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JICOSH Home > Laws > Ordinance on Industrial Safety and Health

Ordinance on Industrial Safety and Health
Ministry of Labour Ordinance No. 32 of September 30, 1972

Latest Amendments:
Ministry of Health, Labour and Welfare Ordinance No. 47 of March 30, 2007
In Japanese

Update : 2008.03.28

Part II Safety Standards

Chapter VI Prevention of Dangers in Excavating Work, etc.

Section 1 Open-Cut Excavating Work
Subsection 1 Time and Procedure of Excavating Work, etc.

Article 355 (Investigation on Work Place, etc.)

(1) The employer shall, in the case of carrying out an excavating work of natural ground, and when it is liable to cause dangers to workers due to collapse of natural ground, broken underground-installed objects, etc., investigate in advance the natural ground of the work place and its surroundings as to the following matters by boring or other suitable methods, and determine the time and procedures of excavation on the in conformity with what is known by the investigation and carry out by the determinations thereof:
- (i) Landform, nature of the soil and conditions of strata.
- (ii) Existence and conditions of cracks, water content, spring water and freezing.
- (iii) Existence and conditions of underground-installed objects, etc.
- (iv) Existence and conditions of high-temperature gas and vapor.

Article 356 (Standard of Gradient of Excavation Surfaces)

(1) The employer shall, when carrying out excavating work of natural ground (excluding natural ground composed of rock beds without cracks that cause collapse or fall of rocks, natural ground composed of sand, and natural ground in a condition which is liable to collapse due to blasting etc., hereinafter the same shall apply in this Article) by the method of manual excavation (meaning the method of excavation without excavating machines such as power shovel and tractor shovel; hereinafter the same shall apply in next Article), make the gradient of the excavation surface (in the case that there is a horizontal step with a depth of 2 m or more on the excavation surface, each excavation surface divided by the said horizontal step; the same shall apply hereinafter) the value listed in the right column of the following table or less corresponding to the type of the ground listed in the left column and the height of the excavation surface listed in the middle column of the same table, respectively:

Type of the natural ground	Height of the excavation surface (m)	Gradient of the excavation surface (degree)
natural ground composed of rock beds or hard clay	Less than 5	90
natural ground composed of rock beds or hard clay	5 or more	75
Other natural ground	Less than 2	90
	2 or more but less than 5	75
	5 or more	60

(2) In the case prescribed in the preceding paragraph, when it is impossible to calculate the gradient due to some parts of the excavation surface differ in slope from other parts, the slopes of each part of the excavation surface shall be so maintained that the danger of collapse may not become greater than that as prescribed in the same paragraph.

Article 357

(1) The employer shall, when carrying out an excavating work of natural ground composed of sand or of natural ground in a condition which is liable to collapse due to blasting, etc., by manual excavation, comply with the following provisions:
- (i) For natural ground composed of sand, to make the gradient of the excavation surface 35 degrees or less, or make the height of the excavation surface less than 5 m.
- (ii) For natural ground in a condition which is liable to collapse due to blasting, etc., to make the gradient of the excavation surface 45 degrees or less, or make the height of the excavation surface less than 2 m.
(2) The provisions of item (ii) of the preceding Article shall apply mutatis mutandis to the case that it is impossible to calculate the gradient because some parts of the excavation surface of the natural ground set forth in the preceding paragraph differ in slope from other parts.

Article 358 (Checkup)

(1) The employer shall, when carrying out the work of open-cut excavation, take the following measures to prevent workers from dangers due to collapse of natural ground or fallen earth and rocks:
- (i) To designate a checker and have the said checker carry out a checkup on the natural ground of the work place and its surroundings before commencing the work for the day, after a heavy rain and an earthquake of medium shock or heavier as to the existence and conditions of loose stones and cracks, and changes in water content, spring water and freezing.
- (ii) To designate a checker and have the said checker carry out a checkup on the existence and conditions of loose stones and cracks, after blasting operations, at places where the said blasting operations have been carried out and their surroundings.

Article 359 (Appointment of an Operations Chief of Excavating Natural Ground)

(1) The employer shall, as regards the work set forth in item (ix) of Article 6 of the Order, appoint an operations chief of excavating natural ground from the persons who have completed the skill training course for operations chief of excavating natural ground and shoring.

Article 360 (Duties of an Operations Chief of Excavating Natural Ground)

(1) The employer shall have an operations chief of excavating natural ground carry out the following matters:
- (i) To decide a work method and supervise the work directly.
- (ii) To check an instrument and a tool, and remove defective ones.
- (iii) To monitor the use of a safety belt, etc., and a safety helmet.

Article 361 (Prevention of Dangers Due to Collapse of Natural Ground, etc.)

(1) The employer shall, in the case of carrying out the work of open-cut excavation, and when it is liable to cause dangers to workers due to collapse of natural ground or fallen earth and rocks, take measures to prevent dangers, such as setting up shoring, setting up protective nets, prohibiting workers from entering etc., in advance.

