When a working life spans several employers, an occupational illness enquiry needs more than a list of company names. It needs a fair account of what happened during each period, which hazards may have been present, how conditions changed and what evidence supports the account. The longest job is not automatically the most important. The most memorable workplace is not necessarily the only relevant one. A useful history allows those questions to be examined rather than answered by assumption.
This guide is for enquiries governed by the law of England and Wales. Its practical task is building a multi-employer exposure matrix: a table that keeps employment identity, tasks, hazards, dates and sources together. It does not diagnose a condition or tell a reader how to divide legal responsibility. Different diseases raise different causation questions, and some have special rules. A medical diagnosis and a list of employers alone cannot determine the correct defendants or their shares of any liability.
If a possible connection between illness and work has been raised, seek advice promptly while preparing the matrix. Do not wait until every former colleague or insurer has been found. The industrial disease claims service provides the wider context for an enquiry. The evidence method below helps you explain a complicated work history clearly enough for the next decisions to be made.
Exposure periods
Make each row represent a stable period of work
Start a new row whenever the employer, site, main task or relevant control measures changed materially. One employment contract may therefore produce several rows. Conversely, repeated short assignments at the same site may need separate rows because the work differed. The objective is to avoid treating a whole career as a single exposure while keeping the table manageable enough to use.
For each period, record the employer name shown on documents, any trading name, the workplace address and your job title. Add what you actually did. “Maintenance technician” could mean office planning, workshop repairs or entering production areas during shutdowns. A short task description explains which records and witnesses may matter. The legal employer and the business controlling the premises should have separate fields when they are different.
Dates should be as precise as the evidence permits. Use exact dates when supported, month-and-year estimates when appropriate and broader ranges when memory is weaker. State why you chose the range. Do not turn an approximate five-year period into an exact start and finish date merely because a spreadsheet requires a value. A notes column can preserve the uncertainty until better records arrive.
Include overlapping and interrupted work
Some workers hold a weekday job and a weekend job, move between agencies or return to a trade after several years away. Record overlapping periods openly. Do not force every job into a non-overlapping sequence just to make the page look neat. Add typical days or hours for each role so an adviser can understand how the periods fit together without counting the same hours twice.
Include absences that materially affected the work pattern. Extended sickness, maternity leave, military service, overseas assignments and lengthy unemployment may all help establish when exposure did or did not occur. Ordinary annual leave need not become a diary of every holiday unless the expert requests that detail. The initial task is to identify substantial differences, not to manufacture a false level of precision across decades.
If you were self-employed for part of the period, label it accurately. Who engaged you, who supplied equipment and who directed work may become relevant, but status should not be resolved from a convenient label alone. Preserve contracts, invoices and payment records. A period outside employed work may still matter to the medical exposure history even where the legal route differs from an employer's liability claim.
Use employment documents for what they can establish
Tax, pension and payroll documents can anchor company names and dates. They rarely prove how dusty a task was or whether a particular tool ran for two hours a day. The HMRC employment history guidance explains how records can be requested, including for compensation claims. Compare those records with your own papers rather than expecting one source to answer every question.
Create a source reference for each important entry. A row might cite “P60 for 1998”, “union card”, “recollection of workshop move” or “former supervisor, overlap 1994–1997”. Different sources provide different strengths of support. A contemporary document may establish a date while a witness supplies task detail. Combining them carefully is more useful than assigning every row the general label “confirmed”.
When records disagree, add a discrepancy note. Perhaps a payroll company name changed while the trading name remained the same, or a contract continued after actual work stopped. Avoid silently selecting the version that produces the longest period of exposure. An adviser needs to see the conflict in order to resolve it and consider whether it affects identity, duration or both.
Different hazards
Keep the hazard description specific
Separate noise, vibration, dust, fumes, chemicals and other possible hazards into distinct fields or linked notes. They are not interchangeable merely because they occurred in the same workshop. A process can involve one hazard during operation and another during cleaning. Record what you observed and what you know from documents, leaving uncertain material identities visibly unresolved.
For dust, describe the material being cut, mixed, removed or swept, the method and the surrounding work. HSE's construction dust guidance distinguishes the health concerns associated with common construction processes. That guidance can help frame questions, but a visible cloud does not identify its composition or establish a personal dose. Historical product information and expert interpretation may still be needed.
