LSB No. 688

December 2, 1999

To: Chiefs of Prefectural Labour Standards Bureaus

From: Director General, Labour Standards Bureau, Ministry of Labour

Following the detection of dioxins in soil and elsewhere at waste incineration facilities site, there has been concern over possible environmental pollution and health impairment of workers caused by dioxin from such facilities. In connection, the results of a survey conducted by the Ministry of Labour have established that, depending on conditions in the work environment, workers employed at such facilities are at risk of exposure to dioxins.

Further, the Basic Policies for the Promotion of Dioxin Countermeasures decided at the ministerial conference on countermeasures against dioxin of March 30, 1999, recommend "promotion of countermeasures including establishment of an occupational health administration system, measurement and improvement of the working environment, and use of appropriate personal protective equipment in order to prevent worker exposure" and "fact-finding surveys of the state of workers' health and the working environment."

Accordingly, with the basic issue of Notification No. 231 dated April 7, 1999, orders have been given for the completeness of the Dioxin Countermeasures for Waste Incineration Facilities announced in July 1998.

In addition, in June 1999, the Ministry of Health and Welfare and the Environment Agency revised the tolerable daily intake (TDI) of dioxins, and in July of the same year the law regarding special dioxin countermeasures was established. The Ministry of Labour likewise must now take steps to ensure improved implementation of measures to prevent worker exposure to dioxins.

Accordingly, with regard to measures to be taken by enterprises to prevent dioxin exposure in workers employed at waste incineration facilities, Guidelines of Measures to Prevent Health Impairment by Dioxins have been formulated as per the attached document. Notification to relevant local self-government bodies and employers and due enforcement is requested.

Attached document

1. Purpose

Following the detection of dioxins in soil and elsewhere at waste incineration facilities site, there has been concern over possible environmental pollution and health impairment of workers caused by dioxin from such facilities.

According to the results of a survey conducted by the Ministry of Labour, depending on conditions in the working environment, workers employed at such facilities are at risk of exposure to dioxins.

Further, the Basic Policies for the Promotion of Dioxin Countermeasures decided at the ministerial conference on countermeasures against dioxins of March 30, 1999, recommend "promotion of countermeasures including establishment of an occupational health administration system, measurement and improvement of the working environment, and use of appropriate personal protective equipment in order to prevent worker exposure" and "fact-finding surveys of the state of workers' health and the working environment."

Accordingly, the present Guidelines have been formulated with regard to measures to be taken by employers to prevent dioxin exposure in workers employed at waste incineration facilities.

The items stipulated in the present Guidelines shall in principle be implemented by the employers hiring the workers to undertake the relevant operations, where necessary on the basis of discussions or joint action with the facility administrator; however, in the case of items 3 (1), 5 and 7, the facility administrator shall be chiefly responsible for implementation.

2. Relevant Operations

The operations covered by the present Guidelines shall be the operations listed below (hereinafter "incineration facility operations") as conducted at general waste incineration facilities, industrial waste incineration facilities, etc., (hereinafter "incineration facilities").

(1) Operations conducted inside incineration furnaces and dust collectors, etc., such as clearing of ash, inspection and maintenance.

(2) The following operations conducted outside of incineration furnaces and dust collectors, etc.:

[a] Operations involving handling of incineration ash such as compaction and transport of the ash.

[b] Operations consisting of assistance or watch of those in (1) above.

[c] Operation, inspection, maintenance, etc., or cleaning of incineration furnaces and dust collectors or other devices.

3. Establishment of a System for Promotion of Dioxin Countermeasures

(1) Items to be implemented by facility administrators

[a] Dioxin countermeasure committee

Employers managing incineration facilities shall establish a dioxin countermeasure committee composed of an industrial physician, health supervisors, site managers and other persons, which shall formulate a promotion plan for prevention of dioxin exposure (hereinafter "promotion plan") incorporating the measures stipulated in the present Guidelines and specific measures for the implementation of the same.

[b] Organization for consultation with commissioned employers, subcontractors, etc.

In cases where employers managing incineration facilities commission all or part of the incineration operations to another entity or hire a subcontractor, an organization for consultation shall be established in which all parties involved shall participate and in which shall be debated a promotion plan to prevent dioxin exposure in workers carrying out the relevant operations.

[c] Sections and personnel responsible for countermeasures

In order to ensure appropriate implementation of the measures stipulated in the present Guidelines, employers managing incineration facilities shall, when elaborating measures for the prevention of worker exposure to dioxins, appoint a section and member(s) of staff responsible for dioxin countermeasures and charge them with the following duties:

(a) Management of the dioxin countermeasure committee

(b) Management of the organization for consultation mentioned in 3. (1) [b] above

(c) Communication of the promotion plan to commissioned employers and relevant subcontractors

(d) Other activities relating to the implementation of the promotion plan

(2) Items to be implemented by commissioned employers and subcontractors

Employers undertaking all or part of the incineration operations as a commissioned operation or as a subcontractor shall appoint a member or members of staff responsible for dioxin countermeasures to implement countermeasures on the basis of the promotion plan.