Article 362 (Prevention of Dangers Due to Underground-Installed Objects, etc.)

(1) The employer shall, in the case of carrying out the work of open-cut excavation at a place adjacent to underground-installed objects, etc., or buildings of brick walls, concrete block walls, retaining walls, etc., and when it is liable to cause dangers to workers due to their collapse, not carry out the work unless measures to prevent dangers have been taken, such as reinforcing and removing them.
(2) The measure set forth in the preceding paragraph shall, in the case that it is liable to cause dangers to workers due to breakage of gas conduits exposed by open-cut excavation work, be such measures as protection of the said gas conduits by suspending protection, supporting protection, etc., or removal of the said gas conduits, etc.
(3) The employer shall, as regards the works for the protection of gas conduits prescribed in the preceding paragraph, designate a person to direct the said work, and have the said work carried out under the direct supervision by the said person.

Article 363 (Prohibition of the Use of Excavating Machine, etc.)

(1) The employer shall, in the case of carrying out the open-cut excavation work and when it is liable to cause dangers to workers due to breakage of gas conduits, underground electric line or other underground structures by the use of excavating machine, loading and transporting machines, not use the said machines.

Article 364 (Travelling Route, etc., of Transporting Machines, etc.)

(1) The employer shall, when carrying out the open-cut excavation work, determine in advance an travelling route for a transporting machine, a excavating machine and a loading machine (excluding a vehicle type construction machine and a vehicle type material handling machine, etc.; hereinafter referred to as “transporting machine, etc.” in this Chapter), and the method for those machines of entering and leaving from the loading and unloading place of the earth and rocks, and make them known to the workers concerned.

Article 365 (Arrangement of a Guide)

(1) The employer shall, in the case where carrying out the open-cut excavation work, and when a transporting machine, etc., approach the work place by backing or when it is liable to cause falling, arrange a guide and have the said person guide the said machines.
(2) The operator of the transporting machine, etc., set forth in the preceding paragraph shall follow the instruction given by the guide set forth in the same paragraph.

Article 366 (Wearing of a Safety Helmet)

(1) The employer shall, when carrying out the work of open-cut excavation, have the worker engaging in the said work wear a safety helmet in order to prevent workers from dangers due to flying or falling objects.
(2) The worker engaging in the work set forth in the preceding paragraph shall wear the safety helmet set forth in the same paragraph.

Article 367 (Maintenance of Illumination)

(1) The employer shall, as regards the place where carrying out the work of an open-cut excavation, maintain necessary illumination for carrying out the said work safely.

Section 1 Open-Cut Excavating Work
Subsection 2 Shoring

Article 368 (Material)

(1) The employer shall, as regards materials of shoring, not use those having gross damage, deformation or corrosion.

Article 369 (Structure)

(1) The employer shall make the structure of the shoring sound corresponding to landform, nature of the soil, strata, cracks, water content, spring water, freezing and underground-installed objects, etc., pertaining to the natural ground where the said shoring is installed.

Article 370 (Erection Diagram)

(1) The employer shall, when assembling shoring, prepare in advance an erection diagram, and shall assemble it under the said erection diagram.
(2) The erection diagram set forth in the preceding paragraph shall describe the arrangement, size and materials of members such as sheet piles, piles, shore laggings, walings, struts, and the time and procedure of installation.

Article 371 (Installation, etc., of Members)

(1) The employer shall, as regards installation, etc., of the members of shoring etc comply with the following provisions:
- (i) To mount walings and struts firmly on sheet piles, piles, etc., to prevent them from coming off.
- (ii) To use butt joints for jointing of compression members (excluding horizontal angle braces).
- (iii) To fasten firmly the connecting portions of struts or horizontal angle braces and the crossing portions of struts with doubling plates and bolts, or connect them by welding or other method to make them sound.
- (iv) For shoring with a middle support pole, to mount struts firmly on such middle support pole.
- (v) For the case that struts are supported by things other than the members such as the columns of a structure, to make the said supports strong enough to bear the load applied.

Article 372 (Work of Installing or Removing Struts, etc.)

(1) The employer shall, when carrying out the work set forth in item (x) of Article 6 of the Order, take the following measures:
- (i) To prohibit workers other than those concerned from entering the place where the said work is carried out.
- (ii) When raising or lowering materials, instruments or tools, to have workers use lifting ropes, lifting bags, etc.

Article 373 (Checkup)

(1) The employer shall, when having installed shoring, check the following matters once every period not exceeding seven days, after an earthquake of medium shock or heavier, and after having happened an event, which is liable to weaken the ground rapidly due to heavy rain, etc., and immediately reinforce or repair when having found any abnormalities:
- (i) Existence and condition of damage, deformation, corrosion, displacement and coming off of members.
- (ii) Degree of compression of struts.
- (iii) Condition of the connecting portions, mounting portions and crossing portions of members.

Article 374 (Appointment of an Operations Chief of Shoring)

(1) The employer shall, as regards the work set forth in item (x) of Article 6 of the Order, appoint an operations chief of shoring from the persons who have completed the skill training courses for operations chief of excavating natural ground and shoring.