For noise, identify sources, proximity, how many operated together and how work was divided through the day. For hand-arm vibration, identify equipment and actual operating contact time, rather than equating a shift with continuous tool use. For skin or respiratory sensitisation concerns, product names, task changes and symptom patterns may be relevant. Let the clinician decide which details have diagnostic significance.
The vibration tools and working-pattern guide helps develop the tool-use entry into a task-specific record. Keep that detail linked to the relevant employer and period, so a later change of tool, maintenance regime or operating pattern is not applied retrospectively to the entire work history.
Record controls in the same period as the hazard
A statement that “masks were provided” is incomplete without dates, type, task and actual use. A statement that “there was no protection” may also be inaccurate if engineering controls existed. Record extraction, enclosure, wet working, quieter equipment, job rotation, training and personal protective equipment separately. Note the source of each recollection and any significant changes over time.
An employer may have introduced a control halfway through your employment. Split the row at that point if the change matters to exposure reconstruction. Do not assume that an installation date proves consistent operation. Maintenance logs, replacement filters, fit-testing records, training records and witness accounts may help establish how a measure functioned in practice. Equally, do not infer failure solely because disease later developed.
Your personal use should be described candidly. If protection was uncomfortable, unavailable on some shifts or incompatible with another item, explain the circumstances. If you sometimes chose not to use it, tell the adviser. The legal significance depends on the wider evidence and should not be guessed. An account that omits these facts may distort both the exposure assessment and advice about responsibility.
Do not merge unrelated illnesses into one explanation
A person can have more than one condition and more than one possible cause. Keep diagnoses, suspected diagnoses and symptoms distinct. Hearing difficulty does not prove a noise-related diagnosis; hand symptoms do not establish vibration injury; breathlessness does not identify a particular dust disease. A matrix is an evidence tool, not a medical decision system. Link each possible hazard to the relevant clinical question without assuming the answer.
Where two conditions are being investigated, it may be useful to maintain one employment chronology with separate hazard sheets. That avoids recreating the same dates inconsistently while allowing the evidence needs to differ. The hearing sheet may focus on noise surveys and audiograms. The respiratory sheet may focus on substances, ventilation and chest investigations. Each should clearly identify the source records it relies on.
For construction work, the focused guide construction dust exposure: records worth preserving can help develop the dust rows. Use it to deepen the relevant evidence, rather than adding every possible hazard to every employer. A shorter, well-supported account of the actual work is more useful than a comprehensive-looking list of substances copied from an industry description.
Relative contribution
Exposure duration is only one variable
Two periods of the same length can involve very different work. One might involve occasional contact with a process while another involves frequent close work with few controls. Intensity, frequency, task, material and protective measures can all require assessment. A claimant should therefore resist dividing responsibility by years of employment before an expert has considered what those years involved.
A matrix can record a relative description such as “monthly maintenance task” or “main production duty”, provided it states the underlying facts. Avoid unsupported percentages such as “Employer A caused seventy per cent”. Even a numerical estimate of dose requires suitable inputs and an appropriate method. Legal responsibility adds further questions about duty, breach, causation and the particular disease that arithmetic alone cannot answer.
Do not exclude an employer because another appears to have involved heavier exposure. The lesser period may still need investigation, or it may prove irrelevant once the evidence is examined. Equally, inclusion in the matrix is not an allegation that every employer acted unlawfully. Label the document as a history for assessment, and reserve legal conclusions for the advice and evidence that follow.
Distinguish medical causation from legal allocation
Medical experts may consider whether occupational exposure contributed to a condition, what alternative explanations exist and whether the effects can be divided. Lawyers must then apply the relevant legal tests to the evidence. Those are connected but different tasks. A clinical view that work was relevant does not automatically identify a negligent employer, while evidence of poor conditions does not automatically establish that those conditions caused the diagnosed illness.
Some occupational disease cases concern cumulative injury that can potentially be apportioned; others involve different causation principles. Mesothelioma has a particular statutory framework under section 3 of the Compensation Act 2006. It would be wrong to transfer that framework to every asbestos-related condition, every lung disease or every case involving several employers. The diagnosis and legal basis must be established before conclusions are drawn about recovery.
