Fact Sheet Tunnel Work

(Switzerland)

I. Description of work environment and exposures

1.1. Work environment

Tunnel come in every shape, diameter, function and length; screwing themselves through different kinds of mud, ice, rock and gravel. However, in most cases there is a rock overlay above the tunnel, which may be just a few but up to several hundred meter high (e.g. in Switzerland up to 1600m).
Further, tunnel come in lengths of a few dozen to several km (in Switzerland up to 57km). This determines both the access and time required to get in and out as well as emergency evacuation routes. Furthermore, the rock overlay determines the climate, especially heat exposure, as well as water pressure and gas release. Moreover, worker get exposed to everything what’s in, or comes alongside with, the rock. Besides climatic conditions, confined spaces are a typical issue; either in tunnel drilling of or maintenance work on drilling machines or installation shafts. From both the worker’s and exposure perspective, the work environment changes dramatically from first drilling explorations up to the final test on technical installations before delivery or later maintenance work during full operation.

1.2. Possible exposures in tunnel work:

Climate (heat, up to 70°C with high humidity -> cardiopulmonary demanding, water loss, heat stroke)
Noise, vibration, shockwaves from explosive drift
Dust (Quartz -> silicosis; Asbestos -> lung cancer; diesel fumes -> lung cancer; metal dust -> blood pressure)
Chemicals (e.g. concrete -> skin irritation; acrylamide -> c/p nerve damage)
Vapors, aerosols (e.g. vapors from rock drilling ->skin & lung irritation)
Flammable Gases
Pressure, e.g. at the shield of the drilling machine, as peaks during detonations
Radiation (e.g. rock may contain Uranium, Radon gas)
Shift work
Artificial light (no daylight -> stress hormones)
Mechanical & electrical hazards from machines, installations, tunnel collapse, rock bomblets by blasting operations

1.3. Overall, the risk assessment will base on the factors

Exposures (chemical, physical, climate, radiation, lighting, etc)
Exposure time, exposure ways (e.g. skin, lung ingestion), pattern
Individual properties
Preventive measures in place (e.g. cooling cabin, beverages)
Prevalence / likelihood of occurrence

II. Personal protective devices

Jumper suit (clo 1-1.5), safety shoes, helmet, gloves (total clo 1.5-2.5)
FFP3 /half-mask or gas mask if requiredEar protectors, protective goggles
Rebreather
PID (methane gas detector)

III. Health demands

No pregnancy (if women are allowed at all in tunnel work)
Good physical health, no cardiovascular or pulmonary diseases
Sufficient vision (alarms may be just visual in noisy environments)
Intact equilibrioception
Intact eardrum
Sufficient hearing
No claustrophobia

IV. Medical examination

General double approach: workplace- and person-orientated examinations

4.1 Pre/post-employment

General eligibility check for tunnel work; based on national legislation; further drop-out check for possible occupational health problems after tunnel work or retirement; comprising of

Occupational anamnesis
General health check
Lung x-ray
Pulmonary function test
EKG, plus exercise-EKG
Lab tests (blood, liver function, renal function)

4.2 Periodically (2-3 yrs interval):

Eardrum and inner ear; mandatory for all workers in special pressurized environments, e.g. in front of the shield of the drilling machine
Hearing ability; mandatory for all in noisy environments
Lung function and x-ray; mandatory for all exposed to silica dust
EKG plus exercise-EKG, mandatory for all in pressurized a/o heat stress
Preventive examinations due to individual needs, e.g. due to allergic reactions to chemicals or known medical conditions, e.g. skin or lung problems
pattern due to actual exposure situation and individual needs and health conditions
Additional tests by specialists in cases of inconclusive aptitude for tunnel work

V. Medical examination methods

5.1 Extensive occupational anamnesis

5.2 Check for any starting signs of an occupational disease, e.g.

Aural examination
Lung function, thorax x-ray; if required ct scan
Biomonitoring, e.g. if exposed to acrylamide or other chemicals
Allergy tests & skin examination

VI. Occupational medical expertise and advice

6.1 Improvement of work environment

Only possible by regulations and company standards

6.2 Improvement of personal behavior

Worker instruction of self-examination/observation on perceived exhaust
tion, dizziness, skin problems and general health

VII. Re-Integration management of long term sick employees

Depends on actual health problems; however, in most cases any medical condition
other than unlimited workability won’t allow a return to tunnel work

VIII. Work place health management options

sufficient food & beverage supplied at the tunnel workplace
cooling cabins
on-site worker health survey by trained supervisor; e.g. for heat stress overload
employer offers free medical checkups for all tunnel workers, additional to mandatory check-ups

Suggested literature

Bakke B 2014-Characterization of Occupational Exposure to Air Contaminants in
Modern Tunnelling Operations
Cohen JM 2013-Air Quality Regulation in Metropolitan Railways
DGUV 2010-Leitfaden für Betriebsärzte zur arbeitsmedizinischen Untersuchung
EKAS Richtlinie 6514-2005-Untertagarbeiten
Hurley JF 2003-Assessment of health effects of long-term occupational exposure to tunnel dust in the London Underground
Oliver LC 2006-Airway disease in highway and tunnel construction workers exposed
to silica
Palmer KT 2015-Rheumatic effects of vibration at work
SUVA 2012-Berufliches Tauchen und Arbeiten im Überdruck-2869_08
SUVA-Arbeitsmedizinische Prophylaxe bei Arbeiten im Untertagebau im feuchtwarmen Klima-2869_26_D
WorkCover NSW 2006-Code of Practice for Tunnels Under Construction

Tunnel Work