Reading a Safety Data Sheet: GHS, CAS Numbers and Your Own Labels

The single most useful safety document you will ever own is a PDF you can download in twenty seconds and that most people never open. This page is about reading it, and about the two things that make it readable: a system of pictograms and coded statements that means the same thing in every country, and a registry number that identifies a substance when its name will not.

What a safety data sheet is, and what it is not

A safety data sheet describes a supplied product at a supplied concentration, written by the company that put it in the bottle. It is not a textbook about a substance, it is not a general account of a chemical class, and it is not this course.

That distinction does most of the work. ILFORD’s index of sheets says it plainly: they relate to the products in the form that is actually sold. A sheet for a rapid fixer concentrate is about that concentrate. Dilute it 1+4 and you are handling something whose classification may differ, because classification depends on concentration — which is why the harmonised European entry for acetic acid is titled, literally, “acetic acid … %”, with the percentage left for the supplier to fill in.

Three consequences follow, and the course applies all three.

1. The sheet for the product in your hands governs. Not the sheet for the same product from a different supplier, not last year’s sheet, and not this page.
2. This course never replaces a current sheet. Where it quotes a classification it names the source and the date, and where a page and a sheet disagree, the sheet wins.
3. Re-check when you reorder. OSHA’s standard requires a manufacturer or importer to add significant new hazard information to a sheet within three months, and to supply the updated sheet with the first shipment after it changes. That mechanism only reaches you if you look.

The sixteen sections

The order and the headings are fixed. OSHA’s Hazard Communication Standard sets them out as the minimum content of a sheet, in the order they must appear; Kodak’s own handling guidance for photographic laboratories lists the same sixteen categories, which is a useful cross-check that this is the industry-wide shape rather than one jurisdiction’s idea.

The sixteen sections, and where a photographer actually looks

1. 2Hazards identification — read first: pictograms, signal word, H and P statements
2. 4First-aid measures — read first: what to do per route, before you need it
3. 7Handling and storage — read first: incompatibilities in practice, container, conditions
4. 8Exposure controls and personal protection — read first: gloves, eye protection, ventilation, exposure limits
5. 10Stability and reactivity — what it must not meet, and what it decomposes into
6. 13Disposal considerations — the chemistry of the waste; your local rules still govern
7. 16Other information — the revision date you write into your inventory

Sections 1, 3, 5, 6, 9, 11, 12, 14 and 15 are not unimportant; they are the ones you consult for a reason rather than as routine.

The four to read before the cap comes off are 2, 4, 8 and 7, in that order: what it can do, what to do if it does it, what to wear, and how to keep it. Sections 10 and 13 are read before it joins your shelf and before it becomes waste. Everything else is consulted when a question arises.

✦A blank is not an answer, and a sheet must say so

OSHA requires that where no relevant information is found for a sub-heading, the sheet is marked to say so. A sheet with silent gaps is a badly written sheet. “No data available” under a sub-heading is a legitimate answer that you can act on; an empty space tells you nothing about whether anyone looked.

GHS: pictograms, signal words, H and P

The Globally Harmonized System is the reason a bottle bought in Manchester, Munich or Milwaukee carries the same diamond. PubChem’s GHS reference summarises the current revision, GHS Rev. 11 of 2025, and it is the list this course works from.

The nine pictograms

Code	Formal name	Hazard class it stands for	Where you meet it in this course
GHS01	Exploding Bomb	explosives	nowhere in normal practice; the silver nitrate page explains the one route by which a photographer could make an explosive by accident
GHS02	Flame	flammables	glacial acetic acid, isopropanol, ethanol
GHS03	Flame Over Circle	oxidisers	silver nitrate, and the persulfate and permanganate reducers of later parts
GHS04	Gas Cylinder	gases under pressure	nowhere; no compressed gas is used
GHS05	Corrosion	corrosives, to skin, eyes or metals	sodium hydroxide, glacial acetic acid, silver nitrate, concentrated developer concentrates
GHS06	Skull and Crossbones	acute toxicity	nothing in Levels A or B; it marks the substances the course teaches as history only
GHS07	Exclamation Mark	irritants, harmful, skin sensitisers	metol, phenidone, potassium bromide, sodium carbonate — the commonest chip on a photographic shelf
GHS08	Health Hazard	serious longer-term health hazards	hydroquinone, metol
GHS09	Environment	hazardous to the aquatic environment	silver salts, metol, hydroquinone; the reason the waste page exists

!Two pictograms in particular are misread

GHS07, the exclamation mark, is not the mild one. It carries skin sensitisation (H317) as well as irritation, and sensitisation is permanent once acquired. GHS08, the health hazard, is not the severe version of GHS07. It marks a different kind of harm entirely — carcinogenicity, mutagenicity, reproductive toxicity, organ toxicity from repeated exposure — which is invisible in the short term and therefore easy to discount. Metol carries both, and neither of them will hurt you today.

