CPL 2-2.6
OSHA Instruction
October 30, 1978
OSHA PROGRAM DIRECTIVE #300-2
TO: Field and National Offices/OSH
SUBJECT: Inorganic Mercury and Its Compounds
1. PURPOSE
This directive provides guidelines to be followed in inspection,
and where necessary, the issuance of citations, regarding
exposure to mercury in the workplace.
2. DOCUMENTATION AFFECTED
None
3. DOCUMENTATION REFERENCED
a. Field Operations Manual, Chapter XIII.
b. OSHA Standard Methods for Sampling Total Dust, Metal Fumes,
and Liquid Aerosols.
c. Guidelines for Controlling Occupational Exposure to Mercury
or its Inorganic Compounds.
4. BACKGROUND
a. Chemical Data. On the following page is a table of
properties of some commonly encountered mercury compounds.
A vapor pressure curve for mercury follows the table.
b. Fire, Explosion Potential, and Reactivity. Although
elemental mercury presents little danger of fire or
explosion, several mercurial compounds do pose such a
threat. Some organic mercurial compounds (e.g. mercury
fulminate) pose a serious threat, however, they are not the
concern of this directive. Among the inorganic mercurial
compounds, several are reported as being physical hazards.
Mercury nitride poses an explosion hazard when exposed to
heat. Upon contact with acids or moisture, mercuric
selenide readily liberates flammable gas. Mercurous
chromate, mercurous chloride, mercurous oxide, and mercury
ore (cinnabar) are also reported to be flammable under
certain conditions and potential physical hazards.
c. Other relevant Information. This section is for
information purposes only, not for compliance action.
(1) Common Processes. A brief description of the common
processes involved in the production, use, and
handling or mercury and its inorganic compounds is
impossible due to its numerous industrial
applications. There are over 600 major industrial
plants currently using mercury in its elemental form.
Listed below are several broad industrial areas in
which mercury is used.
PROPERTIES OF SOME MERCURY COMPOUNDS
Vapor Melting Pt. Boiling Pt.
Compound Appearance Pressure C C
---------------------------------------------------------------------
Mercury Silver-White 1mm Hg -38.87 deg 356.58 deg
(elemental) heavy, mobile, at 126.2 C
Hg liquid metal
---------------------------------------------------------------------
Mercury Ore Bright scarlet- Sublimes
(Cinnabar, red powder or at 583.5 deg
Mercuric lumps; blackens
Sulfide) on exposure to
Hgs light
---------------------------------------------------------------------
Mercuric White powder 1 mm Hg 277 deg. 302
Chloride or crystals at 136.2C
HgCl2
---------------------------------------------------------------------
Mercurous White crystals, Sublimes
Chloride or crystalline at 400 deg.
HgCl2 powder; taste-
less, odorless
_____________________________________________________________________
Mercurous Black to Decomposes
Oxide grayish-black at 100 deg C
Hg20 powder
---------------------------------------------------------------------
Mercury Brown powder Explodes
Nitride
Hg2N2
---------------------------------------------------------------------
Mercurous Red needles Decomposes
Chromate or powder
Hg2Cr04
---------------------------------------------------------------------
Mercuric Gray plates Sublimes
Selenide
HgSe
---------------------------------------------------------------------
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Continued From Above
--------------------
Mol. Solubility Flammability
Compound Weight In H20
---------------------------------------------------------------------
Mercury 200.59 Insoluble
(elemental)
Hg
---------------------------------------------------------------------
Mercury Ore 232.68 10 mg/1 When ignited in
(Cinnabar, at 18 C air, decomposes
Mercuric to metal and sulfur
Sulfide) which burns to S02.
HgS
---------------------------------------------------------------------
Mercuric 271.52 1 gm/13.5 ml
Chloride
HgCl2
---------------------------------------------------------------------
Mercurous 472.14 Practically
Chloride Insoluble
Hg2Cl2
---------------------------------------------------------------------
Mercurous 417.22 Insoluble Moderate
Oxide
Hg20
---------------------------------------------------------------------
Mercury 629.85 Severe explosion
Nitride hazard when
Hg2N2 exposed to heat.