Article 375 (Duties of an Operations Chief of Shoring)

(1) The employer shall have an operations chief of shoring carry out the following matters:
- (i) To decide a work method and supervise the work directly.
- (ii) To check defects in material, an instrument and a tool, and remove defective ones.
- (iii) To monitor the use of a safety belt, etc., and a safety helmet.

Section 1 Open-Cut Excavating Work
Subsection 3 Work in Caissons, etc.

Article 376 (Settling Diagram, etc.)

(1) The employer shall, when carrying out the open-cut excavation work in a caisson or in a sunk well, take the following measures to prevent dangers to workers due to rapid settling of the said caisson or sunk well:
- (i) To determine the method of excavation, the quantity of load, etc., based on a settling diagram.
- (ii) To have the height from the cutting edge to the ceiling or the girder of 1.8 m or higher.

Article 377 (Work in a Caisson, etc.)

(1) The employer shall, when carrying out the open-cut excavation work in a caisson, a sunk well, a vertical shaft, a well or other buildings or facilities similar to them (hereinafter referred to as “caissons, etc.”), take the following measures:
- (i) When the quantity of oxygen may become excessive, to designate a person in charge of measuring the concentration of oxygen, and have the said person measures the concentration.
- (ii) To provide facilities for safe ascent and descent of workers.
- (iii) When the depth of excavation exceeds 20 m, to provide devices such as a telephone, an electric bell, etc., for communication between the work place and the outside.
(2) The employer shall, in the case prescribed in the preceding paragraph, when excessive oxygen is observed as a result of the measurement set forth in item (i) of the same paragraph, or when the depth of excavation exceeds 20 m, provide facilities for sending air and feed the necessary quantity of air using the said facilities.

Article 378 (Prohibition of Work)

(1) The employer shall, when falling under any of the following each item, not carry out the open-cut excavation work in caissons, etc:
(i) When the facilities set forth in item (ii) or (iii) of paragraph (1) of the preceding Article or in paragraph (2) of the same Article are out of order.
(ii) When it is liable to cause penetrating a large quantity of water into the caissons, etc.

Section 2 Construction Work of Tunnels, etc
Subsection 1 Investigation, etc.

Article 379 (Investigation and Record)

(1) The employer shall, when carrying out the excavating work of tunnels, etc., investigate in advance the landform of natural ground and condition of the nature of the soil and strata pertaining to said excavation work by boring or other appropriate method in order to prevent workers from dangers due to cave-in, inundation, gas explosion, etc., and record the result of the investigation.

Article 380 (Construction Plan)

(1) The employer shall, when carrying out excavating work of tunnels, etc., establish in advance a construction plan in conformity with what is known by the investigation prescribed in the preceding Article, and carry out the work by the said plan.
(2) The construction plan set forth in the preceding paragraph shall be the one describing the following matters:
- (i) Method of excavation.
- (ii) Method of construction of tunnel shoring, construction of lining, disposal of spring water or flammable gas, and ventilation or illumination when these are carried out.

Article 381 (Observation and Record)

(1) The employer shall, when carrying out excavating work of tunnels, etc., observe the excavation site and surrounding natural ground every day as to the following matters in order to prevent dangers to workers due to cave-in, inundation, gas explosion, etc., and record the results of the said observation:
- (i) Conditions of nature of the soil and strata.
- (ii) Existence and condition of water content, and spring water.
- (iii) Existence and condition of flammable gas.
- (iv) Existence and condition of high-temperature gas or vapor.
(2) The observation pertaining to the matters set forth in item (iii) of the preceding paragraph shall, in the case that the excavation is carried out by the method that excavation site and its surrounding natural ground are covered with machine, be carried out using a measuring instrument .

Article 382 (Checkup)

(1) The employer shall, when carrying out construction work of tunnel, etc., (meaning an excavating work of tunnels, etc., or transportation of muck, materials, etc., or concrete placing, etc., work of lining associated with it(limited to the work carried out in the said tunnel, etc., or at a place near the said tunnel, etc.); the same shall apply hereinafter), take the following measures to prevent the dangers to workers due to cave-in or fall of rocks:
- (i) To designate a checker and have the said person check the ground in tunnels, etc., every day and after an earthquake of medium shock or heavier as to the existence and condition of loose stones and cracks, and changes in the condition of water content and spring water.
- (ii) To designate a checker and have the said person check after blasting operations the location where the said blasting operations have been carried out and its surroundings as to the existence and condition of loose stones and cracks.

Article 382-2 (Measurement, etc., of the Concentration of Flammable Gas)

(1) The employer shall, in the case of a construction work of tunnels, etc., the flammable gases are liable to be generated , designate a person charged with the measurement of the concentration of the flammable gases in order to prevent an explosion or fire and have the said person measure and record the concentration of the flammable gas at the places where the said flammable gases are liable to be generated or stagnate, every day before commencing the work for the day, after an earthquake of medium shock or heavier or when having found any abnormalities related to the said flammable gases.