Signal words

Exactly two exist: Danger for the more severe categories and Warning for the less severe. Only one appears on a label, and it is the more severe of the two if both would apply. A category that warrants neither carries no signal word. Sodium hydroxide’s harmonised entry is Danger; sodium carbonate’s is Warning; sodium thiosulfate has neither, because it has no classification.

H and P statements

H statements say what the hazard is. P statements say what to do about it: prevention, response, storage, disposal.

Code	Statement	Seen on
H272	May intensify fire; oxidizer	silver nitrate
H302	Harmful if swallowed	metol, hydroquinone, sodium sulfite (in some notifications)
H314	Causes severe skin burns and eye damage	sodium hydroxide, glacial acetic acid, silver nitrate
H315	Causes skin irritation	potassium bromide, potassium carbonate
H317	May cause an allergic skin reaction	metol, hydroquinone
H318	Causes serious eye damage	hydroquinone
H319	Causes serious eye irritation	sodium carbonate, potassium bromide
H400	Very toxic to aquatic life	silver nitrate, metol, hydroquinone
H410	Very toxic to aquatic life with long lasting effects	silver nitrate, metol

P statements are combined and recombined so freely that memorising them is pointless; two are worth recognising on sight.

P280 — Wear protective gloves / protective clothing / eye protection / face protection… — is the one whose slashes matter. The supplier deletes the options that do not apply. If your sheet says only “wear protective gloves”, that is a decision somebody made, not a truncation.

P305+P351+P338 — IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do — continue rinsing.

⚗A live example of why you re-read a sheet

GHS Rev. 11 changed the eye-splash response for the two most serious eye classifications. For H314 and H318 the statement now given is P305+P354+P338, IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing. The older P305+P351+P338 has not disappeared — it is still current for H319 — but the pairing changed, and PubChem’s list also marks P310, Immediately call a POISON CENTER or doctor, as obsolete. Nothing about the chemistry changed. The wording of the advice did, and a sheet printed in 2018 and a sheet printed this year will not read the same. That is what a revision date is for.

Classification moves with concentration

This is the part of GHS that beginners get wrong most often, and it is not a subtlety: the same substance in a different amount of water is a different classification.

The mechanism is that GHS classifies by category, and the categories have concentration boundaries. A mixture is classified from its ingredients and their concentrations, so a supplier who sells both a concentrate and a ready-to-use dilution publishes two different sheets with different pictograms on them. The clearest evidence is in the regulation itself: the harmonised European entry for acetic acid is titled “acetic acid … %”, with the percentage deliberately left open, because the entry carries different classifications at different strengths. Glacial acetic acid is Danger, H226 and H314. A working stop bath made from it is a dilute weak acid, and its supplier’s sheet will say what it is rather than what the concentrate was.

Three practical consequences.

• Do not carry a concentrate’s classification onto its dilution. It over-warns, and a warning nobody believes is worse than none, because the next one is not believed either.
• Do not carry a dilution’s classification back onto the concentrate. This is the dangerous direction, and it is what happens when somebody who has only ever handled working solutions opens a bottle of concentrate for the first time.
• Where you dilute something yourself, you own the resulting classification and you have no sheet for it. The honest label says what you made and from what — “stop bath, 2 % v/v from glacial acetic acid” — so that the reader can reason from the concentrate’s sheet rather than guess.

Identification: why a name is not enough

The identification chain, and where each link fails on its own

1. 1Common or trade name — fails: metol, Elon, Photol and Rhodol name one substance; "hypo" names two
2. 2Systematic name — fails: sulphite and sulfite are the same salt; ECHA files sodium sulfite under the British spelling
3. 3Molecular formula — fails: Na2S2O3 does not say whether the water of crystallisation is there
4. 4CAS registry number — holds: each substance and each hydrate has its own, and it is language-independent
5. 5Your own label — fails unless it adds the concentration and the date; a substance is not a solution

Every link is worth writing down. Only the fourth one settles an argument.