---------------------------------------------------------------------
Mercurous 517.23 Moderate, by
Chromate chemical reaction;
Hg2Cr04 an oxidizer
---------------------------------------------------------------------
Mercuric 279.57 Readily liberates
Selenide flammable gas upon
HgSe contact with acids
or moisture
---------------------------------------------------------------------
For Graph entitled "Elemental Mercury Vapor Pressures at Various
Temperatures", see printed copy.
(a) Mechanical. Because mercury is a liquid at low
temperatures with no tendency to wet glass, it is
widely used in scientific instruments such as
thermometers and barometers. Mercury is also
used in the pressure gauges of vacuum pumps.
Potential mercury exposure is a problem not only
in the production of such instruments, but also
in research institutions where such instruments
are used extensively.
(b) Electrical. Mercury's very high level of
electrical conductivity lends itself to use in
electrical appliances. The principal use of
mercury in this category is for batteries.
Mercury is also used in rectifiers, oscillators,
power control switches, and vapor lamps.
Mercuric oxide is used extensively in dry
cells. In such a battery, the depolarizer is
composed of mercuric oxide, the electrolyte is a
strongly alkaline solution of potassium hydroxide
saturated with potassium zincate, and the anode
is of zinc. In the manufacture of these cells,
processes such as mixing, blending, and tableting
of the mercury present potential exposure
problems. The exposure may be to mercury dust or
vapor.
(c) Chlorine. The chlor alkali process uses
saturated and heated salt brine (25% NaCl in
water) to produce Cl2 (chlorine gas), H2
(hydrogen); and NaOH (sodium hydroxide) by
electrolysis. The two basic cell types are
diaphragm cells and the mercury cells. Several
different designs in each cell type can be found.
Low-voltage, high-amperage power is used in both
types. The cells are usually hooked up in
series. Diaphragm cell construction materials
include asbestos, lead, concrete, stoneware, and
possibly fiberglass. Diaphragm cells do not
contain mercury. The mercury cell uses mercury
in a two-chamber system; in the first
(electrolyzing) chamber, chlorine gas is produced
and the sodium ion is amalgamated in the mercury.
In the second (denuding) chamber, hydrogen is
formed when the amalgam contacts water and the
sodium ions combine with the remaining hydroxyl
ion (OH-) to form NaOH. The basic process
reaction for the electrolytic cells is
Na+ + Cl- + H+ + OH- -----
Na+ + 1/2Cl2 + 1/2H2 + OH-
In this process the NaOH is extremely corrosive
and mercury leaks, spillage, and recovery are
always a problem. As the cells age and become
inefficient, they have to be rebuilt. Rebuilding
is a routine operation in chlor alkali plants,
where cells are operated in batteries of tens and
even hundreds. During the rebuilding process,
the cells are leveled off, exposing the mercury
surface, creating a potential exposure problem.
(d) Paint. In the paint industry, mercury is
commonly used in its organic form. In the
primary paint industry, however, mercury may
initially be in its elemental form, even though
the final product may be organic. In such
primary manufacture, there may be some
potential mercury exposure.
OSHA Instruction CPL 2-2.6 CH-1
June 3, 1985
Office of Health Compliance Assistance
(e) Medicinals. Mercury is used primarily in dental
supply and equipment. Dentists have a variety of
uses for mercury, the primary one being a filler
for cavities. Due to mercury's use in medical
equipment and supplies, dental schools and
offices and hospitals are sites of potential
exposure.
(2) Signs and Symptoms of Intoxication. Intoxication may
occur in workers excessively exposed to mercury or to
its compounds. The exposure may be due to mercury
vapor, mist, dust, or fume, by inhalation, ingestion,
or through skin.
