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Success Stories

Industrial Hygiene Success Story


Case 3: Exposure Control of Softwood Dust in Manufactured Home Facilities

Presented at the AIHC 2002 Poster Session by Chris Collins, former Georgia Tech Consultation Program Staff Member

Abstract

Inhalation of excessive levels of dust may cause nasal dryness, irritation, nasal obstruction, coughing, sneezing, wheezing, and nose bleeding. Other effects of inhalation may include bronchial asthma, sinusitis, prolonged colds, and respiratory problems. Skin and eye exposure may lead to allergic contact dermatitis and eye irritation. Additionally, wood dust has been classified as a carcinogen to humans by the International Agency for Research of Cancer (IARC).

This case study details an attempt to control over exposure to wood dust in a manufacturing home facility. Cabinet and Counter Makers operating table saws had ranges of wood dust exposure between 6.8-11.7 milligrams per cubic meter (mg/m3) respectively. The American Conference of Governmental Industrial Hygienist (ACGIH) has recommended a TLV of 5.0 mg/m3 for softwood dust and a TLV of 1.0 mg/m3 for hard wood dust.

An exhaust hood was placed on the table saws in accordance with NIOSH recommendations. The hood serves as both a guard and ventilation for the saw. Employee monitoring after the addition of the ventilation reduced employee exposure to 2.9- 4.4 mg/m3 respectively.

Background

The manufactured home facility is a privately owned company which has more than 300 employees. The facility operates 24 hours a day, 7 days per week. The shift is typically 8 hours but can vary depending on the days workload. In the Cabinet and Counter Top Area four employees on first shift cut wood for cabinet and counter top assembly. The majority of the 8 hour shift is spent cutting wood with a small portion of the shift (less than 1 hour) stacking wood and transporting to other areas for assembly.

The type of wood varied depending on the type of counter top or cabinet being made however all the wood types used during the survey were soft wood. Initial monitoring indicated that employees were overexposed to wood dust. Ventilation in accordance with NIOSH approved methods were installed and the employees were monitored again.

Methods

Wood Dust
Time weighted averages were taken from 3 employees. Samples were taken in accordance with NIOSH method 500 and 600. Samples were taken before and after ventilation was installed.

Evaluation Criteria
OSHA does not have a PEL specific for wood dust. However the ACGIH has recommended a TLV of 5.0 milligrams per cubic meter (mg/m3) for softwood dust and a TLV of 1.0 mg/m3 for hard wood dust.

Wood Dust
Inhalation of excessive levels of dust may cause:

  • Nasal dryness
  • Nasal obstruction
  • Coughing
  • Sneezing
  • Wheezing
  • Nose bleeding
  • Bronchial asthma
  • Sinusitis
  • Prolonged colds
  • Respiratory problems

Skin and eye exposure may lead to:

  • Allergic contact dermatitis
  • Eye irritation

Additionally, wood dust has been classified as a carcinogen to humans by the International Agency for Research of Cancer (IARC).

Results and Discussion

Before ventilation was installed all three employees monitored were above the ACGIH TLV for wood dust:

Name and Job Description Wood Dust (mg/m3)
Employee 1: Counter Builder 6.8
Employee 2: Cabinet Maker 8.7
Employee 3: Cabinet Maker 11. 0

After ventilation was installed all employee exposures dropped below the ACGIH TLV for wood dust:

Name and Job Description Wood Dust (mg/m3)
Employee 1: Counter Builder 3.1
Employee 2: Cabinet Maker 2.9
Employee 3: Cabinet Maker 4.4
Conclusions

The air sampling indicated that the addition of ventilation can serve both as a guard on the saw and as a simple and affordable method to help reduce employee exposure to wood dust.