Here is the case the manifest asks for, resolved with real numbers.

What the bottle might say	Substance	Formula	Relative molecular mass	CAS
sodium sulphite	sodium sulfite, anhydrous	Na₂SO₃	126.05	7757-83-7
sodium sulfite anhydrous	sodium sulfite, anhydrous	Na₂SO₃	126.05	7757-83-7
sodium sulfate	sodium sulfate, anhydrous	Na₂SO₄	142.04	7757-82-6

The first two are the same substance under two spellings. British usage writes sulphite, the IUPAC spelling used throughout this course writes sulfite, and ECHA’s own record for the substance is filed as “Sodium sulphite” while PubChem titles it “Sodium Sulfite”. The third is a different compound with one more oxygen, and it is the thing your sulfite slowly turns into on the shelf, which is why it is exactly the wrong substance to confuse it with.

Then look at the CAS numbers. 7757-83-7 and 7757-82-6. They differ in one digit in the middle and one at the end, and the PubChem compound identifiers are 24437 and 24436 — adjacent. Two substances one letter apart in name are also next to each other in every registry, which is a warning rather than a convenience: the CAS number resolves the ambiguity only if you read all of it.

Hydrates, and what they do to the mass you weigh

Substance	Formula	Relative molecular mass	CAS
Sodium thiosulfate, anhydrous	Na₂S₂O₃	158.11	7772-98-7
Sodium thiosulfate pentahydrate (“hypo”)	Na₂S₂O₃·5H₂O	248.19	10102-17-7
Ammonium thiosulfate	(NH₄)₂S₂O₃	148.21	7783-18-8
Sodium carbonate, anhydrous	Na₂CO₃	105.99	497-19-8
Sodium carbonate monohydrate	Na₂CO₃·H₂O	124.00	5968-11-6
Sodium carbonate decahydrate	Na₂CO₃·10H₂O	286.14	6132-02-1

🧮A formula calls for 100 g of anhydrous sodium thiosulfate and you have the pentahydrate

The number of thiosulfate ions has to be the same, so the masses are in the ratio of the relative molecular masses:

mass of pentahydrate = 100 g × (248.19 / 158.11) = 100 × 1.5697 = 157 g

Both molar masses come from PubChem’s computed properties, and the arithmetic is one multiplication. Going the other way, 100 g of the pentahydrate is equivalent to 100 × (158.11 / 248.19) = 63.7 g of the anhydrous salt. The general treatment — including the trap that the extra 57 g is water that also counts towards your final volume — belongs to the concentration and dilution page later in this part. What belongs here is the identification: a formula that says “sodium thiosulfate” without saying which one has not told you what to weigh.

Sodium and ammonium thiosulfate are a different case again. They are not two forms of one substance; they are two salts with different cations, different masses, different fixing speeds and different classifications, and the course keeps them apart everywhere. A rapid fixer is ammonium.

Grades

“Reagent grade”, “analytical grade” and “laboratory grade” belong to supplier and pharmacopoeia specifications that state a purity and an impurity profile. “Photographic grade” does not. This course searched its corpus for a standard defining the term and found none, so it treats it as a supplier’s assurance that the material is suitable for photographic use and contains no impurity the supplier knows to be harmful in that use — which is worth something, and is not a specification. Where a formula in this course is sensitive to an impurity, the page says which impurity and why.

Where classifications come from, and why two sources disagree

A GHS classification on a bottle can have two quite different origins, and telling them apart is the single most useful piece of literacy on this page.

A harmonised classification is legally binding across a jurisdiction. In Europe these are set out in Annex VI of Regulation (EC) No 1272/2008, and PubChem shows them under that regulation’s name. Silver nitrate, metol, hydroquinone, sodium hydroxide and acetic acid all have one. Nobody gets to disagree with it.

A notified classification is what individual companies have told ECHA they use. ECHA publishes them in the C&L Inventory, and PubChem aggregates them, showing what percentage of notifications carry each statement. It is a survey, not a verdict.