Two general types of mercury intoxication exist,
chronic and acute. Chronic mercury intoxication is
caused by exposure to a low concentration of mercury
over an extended period of time. Acute mercury
intoxication is due to a greater exposure and is
unrelated to time factors. Definite symptoms of
chronic mercurialism may not appear until after six
months of exposure, or longer. The symptoms are
primarily of the nervous and digestive systems.
The symptoms of overexposure to mercury may
include such personality manifestations as:
irritability, excitability, or excessive timidness.
Other symptoms include: headaches, drowsiness or
insomnia, and weakness. Many cases also include
reports of sore mouths, excessive salivation, and
perspiration. In mercury intoxication, a common
symptom is a tremor which is aggravated by emotion or
excitement. Also included in the literature as
symptoms of mercury intoxication are: loss of
appetite, weakness, digestive disorders, kidney
damage, and bleeding gums.
If an inspector is unfamiliar with biological
monitoring methods used for mercury, he or she should
check with his Senior Industrial Hygienist. When
evaluating biological symptoms, trends within groups
of employees should be noted. Elevation in mercury
levels within a group is often a more significant
finding than elevations in an individual because it
indicates a common source.
PARAGRAPH DELETED
This page replaces deleted pages 6-14.
CPL 2-2.6
OSHA Instruction
October 30, 1978
Dear Sir:
The nature of work at your establishment indicates to the
Occupational Safety and Health Administration (OSHA) that mercury in
various forms may be used in your manufacturing process. As you
know, the present permissible exposure limit to mercury is 1 mg/10 M3
(.1 mg/M3) expressed as a time-weighted average concentration for an
8-hour period. In order to achieve compliance with this mandatory
airborne mercury level, you must implement feasible engineering or
administrative controls or maintain an effective respiratory
protection program should such controls be found infeasible. The
National Institute of Occupational Safety and Health has recommended
that the permissible exposure limit for mercury be lowered to .05
mg/M3. This recommendation is currently being considered by OSHA.
As an interim measure until such time as a complete standard is
promulgated we are forwarding herewith recommended guidelines for
protection of your employees against the risk of illness resulting
from exposure to inorganic mercury and its compounds. These
recommendations involve preventive steps of good housekeeping,
personal hygiene, medical surveillance, monitoring and measuring of
exposure levels, employee training, and respirator information which
should ensure a healthful workplace for those of your employees who
are involved in such manufacturing processes. The issuance of these
guidelines does not alter our intention to continue our compliance
activities.
The threat of mercury poisoning is ever present if mercury and its
compounds are not treated with utmost care in the manufacturing
process. Therefore, voluntary compliance with the enclosed
nonmandatory guidelines would further the overall objective of the
Occupational Safety and Health Act - to assure so far as possible,
safe and healthful working conditions.
Your cooperation in this matter is greatly appreciated. Protection
of your employees from overexposure to mercury is, I am confident,
our common goal.
Bert M. Concklin
Deputy Assistant Secretary
Guidelines for Controlling Occupational Exposure to Mercury
or Its Inorganic Compounds
In accordance with the Occupational Safety and Health
Administration's (OSHA) standard for air contaminants (29 CFR
1910.1000), employee exposure to airborne mercury or its inorganic
compounds shall not exceed an 8-hour time-weighted average limit of 1
mg/10 M3 (0.1 mg/M3) or a limit set by a state agency whenever a
state-administered Occupational Safety and Health Plan is in effect.
It should be emphasized that the permissible exposure limit is a
time-weighted average. The first mandatory requirement is that
employee exposure be eliminated through the implementation of
feasible engineering controls. After all such controls are
implemented and do not fully control to permissible exposure limits,
each employer must rotate its employees to the extent possible in
order to reduce exposure. Only when all engineering or
administrative controls have been implemented, and the level of
mercury still exceeds permissible exposure limits, may an employer
rely on a respirator program pursuant to the mandatory requirements
of 1910.134. In addition it is mandatory that no employee be allowed
to consume food or beverages in an area exposed to mercury (29 CFR
1910.141(g)(2)). Generally, where working conditions or other
practices constitute recognized hazards likely to cause death or
serious physical harm, they must be corrected pursuant to Section
5(a)(1) of the Occupational Safety and Health Act.