Article 382-3 (Installation, etc., of Automatic Alarms)

(1) The employer shall, when it is found as a result of the measurement set forth in the preceding Article that the flammable gases exist and is liable to cause an explosion or fire, install automatic alarms at necessary places for an early detection of abnormal rise in the concentration of the flammable gases. In this case, the said automatic alarms shall have system, which is able to quickly alert workers who are working around the area of the detectors of the automatic alarms to the abnormal rises in the concentration of the said flammable gas.
(2) The employer shall, as regards the automatic alarm device set forth in the preceding paragraph, check the following matters before commencing the work for the day, and immediately repair when having found any abnormalities:
- (i) Abnormalities in the measuring gauges.
- (ii) Abnormalities in detectors.
- (iii) Function of the alarms.

Article 383 (Alteration in Construction Plan)

(1) The employer shall, in the case of carrying out excavating work of tunnels, etc., and when the construction plan set forth in paragraph (1) of Article 380 becomes unsuitable to the conditions of natural ground which was known by the observation pursuant to the provision of paragraph (1) of Article 381, the checkup pursuant to the provision of Article 382, the measurement pursuant to the provision of Article 382-2, etc., alter such construction plan without delay so that it may suit the conditions of the said natural ground, and carry out the excavating work by the changed construction plan.

Article 383-2 (Appointment of an Operations Chief of Excavating Tunnel, etc.)

(1) The employer shall, as regards the work set forth in item (x)-2 of Article 6 of the Order, appoint an operations chief of excavating tunnel, etc., from the persons who have completed the skill training course for operation chief of excavating tunnel, etc.

Article 383-3 (Duties of an Operations Chief of Excavating Tunnel, etc.)

(1) The employer shall have an operations chief of excavating tunnel, etc., carry out the following matters:
- (i) To decide a work method and arrangement of workers, and supervise the work directly.
- (ii) To check the function of an instrument, a tool, a safety belt, etc., and a safety helmet, and remove defective ones.
- (iii) To monitor the use of a safety belt, etc., and a safety helmet.

Article 383-4 (Appointment of an Operations Chief of Lining of Tunnel, etc.)

(1) The employer shall, as regards the work set forth in item (x)-3 of Article 6 of the Order, appoint an operations chief of lining of tunnel, etc., from the persons who have completed the skill training course for operations chief of lining of tunnel, etc.

Article 383-5 (Duties of an Operations Chief of Lining of Tunnel, etc.)

(1) The employer shall have an operations chief of lining of tunnel, etc., carry out the following matters:
- (i) To decide a work method and arrangement of workers, and supervise the work directly.
- (ii) To check the function of an instrument, a tool, a safety belt, etc., and a safety helmet, and remove defective ones.
- (iii) To monitor the use of a safety belt, etc., and a safety helmet.

Section 2 Construction Work of Tunnels, etc
Subsection 1-2 Prevention of Dangers Due to Cave-in, Collapse of Natural Ground, etc.

Article 384 (Prevention of Dangers Due to Cave-in, etc.)

(1) The employer shall, in the case of a construction work of tunnels, etc., and when it is liable to cause dangers to workers due to a cave-in or fall of rocks, take measure such as providing tunnel shoring, use lock bolts and removing loose stones in order to prevent the said danger.

Article 385 (Prevention of Dangers Due to Collapse of Natural Ground, etc., near the Entrance)

(1) The employer shall, in the case of construction work of tunnels, etc., and when it is liable to cause dangers to workers due to collapse of natural ground or fallen soil and stone near the entrance or exit of the said tunnels, etc., take measures such as providing shoring, setting up protective nets and removing loose stones in order to prevent the said dangers.

Article 386 (Prohibition of Entry)

(1) The employer shall not allow workers other than those concerned to enter the following places:
- (i) Places where the work to remove loose stones is being carried out or downward from the said places, where it is liable to cause dangers to workers due to fallen loose stones.
- (ii) Places where the work to reinforcing or repairing tunnel shoring is being carried out and where it is liable to cause dangers to workers due to cave-in or falling of rocks.

Article 387 (Maintenance of Visibility)

(1) The employer shall, in the case of a construction work of tunnels, etc., and when visibility in tunnels, etc., is highly limited by exhaust gas, dusts, etc., take measures such as ventilating tunnels, etc., spraying water in order to maintain the visibility necessary to carry out the said work safely.

Article 388 (Application by Analogy)

(1) The provisions of Articles 364 to 367 shall apply mutatis mutandis to construction work of tunnels, etc.

Section 2 Construction Work of Tunnels, etc
Subsection 1-3 Prevention of Explosions, Fires, etc.

Article 389 (Prohibition against Carrying Ignitable Articles, etc.)

(1) The employer shall, when it is found as a result of the measurement pursuant to the provision of Article 382-2 that flammable gas exists, exclude the case unavoidable due to the nature of the work, prohibit workers from carrying fire, matches, lighters or other ignitable articles into the inside of the tunnels, etc., and post a notice to that effect at a readily visible place near the entrance to the tunnels, etc.