The difference is not academic. Look at sodium sulfite, which has no harmonised entry:

Statement	Share of ECHA notifications
H314, causes severe skin burns and eye damage	51.8 %
H319, causes serious eye irritation	21 %
H315, causes skin irritation	19.3 %
H302, harmful if swallowed	18.3 %
does not meet GHS hazard criteria at all	24.9 % (618 of 2,482 reports)

Half the notifiers call sodium sulfite corrosive; a quarter say it is not classified at all. Those notifications cover different grades, concentrations and product forms, and the aggregate is the sum of many different products rather than a judgement about one. Contrast hydroquinone, where the harmonised entry and the notifications agree with every statement in the harmonised entry at above 99 per cent, and silver nitrate, where H314 appears in 99.9 per cent of 803 reports.

=How this course uses each

A harmonised classification is quoted as fact, with the regulation named. A notified aggregate is quoted as a survey, with the percentage attached, precisely so that a reader can see how much agreement is behind it. And neither replaces the sheet for the product you bought: an aggregate over 2,482 notifications tells you what the market thinks of a substance, and your supplier’s sheet tells you what is in your jar.

A cross-check that is not a substitute

PubChem and ECHA are excellent for a substance and useless for a product. Use them to check that a supplier’s sheet is not an outlier, to find a CAS number, and to look up a hazard statement’s text. Do not use them to decide how to handle the bottle on your bench, which may be a mixture, a solution, or a grade whose classification differs.

Two more sources are worth knowing. HSE’s EH40 lists the United Kingdom’s legally binding workplace exposure limits — acetic acid at 10 ppm long-term, hydroquinone at 0.5 mg m⁻³, silver soluble compounds at 0.01 mg m⁻³ — and a good section 8 will quote the limit for your jurisdiction. Note EH40’s own caution that its Carc, Sen and Sk annotations are not exhaustive: an unannotated entry is not a clearance.

One divergence a British reader will meet

Since 1 January 2021 chemicals placed on the Great Britain market have been regulated under the assimilated CLP Regulation as amended for Great Britain — GB CLP — with HSE, not ECHA, acting as the agency. Northern Ireland continues under EU CLP through the Northern Ireland Protocol and the Windsor Framework. In practice the classifications are largely the same, but the two lists are now maintained separately and can drift, so a British reader should treat an ECHA record as a cross-check rather than as the governing text for a product bought in Great Britain.

Finding the sheet

In order: the supplier you bought from, then the manufacturer, then a search on the exact product name. ILFORD publishes sheets for its photochemistry as sold, in eleven European languages with separate United States and Canadian versions; Kodak publishes an equivalent set. Both are free and neither requires an account.

If a supplier will not provide one, that is information about the supplier. This course could not verify from its corpus what, precisely, a United Kingdom supplier owes a private individual as distinct from a business, and does not guess. What it can say is that the obligation exists in the workplace regime — OSHA requires manufacturers and importers to provide a sheet with the initial shipment and with the first shipment after an update — that both major photographic manufacturers publish theirs openly to anyone, and that a supplier of hazardous chemicals who cannot produce a sheet on request has told you something you should act on.

Versioning: the six fields to record

Every substance you own gets a line, and the line is what makes a claim on a course page checkable against your actual material a year later.

1. Product name, exactly as printed on the container.
2. Supplier, and the manufacturer if they differ.
3. Document version or reference, from section 1 or the footer.
4. Revision date, from section 16.
5. The date you read it.
6. Where the file is, so the next person can find it. A dated PDF in a folder beats a link.

Re-check when you reorder from a different supplier, when a product’s packaging changes, and when a page in this course tells you a classification you did not expect.

Labelling what you fill

Kodak’s storage guidance says two things that sit in tension, and both are right. Store photographic processing chemicals only in the containers they were delivered in, and do not remove the labels that came on them. The first is the ideal; a decanted bottle is a bottle whose identity depends entirely on what you wrote. So when you do decant — and you will, because the accessibility route on the layout page depends on it — the label has to carry everything the original did, and more, because now there is a date and a dilution.

A label that works, and one that does not

1. 1Substance, in full — sodium sulfite, anhydrous — not "sulfite", not a trade abbreviation
2. 2Concentration, unambiguous — 10 % w/v — never a bare percentage
3. 3Date mixed — the clock on shelf life starts here
4. 4Date first opened — a second, faster clock; headspace and oxidation begin at this date
5. 5Hazard wording and signal word — copied from the supplier sheet for the material you used
6. 6Initials — so a question has somebody to go to, even in a household of one
7. 7Family — DEV, STOP, FIX, WASH or SILVER, in words as well as any colour code
8. 8The failure mode — an unlabelled or half-labelled bottle is not a chemical, it is waste

Write the label before you fill the bottle. A bottle filled first gets labelled 'in a minute'.

