O,O-dimethyl phosphorochloridothioate

Guidance on Safe Use

First-aid measures

The first symptom to appear will be irritation for all routes of exposure. In case of exposure, do not wait for symptoms to develop. Immediately, start the recommended procedures below  and call a physician, poison centre or hospital. Describe the type and extent of exposure and the victim's condition.

If any of the signs of cholinesterase inhibition occures, explain that the victim has been exposed to O,O-dimethyl phosphorochloridothioate, a chemical which may cause cholinesterase inhibition. Immediately remove the exposed person from the area where the product is present.

If breathing has stopped, immediately start artificial respiration and maintain until a physician takes charge of the exposed person.

Inhalation: If experiencing any discomfort, immediately remove the exposed person from exposure. Get medical attention immediately if symptoms develop.

Eye contact: Immediately flush with plenty of water or eyewash solution, occasionally opening eyelids, until no evidence of chemical remains. Remove contact lenses after a few minutes and flush again. See physician immediately.

Skin contact: Immediately flush with plenty of water while removing contaminated clothing and footwear. Wash with water and soap. See physician immediately if irritation develops.

Ingestion: If the exposed person is conscious, let him/her rinse mouth with water and let him/her drink several glasses of water or milk, but do not induce vomiting. If vomiting does occur, give fluids again. Never give anything by mouth to an unconscious person. Get medical attention inmmediately.

Note to physician: Irritated skin should be treated as usual against effects of acids or acid fumes. In case lungs are affected watch for pulmonary oedema and possible cholinesterase inhibition.

Cholinesterase inhibitors affect the central and peripheral nervous systems and produce respiratory depression.

Cholinesterase inhibition - treatment: If cholinesterase inhibition occurs, the following treatment may be applied:

Decontamination procedures such as whole body washing, gastric lavage and administration of activated charcoal are often required.

Antidote: Administer atropine sulphate, which often is a lifesaving antidote, in large doses, TWO to FOUR mg intravenously or intramuscularly as soon as possible. Repeat at 5 to 10 minute intervals until signs of atropinisation appear and maintain full atropinisation until all organophosphate is metabolised.

Obidoxime chloride (toxogonin), alternatively pralidoxime chloride (2-PAM), may be administered as an adjunct to, but a substitute for atropine sulphate. Treatment with oxime should be maintained as long as atropine sulphate is administrered.

At first sign of pulmonary oedema, the patient should be given supplementary oxygen and treated symptomatically.

Relapse may occur after initial improvement. VERY CLOSE SUPERVISION OF THE PATIENT IS INDICATED FOR AT LEAST 48 HOURS, DEPENDING ON THE SEVERITY OF THE POISONING.

Fire-fighting measures

Extinguishing media and procedure: Dry chemical or carbon dioxide for small fires, water spray or foam for large fires.

Use water spray to keep fire-exposed containers cool. Approach fire from upwind to avoid hazardous vapours and toxic decomposition products. Fight fire from protected location or maximum possible distance. Avoid heavy hose streams. Dike area to prevent water runoff. Firemen should wear self-contained breathing apparatus and protective clothing.

Hazardous decomposition in a fire: The essential breakdown products are volatile, toxic, malodorous, irritant and inflammable compounds such as hydrogen sulphide, hydrogen chloride, sulphur dioxide, methyl mercaptan, dimethyl sulphide, phosphorus pentoxide, carbon monoxide and carbon diooxide.

Accidental release measures

Observe all personal protection and safety precautions. Depending on the magnitude of the spill, this may mean wearing face shield or eye protection, Chemical resistant clothing, gloves and boots when cleaning up spills. Personal exposure by splashing must be avoided.

Steps to be taken in case og spill: It is recommended to have a predetermined plan for the handling of spills. Empty, closable vessels (not metal) for the collection of spills should be available.

Stop the source of the spill immediately if safe to do so. Contain the spill to prevent any further contamination of surface, soil or water. Remove sources of ignition.

Spills on the floor or other impervious surface should be contained or diked and then absorbed onto an absorptive material such as universal binder, hydrated lime, Fuller's earth or other absorbent clays. Collect the contaminated absorbent in suitable containers. Rinse area with soda lye or much water. Absorb wash liquid with absorbent and transfer to suitable containers as well. Wash waters must be prevented from entering surface water drains.

Large spills which soak into the ground should be dug up and transferred to suitable containers.

Spills in water should be contained as much as possible by isolation of the contaminated water. The contaminated water must be collected and removed for treatment or disposal. Uncontrolled discharge into water courses must be alerted to the appropriate regulatory body.

The used containers should be properly closed and labelled.

Handling and storage

In an industrial environment it is recommended to avoid all personal contact with the product, if possible by using closed sytems with remote system control. Otherwise, the material should preferably by handled by mechanical means. Adequate ventilation or local exhaust ventilation is required. The exhaust  gases should be filtered or treated otherwise. Splashing and the formation of aerosol or mist must be avoided.

Avoid contact with eyes, skin or clothing. Avoid breathing vapour. Wash thoroughly after handling. Remove contaminated clothing.