The dedicated guide after an asbestos-related diagnosis addresses the next evidence questions in that setting. Tell your adviser the exact diagnosis recorded by the clinician rather than simply saying “asbestos illness”. Different terms can refer to materially different conditions. If the wording is unclear, provide the letter and ask the treating team for clarification through the normal clinical route.
Keep non-work sources in the same factual picture
Include relevant home renovation, hobbies, military service and environmental exposure in a separate section. State dates and activities without deciding their causal importance. This helps prevent a misleading comparison that treats the known employers as the only possible sources. Medical records may also contain relevant smoking history, prior disease or treatment. Such information should be accurate and consistent across the accounts given to advisers and clinicians.
The purpose is not to dilute a legitimate concern about work. It is to make the investigation reliable. If a non-work task was brief, describe it as brief and explain the basis. If it was regular, do not reduce it to an isolated event. An expert can only evaluate competing explanations sensibly when the history reflects the actual pattern rather than a preferred legal theory.
You need not solve difficult scientific questions yourself. Write the factual question clearly: “Could this weekly task matter alongside the factory work?” or “Does this diagnosis distinguish between these substances?” A well-framed question helps the solicitor decide what expertise to obtain. It also reduces unnecessary effort collecting material that does not address the disputed issue.
Records and witnesses
Build an evidence map beside the matrix
For each row, identify the best available record and the most useful missing record. Existing documents might include training certificates, photographs, site diaries, work orders, purchase records, risk assessments or occupational health correspondence. Missing material might be a noise survey, extraction maintenance history or the specification of a product used during a particular contract. Explain why each requested item could matter.
Requests should be proportionate and directed to a relevant custodian. A solicitor can help identify what can properly be requested from an employer, insurer or other organisation. Do not take confidential records from a former colleague's account or access a workplace system without authority. Preserve documents you lawfully hold, including their dates and context, and explain how you obtained them.
A photograph can establish layout, machinery or work practices, but its limits matter. Identify when and where it was taken, who supplied it and whether it shows an ordinary day or a staged event. A promotional photograph may show a tidy area after a refit. A single image cannot establish a whole decade of conditions, although it may point to a useful change or line of enquiry.
Ask witnesses about their own overlap
A colleague can usually speak most directly about the years, area and tasks they shared with you. Record that overlap. Someone who joined after you left may help identify corporate history but cannot ordinarily confirm your daily working conditions from personal observation. Distinguish what they saw from what other workers later told them. Both may provide leads, but they are not equivalent evidence.
Avoid sending witnesses a completed matrix for collective approval. First ask open questions about their role, the work process and changes they remember. If documents are later shown to them, record which documents and whether these refreshed or changed their recollection. Independent accounts may differ in good faith. Do not pressure a witness to remove a difference merely to produce a uniform story.
When several witnesses cover different employers, use a separate contact list with their consent and relevant periods. Keep personal contact details out of any broadly shared working document. A public appeal for former colleagues should be carefully considered with the adviser, especially where health details or allegations would be disclosed. A targeted, factual enquiry may achieve the purpose with less unnecessary exposure of personal information.
Multi-employer exposure matrix
The following structure is designed for copying into a document or spreadsheet. Give each row an identifier such as E1 or E2. Use that identifier on supporting notes and attachments. The same employer can appear in several rows where duties or controls changed, and each row can link to more than one hazard sheet.
| Column | Entry to make | Decision it helps inform |
|---|---|---|
| Row and period | Dates, confidence level and basis | Which periods require verification |
| Legal employer | Documented name, company number if known, trading name | Which entity requires investigation |
| Workplace and role | Address, department and actual tasks | Where relevant records and witnesses may exist |
| Hazard or product | Known identity or careful description | Which technical or medical questions arise |
| Work pattern | Frequency, duration, proximity and variation | Whether an exposure estimate is possible |
| Controls | Measures, dates, use and reported problems | What conditions applied during that period |
| Evidence held | Document references and witness overlap | What presently supports the account |
| Evidence gap | Specific missing fact and possible source | What to request next |
| Health link | Relevant symptom or clinical event, without causal conclusion | Which medical records should be reviewed |
A row should remain readable. Put lengthy descriptions in a linked note rather than squeezing them into a tiny cell. The matrix is an index to the evidence, not a substitute for a full statement. An adviser should be able to scan it and identify the main employers, periods and uncertainties before reading the detailed account.