ILFORD’s leaflet for beginners gets to the same place in three sentences: do not store chemicals in soft-drink bottles, always label containers clearly, and store them safely and out of reach of children. The soft-drink rule is worth stating as its own principle, because it is the failure with the worst consequences: a container whose shape says “drink me” must never hold anything but a drink.

An unlabelled bottle cannot be used, because you cannot state what is in it; cannot be stored, because you cannot state what it must not stand beside; and cannot be disposed of as anything but an unknown, which is the most expensive waste there is. That is why this course treats an unlabelled bottle as waste rather than as a puzzle.

The chemical inventory

One sheet, one line per substance, updated when something arrives or is finished. The fields are the six versioning fields above, plus these:

Field	Why it is there
CAS number	the only field that survives a change of supplier, spelling or trade name
Hydrate or form	anhydrous, monohydrate, pentahydrate, solution at a stated strength
Quantity on hand	so that a formula can be checked against the shelf before a session, not during one
Container and size	because the storage page’s containment tray is sized from the largest one
Date opened	the clock that matters more than the date of purchase
Storage group	acid, alkali, oxidiser, developing agent, silver, thiosulfate — the next page defines these
Pages that use it	the column that pays

That last column earns its place the first time a later part specifies sodium metaborate tetrahydrate rather than the anhydrous salt: the inventory tells you in thirty seconds whether you have the right one, and the CAS column settles it if the label is ambiguous.

The fields are not arbitrary. They are, deliberately, the same fields this course’s own chemical encyclopaedia pages carry — identity, form, hazard data with a reference and a verification date, handling, storage, incompatibilities and waste — because those are the fields that make a chemical claim checkable by somebody who was not there when it was written. Your inventory and this course’s reference pages are the same document at two scales, and if you keep yours properly you can audit ours.

Recap

• A safety data sheet is about a supplied product at a supplied concentration. It never generalises to a substance, and this course never replaces it.
• Sixteen sections in a fixed order. Read 2, 4, 8 and 7 before opening a container; 10 before shelving it; 13 before it becomes waste; and record the version and revision date from 1 and 16.
• Nine pictograms, two signal words, H statements for what the hazard is and P statements for what to do. GHS Rev. 11 changed the eye-splash statement for H314 and H318 to P305+P354+P338 and marked P310 obsolete, which is the clearest possible argument for reading a current sheet.
• A name does not identify a substance. Sodium sulfite (CAS 7757-83-7) and sodium sulfate (CAS 7757-82-6) differ by one letter and one oxygen; sodium thiosulfate’s anhydrous and pentahydrate forms differ by 90 g per mole, which is a 57 per cent difference in the mass you weigh.
• A harmonised classification is binding; a notified aggregate is a survey. Sodium sulfite’s notifications split between H314 at 51.8 per cent and no classification at all at 24.9 per cent; hydroquinone’s agree with its harmonised entry above 99 per cent.
• “Photographic grade” has no standard behind it that this course could find.
• Every bottle you fill carries substance, concentration, both dates, hazard wording, initials and family. A bottle that carries less is waste.

Check your understanding

Question 1. Three bottles are labelled "sodium sulphite", "sodium sulfite anhydrous" and "sodium sulfate". Which two hold the same substance, and what settles it?

• The first two, settled by the CAS number 7757-83-7 on both
• The last two, because "anhydrous" and "sulfate" both mean the water has been removed
• The first and last, because sulphite and sulfate are alternative spellings
• None of them; all three are different substances

Show the answer and why

Answer: The first two, settled by the CAS number 7757-83-7 on both

Sulphite and sulfite are the British and IUPAC spellings of one anion, and ECHA files the substance under the first while PubChem titles it with the second; both resolve to CAS 7757-83-7, Na₂SO₃, relative molecular mass 126.05. Sodium sulfate is Na₂SO₄, CAS 7757-82-6, mass 142.04 - one more oxygen, and the substance your sulfite oxidises into on the shelf. "Anhydrous" is a statement about water of crystallisation and has nothing to do with the difference between a sulfite and a sulfate.