4. Occupational Health Education

Workers hired to perform incineration facility operations shall receive occupational health education regarding the following items:

(1) Description, toxicity, etc., of dioxins

(2) Measures to reduce exposure to dioxins

(3) Work procedures

(4) Devices for sealing the emission source, devices for automated or remote operation of work procedures, inspection prior to operation of local exhaust system, etc.

(5) Types, properties and use of respiratory protective equipment and maintenance and management thereof

(6) Action in the event of accident, etc.

5. Measures to Reduce Dioxin Exposure Based on Measurement of the Working Environment and Evaluation Thereof

At work sites where incineration facility operations (excluding the operations in 2 (1) above) are regularly undertaken, measurement of dioxin concentration in the working environment and evaluation of the results thereof shall be undertaken according to the methods described in the appendix hereto; the measurement records shall be retained for 30 years; and in work areas which, on the basis of evaluation results, fall into the control class 2 or control class 3, prevention of generation and emission of incineration ash and other dust particles shall be undertaken according to the methods listed below or other similar methods:

(1) Improvement of the incineration process and work processes

(2) Sealing of the emission source

(3) Introduction of automated and/or remote operation

(4) Installation of local exhaust system and dust collectors

(5) Humidification of the work site

6. Use of Personal Protective Equipment, Etc.

As a measure to reduce worker exposure to dioxins during incineration facility operations, the measures stipulated for each of the operations listed below shall be taken.

(1) Operations mentioned in 2 (1) above

Workers shall be required to use an air-line mask, hose mask or respiratory protective equipment with equivalent or superior capacity and impermeable protective clothing, gloves and eye protectors,etc..

(2) Operations mentioned in 2 (2) [a] and [b] above

Workers shall be required to use a dust mask which has passed a model examination or other effective respiratory protective equipment and work clothing, protective gloves and eye protectors resistant to the adhesion of dust.

(3) Operations mentioned in 2 (2) [c] above

When operations are conducted at work sites which, even after implementation of the measures stipulated in 5 above, fall into the control class 2 or control class 3, the measures stipulated in 6 (2) above shall be taken; these measures shall also be taken in cases where such operations are conducted on a temporary basis at a work site where they are not regularly undertaken.

7. Provision of Rest Places, Etc.

(1) Provision of rest places

Where workers are employed to carry out incineration operations, a rest place shall be provided outside the work site where the incineration operations are conducted. However, if it is not practicable to provide a rest place outside the work site where the incineration operations are conducted, the rest place shall be located within a place of control class 1.

(2) Measures to be taken in the rest place

The following measures shall be taken to prevent contamination of the rest place by incineration ash or similar substances adhering to the work clothing of the workers.

[a] The entrance of rest places which are of an enclosed construction with no windows or other apertures shall be provided with an air shower; in addition there shall be a water flow or an appropriately moisturized mat or other device such that incineration ash or similar substances adhering to footwear are removed.

[b] The entrance of rest places which are not of an enclosed construction shall be provided with an electrical cleaning machine for removal of incineration ash, etc., adhering to work clothing; in addition, there shall be a water flow or an appropriately moisturized mat or other device such that incineration ash or similar substances adhering to footwear are removed.

[c] The floor shall be cleaned at least once a day.

(3) Measures to be taken at locations outside the rest place

In offices and other locations frequented by workers engaged in incineration operations, measures shall be taken to prevent contamination of the place by incineration ash or similar substances adhering to the work clothing, etc., of the workers.

8. Maintenance, Etc., of Work Clothing, Etc.

Since work clothing contaminated with incineration ash containing dioxins may cause secondary dust generation, its removal from the work site shall be forbidden, and such work clothing, etc., shall be stored separately from other clothing, etc., and measures shall be taken to swiftly decontaminate work clothing, etc.

9. Forbidding of Tobacco Smoking, Etc.

At work sites where incineration operations are carried out, workers shall be forbidden to smoke tobacco or drink.

10. Working Records

Regarding incineration operations, a record shall be kept of the names of the workers, the names of the operations performed, the time periods during which they are performed, etc., and the records shall be retained for 30 years.

11. Special Considerations for Female Workers

As a special consideration to protect motherhood, females shall not be permitted to engage in the operations described in 2 (1) above.

1. Working Environment Measurement

When measuring the atmospheric concentration in the working environment of dioxins (polychlorinated dibenzoparadioxin, polychlorinated dibenzofuran and coplanar PCB, hereinafter "dioxins"), the following methods shall be used in accordance with the Working Environment Measurement Standards (Ministry of Labour Notification No. 46 1976).

(1) Frequency of measurement

[a] Measurement shall be performed regularly at least once every six months.

[b] If major changes are made to the facilities, equipment, work procedure or working methods, a fresh measurement shall be made.

(2) Timing of measurement

The measurement shall be timed to take place under normal operating conditions as regards use of devices such as incineration furnaces and dust collectors and other work operations.