Article 389-2 (Measures in the Case of Automatic Alarms Sound)

(1) The employer shall establish measures in advance that the workers concerned should take to prevent an explosion or fire due to flammable gas when the automatic alarms set forth in Article 382-3 sound, and make the said measures known to the said workers.

Article 389-2-2 (Measures to Remove Gas, etc.)

(1) The employer shall, in the case of excavating work of tunnels, etc., and when the flammable gases are liable to be generated, take measures to remove the gases by boring and other necessary measures to prevent the flammable gas from eruption in order to prevent explosion or fire due to the said flammable gas.

Article 389-3 (Measures to Prevent Fire in the Case of the Work of Gas Welding, etc.)

(1) The employer shall, in the case of construction work of tunnels, etc., and when carrying out the work of welding, cutting or heating metals using the flammable gas and oxygen inside the tunnels, etc., take the following measures to prevent fire:
- (i) To remove rags, wood chips, paper scraps or other flammables substances that exist nearby, cover them with nonflammable substance or install partitions to prevent sparks arising associate with the said work from spatter.
- (ii) To have the leader set forth in Article 257 carry out the following matters in addition to matters set forth in each item of the same Article.
  - (a) To make the location of fire extinguishing equipment and how to use it known to the worker engaging in the work.
  - (b) To monitor the work and take necessary measure when having found any abnormalities.
  - (c) To confirm that there is no danger to cause fire due to sparks, etc., after completed the work.

Article 389-4 (Person Charged with Fire Prevention)

(1) The employer shall, in the case of construction work of tunnels, etc., as regards the places inside the tunnel, etc., where fire or arc is used (excluding places where the work set forth in the preceding Article is carried out), designate a person charged with fire prevention and have the said person carry out the following matters to prevent fire:
- (i) To monitor the conditions in which fire or arc is used and take necessary measures immediately when having found any abnormalities.
- (ii) To confirm that remaining fire has been properly extinguished.

Article 389-5 (Fire Extinguishing Equipment)

(1) The employer shall, when carrying out the construction work of tunnels, etc., install the fire extinguishing equipment suited to the nature of a fire that may break out at the locations where fire or arc is used, or where a switch board, transformer or circuit breaker is installed, and make the location of the said fire extinguishing equipment and the method of use how to use it known to the workers concerned.

Article 389-6 (Construction Work of a Vertical Shaft)

(1) The provisions of the preceding three Articles shall apply mutatis mutandis to the construction work of vertical shafts.

Section 2 Construction Work of Tunnels, etc
Subsection 1-4 Evacuation, etc.

Article 389-7 (Evacuation)

(1) The employer shall, in the case of construction work of tunnels, etc., and when there is an urgent danger of an industrial accident being caused by cave-in, inundation, etc., suspend work immediately and evacuate the workers to a safety zone.

Article 389-8

(1) The employer shall, in the case of construction work of tunnels, etc., and when having found that the concentration of the flammable gas reaches 30 % of the lower explosion limit or more, immediately evacuate the workers to a safety zone, stop using fire or other ignitable articles and take measures for ventilation, etc.
(2) The employer shall, in the case prescribed in the preceding paragraph, prohibit workers other than those concerned from entering the inside of the tunnels, etc., and display a notice to that effect at a readily visible location until it is ascertained that the concentration of the flammable gas has declined below 30 % of the lower explosion limit.

Article 389-9 (Alarm Devices, etc.)

(1) The employer shall, when carrying out the construction work of tunnels, etc., install the devices listed in the following each item, corresponding to the classifications listed in the said each item, in order to give immediate warning to the workers concerned in the case of cave-in, inundation, gas explosion, fire or other emergencies, and make the places of the said devices known to the workers concerned:
- (i) When the distance from the entrance of the tunnels, etc., to the facing (hereinafter referred to as “distance to the facing” in this Subsection) reaches 100 m (excluding the case listed in the next item): Alarm devices such as sirens and emergency bells(hereinafter referred to as “alarm devices” in this Article).
- (ii) When the distance to the facing reaches 500 m: Alarm devices, and telephones, etc., or other communicating equipment (limited to those enabling communication between the inside and the outside of the tunnel, etc., hereinafter referred to as “communicating equipment” in this Article).
(2) The employer shall maintain the alarm devices and communicating equipment set forth in the preceding paragraph properly functioning at all times.
(3) The employer shall install a reserve power source, which can be used immediately when any abnormalities arise in the power source for the alarm devices and communicating equipment set forth in paragraph (1).

