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DEPARTMENT OF LABOR & ECONOMIC GROWTH DIRECTORS OFFICE OCCUPATIONAL HEALTH STANDARDS
MIOSHA-STD-1241 (09/05)
Pages 7



DEPARTMENT OF LABOR & ECONOMIC GROWTH
DIRECTORS OFFICE
OCCUPATIONAL HEALTH STANDARDS

Filed with the Secretary of State on January 1, 1975

This rule takes effect 15 days after filing with the Secretary of State

Visit our web site at: www.michigan.gov/mioshastandards

PART 381. IONIZING RADIATION

Rule 2410 Ionizing Radiation
(Source: 1910.96 -entire section, except as noted)
(1) Definitions applicable to this rule.
(a) "Radiation" includes alpha rays, beta rays, gamma
rays, X-rays, neutron, high-speed electrons, high-
speed protons, and other atomic particles; but such
term does not include sound or radio waves, or
visible light, or infrared or ultraviolet light.
(b) "Radioactive material" means any material which
emits, by spontaneous nuclear disintegration,
corpuscular or electromagnetic emanations.
(c) "Restricted area" means any area access to which
is controlled by the employer for purposes of
protection of individuals from exposure to radiation
or radioactive materials.
(d) "Unrestricted area" means any area access to which
is not controlled by the employer for purposes of
protection of individuals from exposure to radiation
or radioactive materials.
(e) "Dose" means the quantity of ionizing radiation
absorbed, per unit of mass, by the body or by any
portion of the body. When the provisions in this rule
specify a dose during a period of time, the dose is
the total quantity of radiation absorbed, per unit of
mass, by the body or by any portion of the body
during such period of time. Several different units of
dose are in current use. Definitions of units used in
this rule are set forth in paragraphs (f) and (g) of this
subsection.
(f) "Rad" means a measure of the dose of any ionizing
radiation to body tissues in terms of the energy
absorbed per unit of mass of the tissue. One rad is
the dose corresponding to the absorption of 100
ergs per gram of tissue (1 millirad (mrad) = 0.001
rad).
(g) "Rem" means a measure of the dose of any ionizing
radiation to body tissue in terms of its estimated
biological effect relative to a dose of 1 roentgen (r)
of Xrays (1 millirem (mrem) = 0.001 rem). The
relation of the rem to other dose units depends upon
the biological effect under consideration and upon
the conditions for irradiation. Each of the following is
considered to be equivalent to a dose of 1 rem:
(i) A dose of 1 (r) due to X- or gamma radiation;
(ii) A dose of 1 rad due to X-, gamma, or beta
radiation;
(iii) A dose of 0.1 rad due to neutrons or high-
energy protons;
(iv) A dose of 0.05 rad due to particles heavier
than protons and with sufficient energy to
reach the lens of the eye;
(v) If it is more convenient to measure the neutron
flux, or equivalent, than to determine the
neutron dose in rads, as provided in
subdivision (iii) of this paragraph, 1 rem of
neutron radiation may, for purposes of the
provisions in this rule may be assumed to be
equivalent to 14 million neutrons per square
centimeter incident upon the body; or, if there
is sufficient information to estimate with
reasonable accuracy the approximate
distribution in energy of the neutrons, the
incident number of neutrons per square
centimeter equivalent to 1 rem may be
estimated from Table G-17.

TABLE G-17--NEUTRON FLUX DOSE EQUIVALENTS
Neutron energy
(million
electron volts
(Mev))
Number of neutrons
per square
centimeter
equivalent to a dose
of 1 rem
(neutrons/cm
2
)
Average flux to
deliver 100
millirem in 40
hours
(neutrons/cm
2
per
sec.)
Thermal 970
x
10
6
670
0.0001 720
x
10
6
500
0.005 820
x
10
6
570
0.02 400
x
10
6
280
0.1 120
x
10
6
80
0.5 43
x
10
6
30
1.0 26
x
10
6
18
2.5 29
x
10
6
20
5.0 26
x
10
6
18
7.5 24
x
10
6
17
10 24
x
10
6
17
10 to 30
14 x 10
6
10