In addition to these mandatory requirements, the National
Institute of Occupational Safety and Health has recommended that the
limit be lowered to 0.05 mg/M3; this recommendation is currently
being considered by OSHA. Pending such consideration, the following
recommendations are made to ensure that employee exposure to mercury
and its inorganic compounds is controlled to the permissible exposure
limit.
1. MONITORING
a. Initial Evaluation
Each employer who has a place of employment in which
mercury or its inorganic compounds are occupationally
produced, reacted, released, packaged, repackaged,
transported, stored, handled, or used should inspect each
workplace and work operation to determine if any employee
may be exposed to mercury or its inorganic compounds.
Indicators that an evaluation of employee exposure should
be undertaken would include:
(i) Any information or observations which would indicate
employee exposure to mercury or its inorganic
compounds;
(ii) Any measurement of airborne mercury vapor or the dust
of its inorganic compounds;
(iii) Any employee complaints of symptoms which may be
attributable to exposure to mercury or its inorganic
compounds;
(iv) Whenever there has been a production, process, or
control change which may result in an increase in the
airborne concentration of mercury vapor or the dust
of its inorganic compounds, or whenever the employer
has any other reason to suspect an increase in the
airborne concentrations of mercury vapor or the dust
of its inorganic compounds.
b. Air Monitoring
(i) Employee exposure measurements should represent the
actual breathing zone exposure conditions for each
employee. Any appropriate combination of long-term
or short-term samples would be acceptable, but all
exposures should be calculated on an 8-hour time-weighted
average, assuming a 40-hour work week, to arrive at the
permissible exposure limit.
(ii) Accuracy of Measurement. The method of monitoring
and analysis should have an accuracy of not less than
plus or minus 20% for concentrations of airborne
mercury vapor or the dust of its inorganic compounds
equal to or greater than the permissible exposure
limit. (One method meeting this accuracy requirement
is available in the "NIOSH Manual of Analytical
Methods," Government Printing Office Stock No.
1733-00041.)
(iii) Frequency of Monitoring. Where the employer has
determined that employees are exposed to mercury or
its inorganic compounds in excess of the permissible
exposure limit, monitoring should be repeated
quarterly.
2. MEDICAL SURVEILLANCE
Each employer should institute a medical surveillance program
for all employees who are or will be exposed to airborne
concentrations of mercury vapor or the dust of its inorganic
compounds above the permissible exposure limit. The program
should provide each employee with an opportunity for biological
monitoring and medical examination performed by or under the
supervision of a licensed physician and provided during the
employee's normal working hours without cost to the employee.
a. Medical Examination
(i) Each employer should provide a medical examination
which includes a complete medical history and
physical examination, complete blood count, routine
urinalysis (specific gravity, sugar, protein
determinations, and microscopic examination), and
voluntary pregnancy test, where appropriate, to each
employee exposed to mercury or its inorganic
compounds in excess of the permissible exposure
limit.
(ii) Medical examinations should also be made available:
(a) To employees prior to their assignment to areas
in which airborne concentrations of mercury or
its inorganic compounds are above the
permissible exposure limit;
(b) At least annually for each employee exposed to
airborne concentrations of mercury or its
inorganic compounds above the permissible
exposure exposure limit at any time during the
preceding six months;
(c) For each employee whose urine analysis sampling
series indicates elemental mercury level at or
above 0.02 mg per liter of urine or total mercury
level in excess of .200 mg per liter of urine,
which is not receding;
(d) Immediately upon notification by the employee
that the employee has developed signs or
symptoms commonly associated with toxic exposure
to inorganic mercury or its compounds.
