Transcript Occupational Exposure to Silica

Silica
Special Emphasis Program
 OSHA’s
Industrial Hygiene initiative
 Collaboration of OSHA Compliance
and Consultation Programs
Why Target Crystalline Silica
Exposure?
 Widespread
occurrence and use
 Number of related deaths
 Number of exposed workers
 Health effects
Occurrence and Use
 SiO2
- basic component of sand,
quartz & granite
 Quartz - 2nd most common mineral
in the earth’s crust
 Airborne silica is produced by:
Industries
 electronics
 railroad
 foundries
 slate
and flint
quarrying and
 ceramics, clay,
pottery, stone, and crushing
glass
 use and manufacture
of abrasives
 construction
 mining
 agriculture
 maritime
Occurrence and Use
 Airborne
silica is
produced by:
–
–
–
–
–
–
sandblasting
rock drilling
foundry work
stone cutting
drilling
quarrying
– tunneling jack
hammering
– concrete manufacturing
– demolition
– asphalt pavement
manufacturing
General Industry Targeting
 Focused
to particular establishments
where overexposures to crystalline
silica are most likely or known.
 Records review
– Silicosis diagnosis may include:
pneumoconiosis, fibrosis, respiratory
disease, non- malignant respiratory disease,
congenital heart failure
Permissible Exposure Limit
(PEL)
10 mg/m3
= ? mg/m3
% Quartz +2
PEL for respirable dust
containing a % silica.
Respiratory Protection
up to 0.25mg/m3
up to 0.50 mg/m3


PAPR, SAR

up to 1.25 mg/m3
up to 2.5 mg/m3


up to 50 mg/m3

APR w/HEPA, tightPAPR w/HEPA, full face
SAR or SCBA
SAR pressure demand




dust respirator
dust/mist,SAR, SCBA,
no single use or quarter
mask
Silicosis Prevention Program

Medical surveillance program
– baseline examination
medical and occupational history
prior to exposure
– every 5 years if < 20 years of exposure
– every 2 years if > 20 years of exposure
– baseline chest x-ray
– pulmonary function tests (PFT)
– x-ray upon termination of employment
Source: OSHA SEP
Silicosis Prevention Program
 Personal
air monitoring program
 Training and information on crystalline
silica
 Availability of air and medical
surveillance data to workers
 Respiratory protection program
Source: OSHA SEP
Silicosis Prevention Program
 Hygiene
facilities and clothing change
areas
 Recordkeeping
 Personal exposures below the PEL OR
facility has an abatement program that
provides interim worker protection
 Housekeeping program
 Regulated areas
Source: OSHA SEP
Prevention of Silica Related
Diseases
 250
Worker deaths per year
 Silicosis
 Silicosis/TB
 Lung Cancer
Health Effects
 Acute
- intense crystalline silica
exposure
– acute silicosis (silico-proteinosis)
– inflammation in the gas exchange area
of the lung
– fibrosis
Health Effects

Accelerated - more intense exposure over 5 to 15
years
– silicosis
– smaller fibrotic nodules
– massive fibrosis in the mid-zones of the lungs
– shortness of breath
– fever
– bluish skin at ear lobes or lips
Health Effects

Chronic - 20 to 45 years prolonged exposure to
crystalline silica
– silicosis
– nodular lesions in upper lobes
– shortness of breath with exertion
– cough and expectoration
– fatigue
– loss of appetite
– chest pain (airway obstruction)
* x-ray (after 15-20 years) *
Common Hazard
 Abrasive
 Paint
Blasting
Removal
 Renovation
 Road
& Demolition
Repair
Exposure Controls
Substitution
 Coal
slag (black beauty)
 Steel grit
 Aluminum oxide
 Wild stuff (frozen co2,
walnut shells, baking soda)
Exposure Controls
Wet Methods
 Water
suppression of dust
 Very effective method
 May be less efficient
 Requires supply of water and clean
up
Exposure Controls
 Power
tools with HEPA exhaust