(h) For determining exposures to X- or gamma rays up
to 3 Mev., the dose limits specified in this rule may
be assumed to be equivalent to the "air dose". For
the purpose of this rule "air dose" means that the
dose is measured by a properly calibrated
2
appropriate instrument in air at or near the body
surface in the region of the highest dosage rate.
(2) Exposure of individuals to radiation in restricted areas.
(a) Except as provided in paragraph (b) of this
subsection, no employer shall possess, use, or
transfer sources of ionizing radiation in such a
manner as to cause any individual in a restricted
area to receive in any period of one calendar
quarter from sources in the employer's possession
or control a dose in excess of the limits specified in
Table G-18.
TABLE G-18

Rems per calendar quarter
Whole body: Head and trunk;
active blood-forming organs;
lens of eyes; or gonads
1-1/4
Hands and forearms; feet
and ankles
18-3/4
Skin of whole body
7-1/2

(b) An employer may permit an individual in a restricted
area to receive doses to the whole body greater
than those permitted under paragraph (a) of this
subsection, so long as:
(i) During any calendar quarter the dose to the
whole body shall not exceed 3 rems; and
(ii) The dose to the whole body, when added to
the accumulated occupational dose to the
whole body, shall not exceed 5 (N-18) rems,
where "N" equals the individual's age in years
at his last birthday; and
(iii) The employer maintains adequate past and
current exposure records which show that the
addition of such a dose will not cause the
individual to exceed the amount authorized in
this paragraph. As used in this paragraph,
"dose to the whole body" shall be deemed to
include any dose to the whole body, gonad,
active blood-forming organs, head and trunk,
or lens of the eye.
(c) No employer shall permit any employee who is
under 18 years of age to receive in any period of
one calendar quarter a dose in excess of 10 percent
of the limits specified in Table G-18.
(d)
"Calendar quarter" means any 3-month period
determined as follows:
(i) The first period of any year may begin on any
date in January: Provided, That the second,
third, and fourth periods accordingly begin on
the same date in April, July, and October,
respectively, and that the fourth period extends
into January of the succeeding year, if
necessary to complete a 3-month quarter.
During the first year of use of this method of
determination, the first period for that year
shall also include any additional days in
January preceding the starting date of the first
period; or
(ii) The first period in a calendar year of 13
complete, consecutive calendar weeks; the
second period in a calendar year of 13
complete, consecutive weeks; the third period
in a calendar year of 13 complete, consecutive
calendar weeks; the fourth period in a calendar
year of 13 complete, consecutive calendar
weeks. If at the end of a calendar year there
are any days not falling within a complete
calendar week of that year, such days shall be
included within the last complete calendar
week of that year. If at the beginning of any
calendar year there are days not falling within
a complete calendar week of that year, such
days shall be included within the last complete
calendar week of the previous year; or
(iii) The four periods in a calendar year may
consist of the first 14 complete, consecutive
calendar weeks; the next 12 complete,
consecutive calendar weeks, the next 14
complete, consecutive calendar weeks, and
the last 12 complete, consecutive calendar
weeks. If at the end of a calendar year there
are any days not falling within a complete
calendar week of that year, such days shall be
included (for purposes of this rule) within the
last complete calendar week of the year. If at
the beginning of any calendar year there are
days not falling within a complete calendar
week of that year, such days shall be included
(for purposes of this rule) within the last
complete week of the previous year.
(e) No employer shall change the method used by him
to determine calendar quarters except at the
beginning of a calendar year.
(3) Exposure to airborne radioactive material.
(a)
No employer shall possess, use or transport
radioactive material in such a manner as to cause
any employee, within a restricted area, to be
exposed to airborne radioactive material in an
average concentration in excess of the limits
specified in Table 1 of Appendix B to 10 CFR Part
20. The limits given in Table 1 are for exposure to
the concentrations specified for 40 hours in any
workweek of 7 consecutive days. In any such period
where the number of hours of exposure is less than
40, the limits specified in the table may be increased
proportionately. In any such period where the
number of hours of exposure is greater than 40, the
limits specified in the table shall be decreased
proportionately.
(b)
No employer shall possess, use, or transfer
radioactive material in such a manner as to cause
any individual within a restricted area, who is under
18 years of age, to be exposed to airborne
radioactive material in an average concentration in
excess of the limits specified in Table II of Appendix
B to 10 CFR Part 20. For purposes of this
paragraph, concentrations may be averaged over