legends · 3 min read ·
Safety Data Sheet
A chemical safety data sheet is revised four times as its additive teaches workers to understand a note.
**SAFETY DATA SHEET — Residuum-9 (industrial sealant additive)**
**Supplier:** Calder Chemical Ltd · **Revision:** 4 · **Date:** 3 March
**Section 1: Identification**
Product name: Residuum-9. Product use: additive for joint sealants, 0.5–2% by weight. Emergency telephone: on file.
**Section 2: Hazards**
Hazard class: Skin irritant, category 2. Eye irritant, category 2A.
Precautionary statements: Wear gloves and eye protection. Wash hands after handling.
**Section 4: First aid**
Eyes: rinse with water for 15 minutes. Skin: wash with soap and water. Swallowed: do not induce vomiting. Seek medical advice.
· · ·
**SAFETY DATA SHEET — Residuum-9 · Revision 5 · Date: 19 August**
**Section 2: Hazards**
Hazard class: Skin irritant, category 2. Eye irritant, category 2A. **Specific target organ toxicity, repeated exposure: category 1 (hearing).**
Hazard statement: *May cause persistent tinnitus following repeated skin contact.*
*Revision note: updated following reports from the works.*
· · ·
**Incident report (Calder Chemical, Unit 4 mixing hall, 11 August)**
Operator: S. Okoro. Task: transfer of Residuum-9 from drum to mixer, manual pour. Exposure: hands, forearms, low (gloves worn).
Operator reported a high steady note in the left ear starting about an hour after the pour. It continued through the shift. By the end of the shift she described the note as "a voice that has stopped halfway through a word."
First aid applied. Operator sent home.
· · ·
**Incident report (Calder Chemical, 29 August)**
Four operators in the mixing hall now report the same effect. All four describe the sound as a held note. All four describe it as getting more complex: a held note with a second note beneath it, then a third. By the second week the tone has an edge, a shape, like a word with the consonants taken out.
Operator Okoro asked to be moved to the packing line. She said she could now hear the note when she stood near the drums, even with her hearing protection on. She said the note was louder when the drum was full.
· · ·
**Occupational health memo (Calder Chemical, 12 September)**
To: Site Manager
Re: Residuum-9
1. Audiometry results for the four exposed operators are normal. Hearing thresholds are unchanged.
2. The operators report no tinnitus when they are in the audiometry booth.
3. The operators report the sound resumes in the corridor, between the booth and the mixing hall, and grows louder as they near the drums.
4. Operator Okoro asked me to note that she can now tell the direction of the sound. She says it comes from the empty drum store, the one that was bricked up in 2019.
Recommendation: reduce exposure. Rotate staff. Consider ceasing manual transfer.
· · ·
**Safety data sheet — Residuum-9 · Revision 6 · 14 October**
**Section 2: Hazards**
Hazard class: Skin irritant, category 2. Eye irritant, category 2A. Specific target organ toxicity: category 1 (hearing, speech).
Hazard statements: *May cause persistent tinnitus. May cause the sufferer to understand what is being said.*
Precautionary statements: Do not breathe vapours. Do not listen to the note. Do not repeat what is said.
**Section 4: First aid**
Swallowed: do not induce vomiting. Seek medical advice.
Hearing: remove from exposure. Move to a quiet place. *Do not answer.*
· · ·
**Incident report (Calder Chemical, 30 October)**
Mixing hall closed. All remaining stock of Residuum-9 (31 drums) quarantined and sealed. Operators sent for specialist assessment.
Operator Okoro attended the assessment and reported to the consultant that she has understood the voice for the last week. She would not say what it had said. She said it was not a threat. She said it was giving her instructions, very simple ones, in a calm and reasonable tone, and that she had already carried out three of them.
The consultant asked what the instructions were. She said: "I'll write them on the form."
· · ·
**Safety data sheet — Residuum-9 · Revision 7 · 31 October**
**Section 4: First aid**
Eyes: rinse with water for 15 minutes. Skin: wash with soap and water. Hearing: remove from exposure. Swallowed: do not induce vomiting. It will leave on its own.