Add a separate revision log. If a P45 changes a leaving date or a colleague identifies the correct workshop, record the date of the amendment and the reason. Keep the earlier version. This is especially useful where one correction affects several rows, such as discovering that a group reorganisation changed the employing entity while the site and tasks remained the same.
Hypothetical example: three employers and different tasks
Imagine a worker with a respiratory diagnosis who spent four years cutting stone, twelve years in a general warehouse and two years on demolition projects. The first draft simply labels all eighteen years “dust exposure”. The matrix replaces that label with specific tasks. The stone period identifies cutting methods and workshop arrangements. The warehouse period records occasional damaged-bag cleanup. The demolition period identifies sites and materials that remain uncertain.
A payroll record confirms the stone employer. A warehouse colleague recalls that cleanup duties changed after a new contractor was appointed. The demolition agency's name differs from the contractor shown on site passes. These findings create different enquiries: historic process evidence, the timing of a task change and the relationship between the agency and site businesses. None permits the worker to allocate legal responsibility by years alone.
The worker also records a home renovation project and an earlier respiratory consultation. The adviser can now ask appropriate questions about diagnosis, exposure reconstruction, limitation and potential defendants. The example does not imply that any claim would succeed. Its purpose is to show how specific rows turn a broad suspicion into an investigation that can be tested and refined.
Hypothetical example: the same factory under different names
Consider a machinist who worked in one building for twenty years while the sign outside changed twice. They remember no break in employment and assume there was one employer. Wage records instead show two companies, and a later letter mentions a transfer. The matrix keeps the site constant but separates the legal names and the dates supported by documents. It also records a move between departments that changed the machinery nearby.
This distinction matters because corporate identity, workplace conditions and insurance history are separate questions. A later owner may hold useful archives without being the correct defendant for every earlier period. A policy under a group name may require further investigation. By preserving those distinctions, the worker avoids directing the whole enquiry to whichever company currently answers the telephone at the site.
Turning the matrix into practical decisions
Identify the first three unresolved questions
Once the table is drafted, choose the gaps most likely to affect the enquiry. One may concern the actual employing company. Another may concern the substance used in a process. A third may concern an earlier medical discussion about work. Prioritise those before spending time on minor details that cannot change the immediate decision. A solicitor can help assess which gaps are legally significant.
A useful question is narrow enough to answer. “Find everything about the factory” is difficult to action. “Identify the extraction system used in the grinding bay between the move and the 1996 refit” points to particular witnesses and documents. The more precise question also makes a negative response informative: it becomes possible to see what was searched and what remains unknown.
Set a review point after receiving the first records. New evidence may make an entire line of enquiry unnecessary or reveal a different employer. Do not keep repeating searches with the same assumptions if the evidence changes. Update the matrix, explain the change and ask whether the investigation should now focus elsewhere. The working document should develop with the evidence rather than defend its first version.
Keep time limits separate from completeness
A complex work history can take time to reconstruct, but that does not pause a legal deadline. In England and Wales, personal injury limitation can depend on the injury and a later legally defined date of knowledge, with exceptions and possible discretion. The Limitation Act 1980 requires individual analysis. The date an insurer is found or a matrix is completed does not automatically start a new period.
Tell the adviser about earlier screening, consultations, workplace warnings, benefit applications and previous legal enquiries. These may matter to timing even if the current diagnosis is recent. If you are retired, the guide occupational illness diagnosed after retirement explains how to separate employment events from medical knowledge. A partially completed matrix is sufficient to begin an urgent conversation.
If some employment occurred outside England and Wales, identify it immediately. Another jurisdiction may have different rules or affect where a claim can be brought. Do not assume one uniform deadline applies across a career involving overseas work, Scotland or Northern Ireland. The matrix should expose those periods rather than absorb them into a general “UK employment” entry.