If the work site is outdoors, measurement during unfavorable weather conditions such as rain or strong wind shall be avoided.

(3) Measurement points

[a] For indoor work places

The following measurements shall be made:

(a) In case of A-sampling, vertical and horizontal lines are drawn at equal intervals of not more than 6m on the floor of unit work area(refers to such a necessary section that is designated for working environment based on the condition of distribution of harmful substances and range of movement of workers with in the area of a workshop concerned herein after the same shall apply) and a sampling point is provided at each intersection of those lines at a position 50 to 150cm above the floor(except such a point where the measurement is very difficult due to equipment etc..)

In case of A-sampling, sampling points shall be provided at not less than 5 proper points per unit work area.

(b) In case of B-sampling, at such a unit work area where work is performed at a place in close vicinity to the source of emission of dust, in addition to the measurement prescribed in (a) ,measurement shall be made at such a time when the concentration of dust in the air seems to become the highest of those hours during which the work is performed at such a position where the work is performed.

[b] For outdoor work places

Measurement shall be carried out as per B-sampling at a place in close vicinity to the source of emission of dust.

(4) Measurement of atmospheric dioxin concentration

Since almost all dioxin is found adherent to dust, it is possible to calculate atmospheric dioxin concentration by first calculating the proportion of dioxin in dust and then multiplying this by the total amount of dust in the atmosphere.

It is therefore acceptable to make parallel measurements to determine the value of D (as in c. below) and to use this value again in subsequent calculations. However, if major changes are made to the facilities, equipment, work procedure or working methods, the value of D should be recalculated.

[a] Measurement of total atmospheric dust concentration

Measurement of total atmospheric dust concentration shall be made by the filtration sampling method and the gravimetric analysis. The method of sample collection shall be to use a low-volume air sampler containing an open-face holder with a glass-fiber filter paper and intake of 20 to 30 liters per minute. In A-sampling and B-sampling, the duration of sampling at each sampling point shall be at least 10 minutes.

[b] Parallel measurements

(a) Parallel measurement shall be conducted at one point at least for each unit work area(if operation performed outdoors, at a place in close vicinity to the source of emission of dust ), the value of D calculated as in c. below, and the maximum value for D used in the determination of dioxin concentration as in d. below.

(b) Measurement of total atmospheric dust concentration at the parallel measurement points shall be performed during the same time and in parallel with the measurements in (c) below.

(c) Measurement of atmospheric dioxin concentration at the parallel measurement points shall be conducted by the filtration sampling method and by gas chromatography, mass spectrometry or an analysis method with equivalent or superior capacity. The method for collection of samples shall be with a high-volume air sampler and intake of 500 to 1000 liters a minute. The duration of sampling shall be long enough for at least 10 mg of dust to accumulate.

[c] Calculation of value of D

Using the values for total atmospheric dust concentration and atmospheric dioxin concentration measured at the parallel measurements points, the value of D shall be calculated from the following formula:

where:

ADC = Atmospheric dioxin concentration (pgTEQ/m³)

TADC = Total atmospheric dust concentration (mg/m³)

[d] Determination of atmospheric dioxin concentration

Based on the value of D calculated in [c] above, it shall be able to calculate the value of atmospheric dioxin concentration (ADC) using the total atmospheric dust concentration (TADC) as follows:

where:

ADC = Atmospheric dioxin concentration (pgTEQ/m³)

TADC = Total atmospheric dust concentration (mg/m³)

2. Evaluation of Results of Working Environment Measurement

Evaluation of the results of working environment measurement shall be conducted according to the following methods in accordance with the Working Environment Evaluation Standards (Ministry of Labour Notification No.79 1988).

(1) Administrative Control Level

The administrative control level for dioxin shall be 25 pgTEQ/m³.

(2) Method for determination of control class

[a] For indoor work places

Evaluation of the results of working environment measurement shall consist of classification of each unit work area as a control class 1, 2 or 3. First evaluation value and second evaluation value are values calculated according to Paragraph 3 of the Working Environment Evaluation Standards.

(a) Control class 1:Both 1st evaluation and measured value of B-sampling(in cases where B-sampling was carried out at more than 2 sampling points,the largest value shall be adopted ,the same applies in subsections (b) and (c) below) are less than administrative control level.

(b) Control class 2:2nd evaluation value is equal to or less than administrative control level, and measured value of B-sampling is equal to or less than 1.5 times administrative control level (but excluding cases classified as control class 1).

(c) Control class 3:2nd evaluation value is more than administrative control level or measured value of B-sampling is more than 1.5 times administrative control level.

[b] For outdoor work places

Evaluation of the results of working environment measurement shall consist of classification of each places in close vicinity to the source of emission of dust as a control class 1,2,or 3.

(a) Control class 1: A measured value of B-sampling is less than administrative control level.

(b) Control class 2 :A measured value of B-sampling is equal to or more than administrative control level and the value is equal to or less than 1.5 times administrative control level.

(c) Control class 3 : A measured value of B-sampling is more than 1.5 times administrative control level.