Occupational Exposure Limit (OEL) Validation of Isolators by Mr. Pravin Manker

The purpose of OEL validation is safety. Safety of humans, products and environment. Some products are extremely potent and pose threat to the people coming in contact with such products in micro doses over a sustained period of time.

The scope of OEL validation extends to areas of manufacturing operations, analysis, cleaning, effluent treatment, Research and Development and sampling and dispensing.

Risk impact analysis has been done when categorizing products into various OEL bands (OEB). Risk is directly proportional to the potency of the product, particle size, the scale of operation and the duration of exposure.

Safety Bands are categorized on the basis of free molecules of the potent substance in microgram per cubic metre (μg/M3). We have 6 bands from A to F. A being categorised at 10,000 μg/M3 to 1,000 μg/M3. F is categorised at 0.001 μg/M3 to <0.001 μg/M3. 

Key Features in OEL validation are:

1.  Operator’s risk of exposure

2.  Safety Band

3.  Limit of Detection (LoD)

4.  Limit of Quantitation (LoQ)

5.  Surrogate material

6.  Handling practices

7.  Sampling during OEL validation (air and/or swab)

8.  Handling the sample

9.  Recovery of sample

10. Method of Analysis

11. Analytical Method validation

12. Disposal

Route of exposure is inhalation of powders and aerosols and dermal contact of powders and solutions.

People likely to be affected are:

1.  R&D

2.  Warehouse (sampling and dispensing)

3.  Production

4.  Quality Control (samplers and analysers)

5.  Housekeeping

6.  Effluent treatment

7.  Maintenance (especially AHS)

8.  Others (employees and general public in case of leaks)

Validation Design is based on:

1.  Sampling equipment

2.  Measurement capability

3.  Sampling locations

4.  Sampling duration

5.  Validated Recovery

6.  Validated Analytical procedure

Surrogate material is preferred because if the risk of exposure exists, the surrogate material is not harmful to the exposed personnel.

OEL define the level to which a worker can be repeatedly exposed eight hours daily for forty hours weekly without experiencing adverse health effects due to exposure.