Test the matrix for accidental duplication
Check entries that involve the same site under more than one employer name. A corporate name change may create two labels for one period, while a genuine employment transfer may require distinct periods. Do not count both as additional years of work until the relationship is clarified. The matrix should show the ambiguity and the supporting documents rather than resolve it through duplicate rows that inflate the chronology.
Review tasks occurring at the same time. If you used a tool beside another process, two hazards may have been present concurrently, but the hours are not necessarily consecutive. State the overlap in words. This matters particularly when different experts use the same work history for different questions. The noise specialist and the respiratory specialist may need separate exposure assessments while relying on one consistent account of your day.
Finally, check that a witness has not been attributed to periods before they joined or after they left. A person may know the business history through later conversations, but that is different from observing your work. Mark the boundary of their direct knowledge. These checks improve the matrix without requiring you to decide which employer is legally responsible or which exposure caused the illness.
Prepare the handover to an adviser
Provide a short covering note stating the diagnosis or investigation, the main potential exposures, any urgent issue and the key uncertainty. Attach the matrix, a document index and selected important records through an agreed secure channel. Keep original documents safely. Tell the adviser which witnesses are available and whether any have health or age-related circumstances that make early contact important.
Ask what additional evidence is necessary before substantial cost is incurred. The answer may involve medical records, technical expertise, corporate searches or insurance enquiries. Clarify the scope and cost of each proposed stage. AJ Solicitors operates on a private-fee basis and does not offer legal aid; this article does not offer a conditional fee arrangement or promise that the firm will accept a particular matter.
A good handover makes uncertainty manageable. It should show what is known, what is remembered, what is disputed and what still needs checking. That allows a considered decision about further investigation, including the possibility that evidence does not support a claim. The value of the matrix is that it helps reach that decision on a clear factual foundation.
Frequently asked questions
1. Must I identify the employer responsible before seeking advice?
No. Identifying the correct parties is part of the investigation. Provide the names, sites, dates and tasks you know, with copies of documents that may establish the legal employer. Avoid selecting one company simply because it is still trading. An adviser can assess which entities require further enquiries and whether other businesses involved in the work may also be relevant.
2. Is the employer I worked for longest usually the main one?
Length of employment is only one part of the picture. Tasks, intensity, frequency, materials and controls may differ substantially between workplaces. A long period in a lower-exposure role may raise different questions from a shorter period involving another process. Record the underlying facts and allow appropriate experts and legal advisers to consider their significance for the particular diagnosed condition.
3. Should I divide responsibility according to years worked?
Do not assign percentages yourself. A time-based division may ignore important differences in exposure and may not fit the legal rules for the disease concerned. Your matrix should describe periods and conditions, not calculate a settlement allocation. If an expert later proposes an approach to apportionment, the factual inputs and legal basis can then be examined with the adviser.
4. What if one employer has closed and another is still trading?
Include both periods accurately. Closure can affect tracing and procedure, but it does not justify deleting potentially relevant exposure from the medical history. The adviser may investigate historic insurance and corporate records. The fact that one company is easier to contact does not establish that it should answer for all the effects of work carried out elsewhere.
5. How should agency assignments appear in the matrix?
Record the agency, the business where you worked, the site and the dates separately. Add who paid you, who assigned daily tasks and who supplied equipment, if known. Preserve contracts and assignment records. Those facts help an adviser investigate the relationships without assuming that the name on a site badge or wage slip answers every question about legal responsibility.
6. How do I map brief maintenance visits to customer sites?
Use a linked visit schedule showing the customer premises, equipment serviced, task and approximate duration. Job sheets, mileage records and invoices may support the dates, but distinguish travel time from time spent near the hazard. Where visits were numerous, explain the basis of any grouping and identify unusual shutdown work separately. Record whether you attended as an employee, subcontractor or self-employed engineer without assuming that the customer's premises alone determine responsibility. This preserves short exposures that a list of permanent workplaces could miss.
7. Can I use one row for an employer where I held several roles?
You can use one summary row, but materially different tasks should have separate linked periods or notes. A move from production to an office can change the exposure picture even if the payroll name stays the same. Splitting the period makes it easier to compare work patterns, controls and witnesses without implying that every year involved the same conditions.