Article 389-10 (Apparatuses for Evacuation)

(1) The employer shall, when carrying out the construction work of tunnels, etc., provide the apparatuses listed in the following each item corresponding to the classifications listed in the said each item at suitable locations, in order to facilitate the evacuation of the workers concerned in the case of cave-in, inundation, gas explosion, fire or other emergencies, and make the locations of the said apparatuses and how to use them known to the workers concerned:
- (i) For the tunnels, etc., other than those where flammable gas exists and is liable to cause explosion or fire (excluding the case listed in item (iii)), and when the distance to the facing reaches 100 m: Flashlight or other portable lighting apparatuses (hereinafter called “portable illumination apparatuses” in this Article) and other apparatuses necessary for evacuation.
- (ii) For the tunnels, etc., where flammable gas exists and is liable to cause explosion or fire (excluding the case listed in the next item), and when the distance to the facing reaches 100 m: Survival equipment against carbon monoxide or other respiration apparatuses (hereinafter referred to as “respiration apparatuses” in this Article), portable illumination apparatuses and other apparatuses necessary for evacuation.
- (iii) When the distance to the facing reaches 500 m: Respiratory protective equipment, portable illumination apparatuses and other apparatuses necessary for evacuation.
(2) The employer shall, as regards the respiratory protective equipment set forth in the preceding paragraph, provide as many or more than the number of workers at work at any given time (excluding a person engaging in the work near the entrance, the same shall apply in the next paragraph), and maintain them properly functioning and clean at all times.
(3) The employer shall, as regards the portable illumination apparatuses set forth in paragraph (1), provide as many or more than the number of workers at work at any given time, and maintain them properly functioning at all times. However, this shall not apply in the case set froth in item (i) of the same paragraph, and when measures have been taken to secure illumination to facilitate the evacuation of workers at work at any given time as a group.

Article 389-11 (Evacuation Drill, etc.)

(1) The employer shall, when carrying out the construction work of a tunnel, etc., where the distance to the facing is expected to reach 100 m (500 m for a tunnel, etc., other than those where flammable gas exists and is liable to cause explosion or fire) or more, conduct an evacuation drill and fire fighting training (hereinafter referred to as “evacuation drill, etc.”) for the workers concerned once within the period during which the distance to the facing reaches 100 m and once every period within six months thereafter in order to prepare for cave-in, inundation, gas explosion, fire, etc.
(2) The employer shall, when having conducted the evacuation drill, etc., record the following matters and preserve the records for three years:
- (i) The date of the training conducted.
- (ii) The full name of the person who has undergone the training.
- (iii) The details of the training.

Section 2 Construction Work of Tunnels, etc
Subsection 2 Tunnel Shoring

Article 390 (Material)

(1) The employer shall not use materials having marked damage, deformation or corrosions as materials for tunnel shoring.
(2) The employer shall, as regards the wooden materials for tunnel shoring, not use unless these are of good toughness such as Japanese red pine or black pine, and free from the marked defects for strength such as cracks, worm-eaten spots, gnarls and slanted fibres.

Article 391 (Structure of Tunnel Shoring)

(1) The employer shall make the structure of tunnel shoring sufficiently sound corresponding to the condition of nature of the soil, strata, water content, spring water, cracks and loose stones pertaining to the natural ground where the said tunnel shoring was installed and method of excavation.

Article 392 (Standard Drawing)

(1) The employer shall, when constructing the tunnel shoring, prepare in advance a standard drawing, and construct such support by the said standard drawing.
(2) The standard drawing prescribed in the preceding paragraph shall describe the arrangement, size and materials of the members of tunnel shoring.

Article 393 (Construction or Alteration)

(1) The employer shall, when constructing or altering the tunnel shoring, comply with the following provisions:
- (i) To arrange a set of members composing the main members on the same plane;
- (ii) For wooden tunnel shoring, to make the degree of compression of each member of said tunnel shoring the same level.

Article 394 (Prevention of Dangers of Tunnel Shoring)

(1) The employer shall, as regards tunnel shoring, comply with the following provisions:
- (i) To take measures such as providing sill plates at the foot portion to prevent from settling.
- (ii) For steel arch shoring, to comply with followings:
  - (a) To make the distance between an interval1.5 m or less.
  - (b) To take measures such as driving wedges so that the main members display arch functions sufficiently .
  - (c) To couple firmly main members with one another using connecting bolts and connecting girders, bracings, etc.
  - (d) To provide slant props at the entrance of tunnels, etc.
  - (e) When it is liable that steel arch shoring may fall or be twisted due to longitudinal load of tunnels, etc., applied to such shoring, for example, when longitudinal length of tunnels, etc., supported by steel arch shoring is short, to provide slant props also to portions other than the portions of the entrance of such tunnels, etc., or take other measures to prevent steel arch shoring from falling or being twisted.
  - (f) When it is liable to cause dangers to workers due to fall of rocks, to provide sheet piles, wooden sheets, linier plates, etc.
- (iii) For wooden prop type shoring, to comply with followings:
  - (a) To fasten sleepers to the ground with nose girders, etc., to prevent displacement.
  - (b) To provide slant props at both ends.
  - (c) When it is liable that wooden prop type shoring may fall or be twisted due to longitudinal load of tunnels, etc., applied to such shoring, to provide slant props also to portions other than both ends or take other measures to prevent wooden prop typed shoring from falling or being twisted.
  - (d) To make the connecting portions of members fit and fasten them with clamps, etc.
  - (e) Not to arrange caps within the vertical plane including longitudinal bar braces or girders collar braces.
  - (f) To make longitudinal bar braces and girder collar braces display arch functions sufficiently.
- (iv) For tunnel shoring other than steel arch shoring and wooden prop type shoring, to provide slant props at portion of the entrance of tunnels, etc.

