You may occasionally have difficulty determining whether new signs or symptoms are due to a new workplace event or exposure or whether they are the continuation of an existing work-related injury or illness that has already been recorded. This is an important distinction, because a new injury or illness requires you to make a new entry on the OSHA 300 Log, while the continuation of an old recorded case requires, at most, an updating of the original entry.
Consider an injury or illness to be a "new case" if the employee:
Has not previously experienced a recorded injury or illness of the same type that affects the same part of the body, or
Previously experienced a recorded injury or illness of the same type that affected the same part of the body but had recovered completely (all signs and symptoms had disappeared) from the previous injury or illness and an event or exposure in the work environment caused the signs or symptoms to reappear.
The key to recording chronic illnesses is determining whether the conditions will progress even in the absence of workplace exposure or whether those conditions are triggered by events in the workplace.
In occupational illnesses where the signs or symptoms may recur or continue in the absence of an exposure in the workplace, the case must be recorded only once. Examples include occupational cancers, asbestosis, tuberculosis, byssinosis, and silicosis. These conditions are chronic — once the disease is contracted, it may never be cured or completely resolved.
However, when an employee experiences the signs or symptoms of an injury or illness that are the result of an event or exposure in the workplace, such as an episode of occupational asthma or contact dermatitis, you must treat the incident as a new case. It is typical, but not always the case, for individuals with these conditions to be symptom-free if exposure does not occur.
To help you determine if the case is new or recurring, you may, but are not required to, seek the advice of a physician or other licensed healthcare professional (HCP). However, if you do, you must follow the physician or HCP's recommendation about whether the case is a new case or a recurrence. If you receive recommendations from two or more physicians or HCPs, you must decide which recommendation is the best documented, best reasoned, and most authoritative and record the case based on that recommendation.