(iii) Where medical examinations are performed, the
employer should provide the examining physician with
the following information:
(a) The reason for the medical examination
requested;
(b) A description of the affected employee's duties
as they relate to the employee's exposure;
(c) A description of any personal protective
equipment used or to be used;
(d) The results of the employee's exposure
measurements, if available;
(e) The employee's anticipated or estimated exposure
level;
(f) The results of the employee's biological
monitoring; and
(g) Upon request of the physician, information
concerning previous medical examination of the
affected employee.
b. Biological Monitoring
(i) Urine sampling and analysis should be the biological
monitoring method used. The method of analysis for
total, ionic and elemental mercury in urine is
described in the American Industrial Hygiene
Association Journal, September 1974, pp. 576-580.
For the analysis at least 100 ml of urine should be
collected during a work day when sampling is
scheduled.
(ii) Accuracy of Measurement. Sample analysis should have
an accuracy to a confidence level of 95% as it
pertains to the repeatability of several analyses
from any given urine sample.
(iii) Frequency of Monitoring
(a) If possible, a urine sample should be obtained
of all employees who will be assigned to work
with mercury or its inorganic compounds prior to
exposure to the work area.
(b) For employees exposed to less than permissible
levels of airborne mercury, urine sampling and
analysis should be done every six months.
(c) For employees exposed to airborne mercury vapor
or inorganic mercury compounds above the
permissible exposure limit, urine sampling and
analysis should be performed every three months
for each employee. It should continue at least
six months after the last known exposure above
the permissible exposure limit if the employee
is available for sampling.
(d) Where the total mercury level exceeds .200 mg of
mercury per liter of urine, or 0.02 mg of
elemental mercury per liter of urine, sampling
should be accelerated to a weekly basis. The
activities of the employees should be observed
to detect the potential source of mercury
intake.
(e) If the total mercury level in urine does not
decrease during the one month sampling period,
or if the elemental mercury level in urine does
not decrease in two weeks, a physician should be
consulted.
(iv) (a) The results of employee urine sampling should
also be considered as a group exposure by area
of assignment and/or by job description.
Elevated group urine mercury levels should be a
cause for review of operational practices,
process controls, and a change in either or both
to reduce employee exposures.
(b) If several employee urine samples from the same
area of assignment indicate excessive elemental
mercury urine levels, corrective action in the
area should be started by the employer
immediately.
c. Physician's Written Opinion
(i) The employer should obtain and furnish the employee
with a written opinion from the examining physician
containing the following:
(a) The signs or symptoms of mercury exposure
manifested by the employee, if any;
(b) A laboratory report of the mercury content in
blood or urine if such analysis is performed by
or under the supervision of the physician, or
reported to the physician by a laboratory to
which such samples have been submitted for
analysis;
(c) The physician's opinion as to whether the
employee has any detected risk of material
impairment to the employee's health from
exposure to mercury or its inorganic compounds
or would directly or indirectly aggravate any
detected medical condition;
(d) Any recommended limitation upon the employee's
exposure to mercury or its inorganic compounds
or upon the use of personal protective equipment
and respirators; and
(e) A statement that the employee has been informed
by the physician of any medical condition which
requires further examination or treatment.
(ii) The written opinion obtained by the employer should
not reveal specific findings or diagnoses unrelated
to occupational exposure to mercury or its inorganic
compounds.
(iii) If the employer determines, on the basis of the
physician's written opinion, that any employee's
health would be materially impaired by maintaining
the existing exposure to mercury or its inorganic
compounds, the employer should place specific
limitations, based on the physician's written
opinion, on the employee's continued exposure to
mercury or its inorganic compounds.
3. TRAINING
a. Each employer who has a workplace in which elemental
mercury or its inorganic compounds are stored and used
occasionally in small quantities, and where airborne mists,
fumes, vapors, or dusts may be accidentally or
intentionally produced and released in the work environment
due to handling, storage, or use should:
(i) Inform employees who work or will be working with
mercury or its inorganic compounds occasionally of
potential health hazards;
(ii) Inform employees of the correct work and storage
practices, written emergency procedures to be
followed in case of spills or leaks, and personal
protective equipment necessary in emergencies;
(iii) Provide equipment and/or materials necessary to
control mercury-containing spills or leaks in
quantity sufficient to control the entire amount of
mercury or compound used;
(iv) Provide written procedures and means for removal of
mercury or its compounds from body surfaces and
working surfaces, machinery, or tools to be used
later for other work activities;
(v) Establish limited areas within the workplace where
mercury or its compounds can be used;
(vi) Inform and local fire department of the exact
location of storage and the hazards in case of fire;
(vii) Assure that the permissible exposure limit is not
exceeded in the work environment during the
occasional uses.
