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Personal breathing zone exposure monitoring and surface contamination study of Lead at an

indoor firing range

Prasanth.K, Deputy Project Manager, India

International Safety Systems, Inc. (ISS), India

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AGENDA

Background on indoor firing range

Test Environment and Activity

Methods and Evaluation criteria

Results and Observations

Lessons Learned

Recommendations

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Background

Indoor firing ranges used for

Shooting practice (Person inside firing range)

Testing Kevlar material (Person can be outside)

Potential Hazards (Noise and Lead)

Bullets are loaded with gunpowder and have Lead based primer.

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Lead vaporized due to heat and pressure within the cartridge (at the firing instance). The heat of the reaction and cooling results in formation of lead particles at Source

Bullet trap

Path way

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Test Environment and Activity

Indoor firing range had: Heating and Ventilated Air Circulation (HVAC) system

(2 supply ducts from top and 4 return ducts from side walls) with 20 air changes per hour

Acoustic enclosure Bullet traps

Operator places Kevlar material at test stand and loads the barrel with bullet and trigger is pulled from outside the room.

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Operator used apron and single pair of Nitrile gloves

Test centre cleaned daily with dry mop followed by wet mop.

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Objective of study

To identify eight-hour/full shift personal breathing zone exposure to lead particulates for operator testing the kevlar by firing bullets in an Indoor firing range.

To evaluate the level of surface contamination due to the deposition of lead particulates.

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Method and Sampling Strategy

Air sampling Three samples collected using Modified NIOSH 7300;

Inductively Coupled Argon Plasma-Atomic Emission Spectrometry (ICP-AES)

Sampling media: 37mm Matched Weight (MW) Mixed Cellulose Ester (MCE) filter

Sampling flow rate: 4 litres/minute Sampling duration: 7 hours. (Not sampled during lunch

break) Two filters used for 3.5 hours each to avoid overloading

of particulates on filter.

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Wipe sampling Modified NIOSH 9102 (ICP-AES) Sampling media: Moistened Lead Dust sampling wipe Wipe samples collected before start of the activity

(beginning of shift) after completion of activity (end of shift)

Wipe samples collected at 11 locations over an area of 100 cm2

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Evaluation Criteria

Air samples Eight-Hour Time Weighted Average (TWA) exposure

compared with ACGIH TLV-TWA of 0.05 mg/m3 (50 μg/m3)

Wipe samples OSHA guideline for a level of acceptable lead loading

for non-lead work areas of 0.2 μg/cm2. (Legally not applicable).

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Results and observations

Range of Personal Breathing Zone exposure – 1.0 µg/m3 to 1.7 µg/m3

Exposure varies: Based on the number of bullets fired. Duration of person inside the firing range.

Wipe samples results at beginning of shift - 0.02 µg/cm2 to 4.1 µg/cm2

Wipe samples results at end of shift – 0.13 µg/cm2 to 38 µg/cm2

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Lessons Learnt

Employee exposure, without regard to use of respirator was below 10% of ACGIH TLV-TWA.

The surface contamination level increased by 10 folds, after firing of bullets.

Potential for ingestion risk exists due to surface contamination.

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Recommendations

Clean all surfaces effectively with the use of a High Efficiency Particulate Air (HEPA) filter vacuum cleaner.

Use dual pair of disposable nitrile gloves before contacting potential contaminated surfaces. Remove the outer pair of gloves after it is contaminated.

Avoid touching of door handles with contaminated gloves

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References

• Indoor Firing Ranges Industrial Hygiene Technical Guide (Navy Environmental Health Center)

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Thank You!

Any questions ? Prasanth K. Prasanth.k@issehs.com

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