicity, be non-flammable and have a low impact on the environment in order that training can be realistically and frequently performed. Preferably, the formulation should be based in media capable of solubilizing and supporting detoxification of the sparingly soluble CW agents and solubilizing and degrading polymeric thickeners in which the CW agent may reside. Often, these thickeners have high adherence to surfaces and are more difficult to remove than the agents in neat form. Where possible, the decontaminant should be in a concentrated form for mixing with water or other suitable diluent in order to reduce logistical loads on transport and storage and should be readily mixed. For economic reasons it should be formulated from compounds that are readily available in large quantities and be stable in storage for long periods of time. Ideally, the media for dilution should be water or seawater as, in most cases, it is readily available on site and is non-toxic.
Prior art decontamination formulations have taken advantage of the fact that CW agents can generally be oxidized or hydrolyzed, dependent upon their structure, to result in non-toxic products. Many BW agents are readily decontaminated by those same active ingredients, such as hypochlorite and radioactive particles are encapsulated by the surfactants utilized to cause the formulations to adhere to vertical surfaces and are removed and diluted during the removal of the formulation, generally by washing.
In the case of V agents, mustards and biological warfare agents, oxidation has been most successful. Various reactants such as hypochlorites, permanganates, N-chloro and

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