b. A training program for all new employees prior to work
assignment and for all affected employees at least annually
should be provided by employers:
(i) Who have a workplace in which mercury metal, its
vapors, fumes, solutions, or inorganic mercury
compound dusts, mists, solutions or vapors are
routinely produced, reacted, used, stored, handled in
the open work environment, and where the possibility
of exceeding the permissible exposure limit exists;
or
(ii) Whose employees may have the opportunity for routine
significant contacts with mercury metal or its
inorganic compounds as solutions, dusts, or mists
because such materials are the ingredients or
byproducts of a handling, use, or production process.
c. The training program should:
(i) Advise affected employees of the signs and symptoms
of over-exposure to mercury;
(ii) Instruct affected employees to advise the employer
of the development of the signs and symptoms of
overexposure to mercury;
(iii) Inform employees of the specific nature of
operations which could result in exposure to mercury
above the permissible exposure limit, as well as
safe work practices for the handling, use, release,
storage, or disposal of the mercury or its compounds
in normal operations;
(iv) Instruct employees in proper housekeeping practices,
decontamination procedures in the event of a mercury
or mercury compound spill, and fire emergency
procedures;
(v) Emphasize the possibility of ingesting mercury by
hand-to-mouth contact when good personal hygiene is
not practiced;
(vi) Inform employees of measures necessary to protect
them from exposures in excess of the permissible
exposure limit. The wearing and turning-in of
protective clothing should be stressed;
(vii) Instruct employees as to the purpose, proper use,
and limitations of respirators;
(viii) Provide employees with a description of, and explain
the purposes for, the medical surveillance program;
(ix) Inform employees where written procedures and hazard
information are available on the premises.
4. PERSONAL PROTECTIVE EQUIPMENT
a. Where respirators are required under 1910.1000(e) and
1910.134, the employer should select and provide an
appropriate respirator from the table below.
b. Recommendations for Respirator Usage at Mercury
Concentrations Above Permissible Exposure Limit
-----------------------------------------------------------
| Airborne Concentration | |
| of Mercury | Recommended Respirator |
-----------------------------------------------------------
| 1. Fume, dust, vapor | (A) A type C supplied-air |
| or mist in excess | respirator with a full |
| of 5 mg/M3 | facepiece operated in |
| | pressure-demand or other |
| | positive pressure mode, |
| | or |
| | (B) A self-contained breathing|
| | apparatus with a full |
| | facepiece operated in |
| | pressure-demand or other |
| | positive pressure mode. |
| | |
| 2. Fume, dust, vapor | (A) A type C supplied-air |
| or mist less than | respirator with a full |
| 5 mg/M3 | facepiece operated in |
| | pressure-demand or other |
| | positive pressure mode, |
| | or |
| | (B) A self-contained breathing|
| | apparatus with a full |
| | facepiece operated in |
| | pressure-demand or other |
| | positive pressure mode, |
| | or |
| | (C) Cartridge type respirator,|
| | when approved (TC) and |
| | available. |
-----------------------------------------------------------
c. Only those respiratory protection devices which have been
approved by the National Institute of Occupational Safety
and Health under the provisions of 30 CFR Part 11 should be
used.
d. There should be an established in-plant procedure and means
and facilities provided to issue respiratory protective
equipment, to return used contaminated equipment, to
decontaminate and disinfect the equipment, and to repair or
exchange damaged equipment. Record keeping of these
activities should be considered, especially on recharge of
self-contained breathing apparatus air cylinders.