Article 395 (Removal of Members)

(1) The employer shall, when removing members of tunnel shoring to which a load is applied, not remove such members unless measures have been taken to remove the load applied to such members to tunnel concrete form shoring, etc.

Article 396 (Checkup)

(1) The employer shall, when having installed tunnel shoring, check the following matters every day, after an earthquake of medium shock or heavier, and immediately reinforce or repair when having found any abnormalities:
- (i) Existence and condition of damage, deformation, corrosion, displacements and coming off of members.
- (ii) Degree of compression of members.
- (iii) Conditions of the connecting portions and crossing portions of members.
- (iv) Existence and condition of settling of the foot portion.

Section 2 Construction Work of Tunnels, etc
Subsection 3. Tunnel Concrete Form Shoring

Article 397 (Material)

(1) The employer shall not use materials having marked damage, deformation or corrosion as materials for tunnel concrete form shoring.

Article 398 (Structure)

(1) The employer shall make the structure of tunnel concrete form shoring sound corresponding to the load applied to such tunnel concrete form shoring, the shape of the concrete form, etc.

Section 3 Quarrying Work
Subsection 1 Investigation, Quarrying Work Plan, etc.

Article 399 (Investigation and Record)

(1) The employer shall, when carrying out the quarrying work (meaning excavating work for collecting rocks, work cutting in-blocks, processing and transporting rocks at quarry, and other works associating with these works; the same shall apply hereinafter), investigate in advance the landform and condition of the nature of the soil and strata pertaining to the said quarrying work in order to prevent workers from dangers due to collapse of the natural ground, falling of an excavating machines, etc., and record the result of the investigation.

Article 400 (Quarrying Work Plan)

(1) The employer shall, when carrying out a quarrying work, establish in advance a quarrying work plan in conformity with what is known by the investigation pursuant to the provision of the preceding Article, and carry out the work by the said work plan.
(2) The quarrying work plan set forth in the preceding paragraph shall be the one describing the following matters:
- (i) For distinction of open casting or underground casting and for open casting, distinction of the step quarrying system, slope quarrying system or glory hole system.
- (ii) The height and gradient of the excavation surface.
- (iii) The position and depth of the steps of the excavation surface.
- (iv) The method of preventing cave-in, falls of rocks and collapse of sidewalls in the pit.
- (v) The method of blasting.
- (vi) The method of cut in-blocks.
- (vii) The place of processing rocks.
- (viii) The method of loading, transporting earth and sand or rocks and the route of transportation.
- (ix) The type and capability of excavating machines, cut in-block machines, loading machines or transporting machines to be used.
- (x) The method of disposing surface earth or spring water.

Article 401 (Checkup)

(1) The employer shall, when carrying out a quarrying work, take the following measures for preventing dangers to workers due to collapse of the natural ground or fallen earth and rocks:
- (i) To designate a checker and have the said person check on the natural ground of the work place and its surroundings, before commencing the work for the day, after a heavy rain and an earthquake of medium shock or heavier, as to existence and condition of loose stones and cracks, and as to changes in the condition of water content, spring water and freezing.
- (ii) To designate a checker and have the said person check after blasting the place where the blasting has been carried out and its surroundings as to existence and condition of loose stones and cracks.

Article 402 (Alteration in Quarrying Work Plan)

(1) The employer shall, when carrying out a quarrying work in which the quarrying work plan described in paragraph (1) of Article 400 becomes unsuitable to the conditions of natural ground which was known by the checkup, etc. pursuant to the provision of the preceding Article, etc., alter without delay the said quarrying work plan so as to suit such conditions of such ground, and carry out the quarrying work by the changed quarrying work plan.

Article 403 (Appointment of an Operations Chief of Excavating for Quarrying)

(1) The employer shall, as regards the work set forth in item (xi) of Article 6 of the Order, appoint an operations chief of excavating for quarrying from the persons who have completed the skill training course for operations chief of excavating for quarrying.

Article 404 (Duties of an Operations Chief of Excavating for Quarrying)

(1) The employer shall have an operations chief of excavating for quarrying carry out the following matters:
- (i) To decide a work method and supervise the work directly.
- (ii) To check defects in material, an instrument and a tool, and remove defective ones.
- (iii) To monitor the use of a safety belt, etc., and a safety helmet.
- (iv) To instruct in advance the method of evacuation.

Article 405 (Maintenance of Communication with Adjacent Quarries)

(1) The employer shall, to prevent workers from dangers due to collapse of natural ground, flying earth and rocks, etc., maintain communication with adjacent quarries as to the necessary matters such as time of blasting, the method of removal of loose stones which are adopted in the adjacent quarries.