8. What if I cannot identify a product or chemical?
Describe what you know: its use, packaging, colour, supplier if remembered and the period involved. Mark the identity as unconfirmed. Purchasing records, technical sheets or colleagues may help later. Avoid copying the name of a hazardous substance from a similar industry example and presenting it as fact. Accurate uncertainty is more useful than an unsupported technical label.
9. Are dusty photographs enough to prove harmful exposure?
A photograph may show conditions, equipment or layout, but it has limits. Its date, location and context need to be established, and visible dust does not by itself identify composition or dose. Preserve the original image and explain its source. An adviser or expert can consider it alongside task accounts, records and witnesses rather than treating it as complete proof.
10. Should witnesses compare their memories before giving accounts?
Independent accounts are generally more informative. Witnesses can identify their own tasks and periods without agreeing a common narrative first. Differences may reflect different shifts, locations or honest uncertainty. Record those differences and let the adviser investigate them. A jointly polished account can obscure the source of a recollection and make it harder to assess what each person actually observed.
11. Does mesothelioma follow the same rules as hearing loss?
No. Different conditions can raise different causation and allocation questions, and mesothelioma has a specific statutory framework. Do not apply a rule encountered in one disease claim to another. Give the adviser the exact clinical diagnosis and complete exposure history so the appropriate legal approach can be considered rather than relying on a general rule about multiple employers.
12. Do I need measurements from every workplace?
Historic measurements can be useful, but they may not exist or may not match your task and period. Preserve any available surveys with their dates and methods. Detailed factual descriptions and other evidence may help an expert assess what can reasonably be reconstructed. Do not invent readings or use a modern measurement as if it directly established conditions decades earlier.
13. What should I do if two records give different leaving dates?
Keep both and note the discrepancy. One date may reflect the last day worked and another the administrative end of employment, or there may be a different explanation. Do not silently choose the date that lengthens exposure. Identify the source of each date so an adviser can decide whether further evidence is needed and whether the difference matters.
14. Should an overseas job be included even if I now live in England?
Yes. It may be important to the medical history and may introduce separate legal questions. Record the country, employer, site and dates, together with any contract documents. Residence in England now does not make every earlier job subject to identical rules. An adviser can identify whether another jurisdiction or specialist input needs to be considered.
15. Can a matrix replace a witness statement?
Usually it is a preparation and reference tool, not a complete substitute for formal evidence. A statement may need a fuller explanation of what you personally remember and how documents support it. The matrix helps organise that process and reveal gaps. Keep the distinction clear so short entries are not mistaken for a complete or legally settled account.
16. What if I had two jobs during the same years?
Show the overlap and describe the usual schedule for each. This avoids counting the same hours twice or forcing an inaccurate sequence. Explain any variation, such as seasonal weekend work. The exposure assessment may need to consider both patterns together, but the employment identities and sources should remain separate so the facts can be examined properly.
17. Should I include periods where protection was good?
Yes. The history must reflect changes and effective measures as well as concerns. A period with better controls may be important when assessing exposure, symptom development or differences between employers. Omitting it can distort the account. Describe what the controls were, when they were used and the evidence supporting your recollection without deciding their final legal effect.
18. Is a previous benefit application relevant?
It may contain employment details, medical information or an earlier statement about a work connection. Give the adviser a copy, including the outcome, even if the application was unsuccessful. Benefits and civil claims use different tests, so neither success nor refusal automatically settles liability. The earlier account can nevertheless help identify records, inconsistencies and dates requiring attention.
19. How should I prioritise missing evidence?
Focus first on gaps that could change an immediate decision: employer identity, a potentially important exposure, an earlier medical warning or a time-sensitive witness. Explain why each missing item matters and who might hold it. The adviser can help sequence requests so that cost and effort are directed towards significant questions rather than collecting a large but unfocused archive.
20. What should the final matrix make clear?
It should distinguish documented facts, personal recollection, witness evidence and unresolved assumptions. A reader should be able to see the employment sequence, changing tasks, possible hazards and the source of each important entry. It need not prove a claim. Its purpose is to support informed decisions about further evidence, suitable experts, potential defendants and the practical next steps.