Question 2. A formula calls for 60 g of anhydrous sodium thiosulfate. You have the pentahydrate. What do you weigh?

• About 38 g
• 60 g; the water does not count
• About 94 g
• About 120 g

Show the answer and why

Answer: About 94 g

The relative molecular masses are 158.11 for the anhydrous salt and 248.19 for the pentahydrate, so the pentahydrate mass is 60 × 248.19 / 158.11 = 94.2 g. Weighing 60 g of the pentahydrate would give you only 38 g of thiosulfate, which is a third short. Note also that the extra 34 g is water, and it joins the water you add - which matters when the formula specifies a final volume rather than a volume of water, and is why the concentration page treats making up to a volume as a separate discipline.

Question 3. PubChem shows that 24.9 per cent of ECHA notifications say sodium sulfite does not meet GHS hazard criteria, while 51.8 per cent classify it H314, causes severe skin burns and eye damage. What is the correct conclusion?

• The majority view wins, so treat it as corrosive in all circumstances
• The classifications contradict each other, so neither can be relied on
• These are self-reported notifications covering many different products, grades and concentrations, so the aggregate is a survey; the sheet for your own material governs
• Sodium sulfite has a harmonised classification, so the notifications are irrelevant

Show the answer and why

Answer: These are self-reported notifications covering many different products, grades and concentrations, so the aggregate is a survey; the sheet for your own material governs

The C&L Inventory records what individual companies have notified for their own products, and a large split usually means the notifications cover materially different things - different concentrations, different grades, solutions against solids. Sodium sulfite has no harmonised entry, so no legally binding classification settles it. The spread is useful information: it tells you the substance sits near a classification boundary and that your supplier's sheet is the only document that describes what you actually bought.

Question 4. A safety data sheet printed in 2017 gives the eye-splash response as P305+P351+P338. Your new sheet for the same product gives P305+P354+P338. What changed?

• The product was reformulated to be more hazardous
• The supplier made an error in one of the two sheets
• The precautionary statement paired with the classification changed in a later GHS revision; the chemistry did not change
• P354 is a different kind of rinsing, using a specific irrigation solution

Show the answer and why

Answer: The precautionary statement paired with the classification changed in a later GHS revision; the chemistry did not change

GHS Rev. 11 pairs P305+P354+P338 - "Immediately rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing" - with H314 and H318, where the older pairing used P305+P351+P338, which says "rinse cautiously" and is still current for H319. The difference is one word of urgency in the advice, not a change in the substance. It is the clearest illustration on this page of why the revision date is one of the six fields you record.

Question 5. Why does this course refuse to treat "photographic grade" as a purity specification?

• Because photographic-grade chemicals are less pure than reagent grade
• Because the course searched its corpus and found no standard that defines the term, so it treats it as a supplier's assurance rather than a specification
• Because photographic grade is an obsolete term no supplier now uses
• Because purity is irrelevant to photographic results

Show the answer and why

Answer: Because the course searched its corpus and found no standard that defines the term, so it treats it as a supplier's assurance rather than a specification

Reagent, analytical and laboratory grades point at published specifications with stated purities and impurity profiles. No comparable standard for "photographic grade" turned up in this course's manufacturer, regulatory and reference corpus, so quoting one would be inventing it. That does not mean the term is worthless - a supplier selling to photographers has a strong interest in excluding impurities that fog an emulsion - but it means the phrase is a claim rather than a measurement, and pages sensitive to a particular impurity say which one and why.

Question 6. You decant a five-litre container of developer concentrate into five one-litre bottles so you can lift them. What has to be on each new label that was not needed on the original?

• Nothing; copying the original label is sufficient
• The date you decanted it and your initials, in addition to everything the original carried
• Only the hazard pictograms
• The supplier's address and emergency telephone number

Show the answer and why

Answer: The date you decanted it and your initials, in addition to everything the original carried

The original carried the substance, the concentration and the hazard wording, and all of that has to be copied. What the original could not carry is the history of your bottle: when this particular container was filled, and who filled it. Both matter, because shelf life runs from the date of decanting for the new bottles and from the date of opening for the concentrate, and because a question about a bottle needs somebody to ask. Kodak's ideal is that you do not decant at all and keep chemicals in their delivered containers; when accessibility or practicality overrides that, the label has to make up the difference.

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