MP-2 is relatively stable when stored in coated, unopened drums at temperatures not exeeding 20 - 25°C.

MP-2 hydrolyses in presence of small quantities of water and becomes corrosive to iron and many other metals. Storage should take place in unopened drums or in properly protected tanks (e.g. lined with glass, polypropylene, epoxy or phenolic resin). If free from moisture, tanks of acid-resistant steel, such as 316 or V4A, can also be employed.

Do not contaminate air, water, or foodstuffs by storage or disposal.

Storage at temperatures not exeeding 25°C is recommended. MP-2 should never be heated above 55°C and also local heating above this temperature should be avoided. Protect against strong heat from sunshine or other source, e.g. fire.

Heating above 55°C may only take place in connection with further processing of MP-2 and then only temporarily and under controlled conditions.

Transport information

Land transport (UN RTDG/ADR/RID)

UN number:

2267

Shipping information

Proper shipping name and description:

Dimethylthiophosphoryl chloride

Chemical name:

O,O-dimethyl ester phosphorochloridothioic acid

Language:

English

Labels:

T+, very toxic

SpecialProvisions

Shipping

Remarks

Marine transport (UN RTDG/IMDG)

UN number:

2267

Shipping information

Proper shipping name and description:

Dimethylthiophosphoryl chloride

Chemical name:

O,O-dimethyl ester phosphorochloridothioic acid

Labels:

T+, very toxic

Remarks

Air transport (UN RTDG/ICAO/IATA)

UN number:

2267

Shipping information

Proper shipping name and description:

Dimethylthiophosphoryl chloride

Chemical name:

O,O-dimethyl ester phosphorochloridothioic acid

Labels:

T+, very toxic

Remarks

SpecialProvisions

Exposure controls / personal protection

When used in a closed system, personal protection equipment will not be required. The following is meant for other situations, when the use of a closed system is not possible, or when it is necessary to open the system. Consider the need to render equipment or piping systems non-hazardous before opening.

Inhalation of vapours must be avoided completely, preferentially by mechanical means. If protection of workers by mechanical means is not possible, a face mask or officially approved respiratory protection equipment with a universal filter type including particle filter must be used.

Wear chemical resistant gloves, such as barrier laminate, butyl rubber or nitrile rubber. The breakthrough times of these materials for this product are unknown. Generally, however, the use of protective gloves will give only partial protection against dermal exposure. Small tears in the gloves and cross-contamination can easily occur. It is recommended to shift the gloves frequently and to limit the work to be done manually.

Wear face mask rather than safety glasses or goggles. It is recommended to have an eye wash fountain immediately available in the workplace when there is a potential for eye contact.

Wear appropriate chemical resistant clothing to prevent skin contact.

Persons working with this product for a longer period should have frequent blood tests of their cholinesterase levels. If the cholinesterase level falls below a critical point, no further exposure should be allowed until it has been determined by means of blood tests that the cholinesterase level has returned to normal.

Keep all unprotected persons and children away from working area.

Avoid contact with eyes, skin or clothing. Avoid breathing vapour or mist.

Remove contaminated clothing immediately. Wash thoroughly after handling. Before removing gloves, wash them with water and soap. After work, take off all work clothes and footwear. Take a shower, using water and soap. Wear only clean clothes when leaving job. Wash protective clothing and protective equipment with water and soap after each use.

Persons working with this product for a longer period should have frequent blood tests of their cholinesterase levels. If the cholinesterase level falls below a critical point, no further exposure should be allowed until it has been determined by means of blood tests that the cholinesterase level has returned to normal.

Keep all unprotected persons and children away from working area.

Avoid contact with eyes, skin or clothing. Avoid breathing vapour or mist.

Remove contaminated clothing immediately. Wash thoroughly after handling. Before removing gloves, wash them with water and soap. After work, take off all work clothes and footwear. Take a shower, using water and soap. Wear only clean clothes when leaving job. Wash protective clothing and protective equipment with water and soap after each use.

Avoid discharge to the environment.

Stability and reactivity

MP-2 will decompose rapidly when heated to temperatures above 80°C, significantly increasing the risk of explosion.

The decomposition is dependent on time as well as temperature due to self-accelerating exothermic and autocatalytic reactions. The reactions involve rearrangements and polymerisation releasing volatile malodorous and inflammable compounds such as methyl mercaptan and dimethyl sulphide.

Avoid strong alkalis. An acid-base neutralisation reaction can be hazardous because of heat release.

Amines and strong oxidising compounds.

The substance can corrode metals.

Disposal considerations

Waste material can be removed by controlled discharge to a waste water treatment plant. Other possible methods of disposal are controlled incineration with flue gas scrubbing or removal to a licensed chemical destruction plant.

Do not contaminate water or foodstuffs by storage or disposal.

Triple rinse (or equivalent) and offer for recycling or reconditioning. Alternatively, the packaging can be punctured to make it unusable for other purposes and then be disposed of in a sanitary landfill.

Disposal of waste and packagings must always be in accordance with all applicable local regulations.