5. PROTECTIVE CLOTHING
a. Where protective clothing is required under 1910.132, the
employer should provide and ensure that employees wear
appropriate, clean, protective clothing, such as, but not
limited to, coveralls, smocks, aprons, gloves, shoes, hair
covers or hats, in the following situations:
(i) Where employees may be exposed to concentrations of
mercury above the permissible exposure limit; or
(ii) Where the skin, hair, or clothing of employees may
have repeated contact with accumulations of mercury
fume, dust, mist, or solutions.
b. The employer should launder, maintain, and/or dispose of
all contaminated personal clothing discarded by employees.
c. The removal of mercury fume or dust from protective
clothing by blowing or shaking should be prohibited.
d. The employer should ensure that all protective clothing is
removed in change rooms and deposited in marked laundry
bags.
e. The employer should inform any person who launders or
cleans mercury-contaminated protective clothing of the
potentially harmful effects of exposure to mercury and of
precautions to take, such as not airing or shaking the
clothing to remove mercury fume or dust.
f. Street clothing and street footwear should not be permitted
in the workplace whenever airborne mercury concentrations
exceed the permissible exposure limit or potential contacts
with mercury or its inorganic compounds exist.
Contaminated clothing or footwear should not leave the
plant except in packages for laundering, decontamination,
or disposal.
g. Employees who work with elemental mercury should turn in
all protective clothing used after each shift of use.
h. If protective clothing and plant footwear is provided for a
longer period of use, they should be stored separately from
personal street clothing, street footwear, food, tobacco
products, and other personal effects.
6. HOUSEKEEPING
a. All exposed surfaces should be maintained free of
accumulation of mercury which, if dispersed, would result
in airborne concentrations in excess of the permissible
exposure limit or in a visible dust cloud.
b. Dry sweeping and the use of compressed air for the cleaning
of floors and other surfaces should be prohibited. If
vacuuming is used, the exhaust air should be properly
filtered to prevent generation of airborne mercury
concentrations.
c. Persons not wearing respiratory protective equipment should
be excluded from areas where spills or leaks of mercury or
inorganic mercury compounds have occurred until cleanup has
been completed.
d. All hand contact points (such as tools, door knobs, table
tops, etc.) should be maintained free of mercury
contamination. If this is impossible, gloves should be
provided.
e. Carpeting should not be used anywhere within the workplace.
Doormats should be treated as mercury-contaminated objects.
f. Used industrial wipe rags, floor cleaning mops, or paper
towels used on mercury contaminated surfaces should be
treated as potentially contaminated. They should not be
rehandled, reused, compressed and stuffed, or dried on
in-plant uncontrolled heaters.
7. PERSONAL HYGIENE FACILITIES AND PRACTICES
a. All food, beverages, tobacco products, nonfood chewing
products, and unapplied cosmetics should be prohibited in
areas where there is a likelihood that skin or clothing may
come in contact with fume, dust, mist, or solutions of
mercury or where the airborne concentrations of mercury
are above the permissible exposure limit. See the
mandatory portion (page 1) of this Guideline.
b. The employer should ensure that employees or visitors who
work in or need access to areas specified in paragraph 5.a.
wash their hands, forearms, face, and neck before each
occasion of eating, drinking, smoking, or applying
cosmetics and at the end of each work shift. All other
employees should be encouraged in this practice.
c. Employers should provide an adequate number of lavatories,
maintained and provided with soap, hand brushes, and
towels. Employees should be instructed in using the
handbrushes on fingernails submerged in washwater. Used
paper or fabric towels should be considered and treated as
contaminated.
d. Where employees wear protective clothing or equipment, or
both, change rooms shall be provided in accordance with
1910.141(e).
e. Rings, watches, wallets, combs, and other personal items
usually carried on a person should not be brought in
contact with mercury or its compounds if at all possible.
The frames of safety glasses or personal glasses should be
carefully cleaned after each shift of work.
f. Contact lenses should not be used in areas where eyes may
be exposed to vapors, dusts, or mists containing mercury.