Methyl [(dimethoxyphosphinothioyl)thio]acetate

Guidance on Safe Use

First-aid measures

Emergency and First Aid Procedures       

Call a doctor (physician), clinic or hospital immediately. Explain that the victim has been exposed to an organophosphorus compound which can react with a range of compounds under formation of cholinesterase inhibitors - and describe his/her condition. Move the victim immediately from the area where MPEM is present.

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

If swallowed and the exposed person is conscious, make him/her vomit quickly. Make the exposed person drink 1 or 2 glasses of water and induce vomiting by touching the back of the throat with a finger. Never give anything by mouth to an unconscious person. Get medical attention immediately.

In case of contact, immediately flush eyes or skin with plenty of water while removing contaminated clothing and shoes. See physician immediately.

      

Note to Physician              

MPEM can react with a range of compounds under formation of cholinesterase inhibitors which affect the central and peripheral nervous systems producing respiratory depression.

Cholinesterase Inhibition - Treatment

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

      

Antidote: If symptoms (see above) are present, administer atropine sulphate, which is often 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 not a substitute for atropine sulphate. Treatment with oxime should be maintained as long as atropine sulphate is administered.

      

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

      

Relapse can occur after initial improvement.

VERY CLOSE SUPERVISION OF THE PATIENT IS

INDICATED FOR AT LEAST 48 HOURS, DEPENDING ON THE SEVERITY OF 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 or Byproducts in a Fire       

The essential breakdown products are dimethyl sulphide, sulphur dioxide, carbon monoxide, carbon dioxide and phosphorus pentoxide.

Accidental release measures

Steps to Be Taken in Case of Spill       

Small liquid spills on the floor or other impervious surface should be swept up by means of an inert absorptive material such as hydrated lime, sawdust, Fuller’s earth or other absorbent clays. Scoop into proper containers and dispose of in accordance with the instructions provided under Disposal . Rinse area with soda lye.

Large liquid spills on the floor or other impervious surface should be contained or diked and then absorbed with an inert absorptive material such as hydrated lime, sawdust, Fuller’s earth or other absorbent clays. Collect the contaminated absorbent, place in a metal drum and dispose of in accordance with the instructions provided under Disposal. Rinse area with soda lye.

Large spills that soak into the ground should be dug up, placed in metal drums and disposed of in accordance with instructions provided under Disposal.

MPEM can be hydrolysed in water by heating and adjusting the pH (alkaline). MPEM may also be disposed of through proper incineration.

Handling and storage

In an industrial environment it is imperative to avoid all personal contact with the substance by handling and storing it only in closed systems with remote system control.  

Adequate ventilation or local exhaust ventilation is required. The exhaust gases should be filtered or treated otherwise.

Avoid contact with eyes, skin or clothing. Avoid breathing vapour and avoid exposure of eyes to vapour as well.

Protect against moisture, air access and strong heat from sunshine or other source, e.g. fire.

MPEM is stable when stored in coated, unopened drums at temperatures not exceeding 20-25°C.

Storage at temperatures not exceeding 25°C is recommended. It should never be heated above 55°C. Local heating above this temperature should be avoided as well. Protect against strong heat from sunshine or other source, e.g. fire.

MPEM will decompose rapidly when heated to temperatures above 100°C, significantly increasing the risk of explosion.

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

Transport information

Shipping

SpecialProvisions

Shipping

Remarks

Marine transport (UN RTDG/IMDG)

Shipping

Remarks

Shipping

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, for example in the case of an accident. Consider the need to render equipment or piping systems non-hazardous before opening.

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.

In case of insufficient ventilation, workers should put on officially approved respiratory protection equipment with a combination filter type against acids and including particle filter and wear appropriate chemical resistant clothing to prevent skin contact.

Stability and reactivity

MPEM is stable when stored in coated, unopened drums at temperatures not exceeding 20-25°C.

Storage at temperatures not exceeding 25°C is recommended. It should never be heated above 55°C. Local heating above this temperature should be avoided as well. Protect against strong heat from sunshine or other source, e.g. fire.

MPEM will decompose rapidly when heated to temperatures above 100°C, significantly increasing the risk of explosion.

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

Disposal considerations

Waste Disposal Method

Spill and waste disposal procedures in accordance with state and local regulations must be followed.

Do not contaminate water, food or feed by storage and disposal.

Container Disposal

Triple rinse (or equivalent). Then offer for recycling or reconditioning, or puncture and dispose of in a sanitary landfill. However, procedures in accordance with state and local authorities must be followed.