If a metham solution is acidified, it will release carbon disulphide, a toxic,
volatile liquid, FP<-30°C, which will catch fire if the vapours come in
contact with any surface at 100°C or higher. The flammable range for carbon
disulphide vapour is 1 to 50%v/v in air.
10. STABILITY AND REACTIVITY
Hazardous Reactions Avoid oxidising agents, acids and heavy metal salts.
Metham sodium is stable in concentrated solution, but unstable when diluted,decomposition being
promoted by soil, acids and heavy metal salts. The solution is corrosive to
brass, copper and zinc. The activity of metham sodium is due to the formation
of methyl isothiocyanate in contact with soil.

Methyl isothiocyanate is a volatile, highly toxic material, its presence is
detected by its extremely irritating effects on eyes, causing copious tear
formation.

May emit toxic fumes of cyanide and nitrogen oxides if material is
involved in fires or subjected to extreme heat. Also decomposes in acids
with release of carbon disulphide.

Carbon disulphide is toxic and highly flammable.

12. ECOLOGICAL INFORMATION
Persistence /
Degradability
In soil, rapidly decomposes to methyl isothiocyanate, which is volatile and
quickly evaporates. Methyl isothiocyanate is a lachrimator, causing stinging
and watering of the eyes.
Known Harmful
Effects on the Environment
The product is a marine pollutant for sea transport.
Other Precautions Do not contaminate dams, waterways or sewers with this product or the
containers which have held this product.
Environ. Protection Spray drift should be avoided, read the label for more information.
Acute Toxicity - Fish The following is data for the active ingredient, metham sodium.
LC50 (96hr) for guppy is 4.2 mg/l.
LC50 (96hr) for bluegill sunfish is 0.39 mg/l.
LC50 (96hr) for rainbow trout is 0.079 mg/l.
Acute Toxicity - Other Organisms
Dietary LC50 (5 days) mallard duck and japanese quail is >5000 mg/kg