Article 406 (Maintenance of Illumination)

(1) The employer shall, as regards a place where carrying out the quarrying work, maintain the necessary illumination for carrying out the said work safely.

Subsection 2 Prevention of Dangers Due to Collapse of Natural Ground, etc

Article 407 (Standards of Gradient of Excavation Surface)

(1) The employer shall, when carrying out the excavating work for quarrying (excluding the work in a pit, hereinafter the same shall apply in this Article), make the gradient of the said excavation surface the value listed in the right column of the following table or less corresponding to the type of natural ground listed in the left column of the same table and the height of the excavation surface listed in the middle column of the same table respectively. However, this shall not apply to the case of carrying out the excavating work using an excavating machines such as a power shovel and a tractor shovel, and when it is unlikely to cause danger to the operator of the said excavating machine due to collapse of natural ground or fallen earth and rocks:

Type of natural ground	Height of excavation surface (m)	Gradient of excavation surface (degree)
(1) Natural ground composed of rock beds having no cracks that may cause collapse or fall	Less than 20	90
	20 or more	75
(2) Natural ground composed of rock beds other than those listed in the preceding item	Less than 5	90
	5 or more	60
(3) Natural ground other than those listed in the preceding each item	Less than 2	90
	2 or more	45

Article 408 (Prevention of Dangers Due to Collapse, etc.)

(1) The employer shall, in the case of carrying out quarrying work (excluding work carried out in a pit) and when there exist earth and rocks, standing trees, etc., which are liable to cause dangers to workers due to collapse or fall, take measures to prevent the said dangers by removing them, providing a protective net, etc.

Article 409 (Prevention of Dangers Due to Cave-in, etc.)

(1) The employer shall, in the case of carrying out a quarrying work in a pit and when it is liable to cause dangers to workers due to cave-in, fallen rocks or collapsed sidewalls, take measures to prevent the said dangers by providing supports or residual poles, making the ceiling an arch, using lock bolts, etc

Article 410 (Prohibition of Work Adjacent to Excavation Sites)

(1) The employer shall not carry out the small cant or rock processing work adjacent to an excavation site. However, this shall not apply to when it is extremely difficult to move the said rocks to other places.

Article 411 (Prohibition of Entry)

(1) The employer shall not allow a worker to enter a place downward of place where carrying out an excavating work for collecting rocks and where it is liable to cause dangers to workers due to fallen earth and rocks.

Article 412 (Wearing of a Safety Helmet)

(1) The employer shall, when carrying out quarrying work, have the worker engaging in the said work wear a safety helmet in order to prevent workers from dangers due to flying or falling objects.
(2) A worker shall, when having been instructed to wear a safety helmet, wear the safety helmet set forth in the same paragraph.

Subsection 3 Prevention of Dangers Due to Transporting Machines, etc.

Article 413 (Travelling Route of Transporting Machines, etc.)

(1) The employer shall, when carrying out quarrying work, determine in advance the travelling route of transporting machines, etc., and cut in-block machines and the method of entering and leaving from the loading and unloading site of earth and rocks of the said machines, and make the travelling route and method known to the workers concerned.
(2) The employer shall, as regards the travelling route set forth in the preceding paragraph, take the following measure :
- (i) To maintain a sufficient width.
- (ii) To prevent collapse of shoulders.
- (iii) To prevent the ground from weakening.
- (iv) To provide signs or a railing at necessary places.
(3) The employer shall, when carrying out repair or other work for maintaining the travelling route set forth in paragraph (1), arrange a watcher or post a notice indicating that the said operation is under way.

Article 414 (Prohibition of Work on the Travelling Route)

(1) The employer shall not carry out small cant or rocks processing operation on the travelling route set forth in paragraph (1) of the preceding Article. However, this shall not apply to the case that it is inevitable and when taking the measures to prevent workers from danger due to contact with transporting machines and cut-in block machines, such as arranging a watcher or posting a notice indicating that the said operation is under way.

Article 415 (Prohibition of Entry)

(1) The employer shall, when carrying out quarrying work, not allow a worker to enter a place where is liable to cause dangers to workers due to contact with a transporting machine and a small cant machine during operation.

Article 416 (Arrangement, etc., of a Guide)

(1) The employer shall, in the case of carrying out a quarrying work, and when a transport machine, etc., and a small cant machine approach the work place by the reverse operation, or are liable to fall or turn over, arrange a guide person and have the said person guide the said transporting machine, etc., and small cant machine.
(2) The worker operating the transporting machine, etc., and the small cant machine set forth in the preceding paragraph shall follow the instruction given by the guide set forth in the same paragraph.

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Ordinance on Industrial Safety and Health Ministry of Labour Ordinance No. 32 of September 30, 1972

Latest Amendments: Ministry of Health, Labour and Welfare Ordinance No. 47 of March 30, 2007 In Japanese