Caustic Soda has a H314 ( causes severe skin burns and eye damage) but no H4xx Hazard Statement ,  any one know why not when in part 6 of an SDS it states

"ENVIRONMENTAL PRECAUTIONS Spillages or uncontrolled discharges into watercourses must be IMMEDIATELY alerted to the Environmental Agency or other appropriate regulatory body."

Edited by user 06 March 2018 15:46:56(UTC)  | Reason: and x to many

Sorry what is H4xxx?

https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/162534

Caustic Soda monohydrate has 23 notified classifications on the ECHA substance profile all assigning Skin Corrosive Category 1A for which the hazard statement is H314 pictogram GHS05  (corrosive) and signal word Danger

Your supplier will have devised the information upon their Safety Data Sheet (and labelling) so it is probably best to ask them especially if competitors are providing different information

Forgot to mention if this is a US originated/formatted SDS they are not obliged to classify or include environmental hazards as SDS come under OSHA regulation whilst the environment is under EPA control

Edited by user 06 March 2018 15:38:42(UTC)  | Reason: added comment regarding US SDS

Hazard statements under GHS ie H4xx are:

H400: Very toxic to aquatic life

H401: Toxic to aquatic life

H402: Harmful to aquatic life

H410: Very toxic to aquatic life with long-lasting effects

H411: Toxic to aquatic life with long-lasting effects

H412: Harmful to aquatic life with long-lasting effects

H413: May cause long-lasting harmful effects to aquatic life

H420: Harms public health and the environment by destroying ozone in the upper atmosphere

And caustic soda is none of the above-

Caustic soda is used as drain/pipe cleaner hence why it doesn't have your H4xx Hazard Statement.

Toxic is a specific technical definition. A toxic substance is something that is absorbed by the organisms and causes adverse physiological effects ie it kills them. Harmful is similar but is less likely to kill them. Caustic soda is corrosive not toxic and thus there is no Hazard Statement 4xxx for that as it very quickly disperses and essentially leaves no residue. A pesticide or herbicide might be classified as toxic to aqueous life forms as it will be absorbed by the organisms cause and long term harm. Dumping a tanker load of anything (including strangely pure water) into a water course will cause some ecological harm, but they are not listed under the GHS regs.

In the UK you cannot dump ANYTHING into watercourse even water without permission from the Environment Agency, let alone a tanker full of caustic soda.

I think that the issue may stem from the fact that the H400 range of warnings is derived from things like Chemical Oxygen Demand and Biological Oxygen Demand - from memory (and it is from a long time ago!!) I don't think Caustic Soda triggers the limits on these.

Refer to one of the principle drivers behind the REACH/CLP regulations - consistent information throughout the supply chain

Sodium Hydroxide was in the first phase of CLH (Harmonised Classification) added to table 3 of the CLP regulation

Based on all available evidence and submission only H314 applies to this substance in its purer forms >5% (lower classifications apply the more diluted it becomes and below 0.5% no classification applies)

https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/134413