California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 4 - Construction Safety Orders › Article 4 - Dusts, Fumes, Mists, Vapors, and Gases › Appendix C to Section 1532.1 - Medical Surveillance Requirements

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
This appendix outlines the medical surveillance
						provisions of the construction standard for lead and provides further
						information to the physician or other licensed health care professional (PLHCP)
						regarding the examination and evaluation of employees exposed to lead.
Introduction
The primary purpose of the Occupational Safety and Health
						Act of 1970 is to ensure, so far as possible, safe and healthful working
						conditions for every working person. The occupational health standard for lead
						in construction is designed to protect employees exposed to inorganic lead
						including metallic lead, all inorganic lead compounds and organic lead
						soaps.
Under this standard occupational exposure to inorganic
						lead is to be limited to 10 µg/m3 (micrograms
						per cubic meter) calculated as an 8-hour time-weighted average (TWA). This
						permissible exposure limit (PEL) must be achieved through a combination of
						engineering, work practice and administrative controls to the extent feasible.
						Where these controls are in place but are found not to reduce employee
						exposures to or below the PEL, they must be used nonetheless, and supplemented
						with respirators to meet the 10 µg/m3 exposure
						limit. As an exception, until January 1, 2030, the PEL for employees conducting
						abrasive blasting is 25 µg/m3, calculated as
						an 8-hour TWA.
The standard establishes an action level of 2
						µg/m3 calculated as an 8-hour TWA. The action
						level refers to employee exposure, without regard to the use of respirators.
						The action level triggers several ancillary provisions of the standard such as
						exposure monitoring, medical surveillance, a training program, and
						signs.
The standard lists certain construction tasks which, when
						lead is present, may likely result in exposures to lead in excess of the PEL
						and, in some cases, exposures in excess of 50 times the PEL. These tasks are
						known as trigger tasks, and are described in subsection (d)(2) of the lead
						standard. Trigger tasks are categorized as level 1, level 2, or level 3 trigger
						tasks. Performing level 3 trigger tasks is presumed to result in the highest
						exposures to lead. Level 1 trigger tasks include manual demolition of
						structures (such as dry wall), manual scraping, and heat gun applications.
						Level 2 trigger tasks include manual sanding, power tool cleaning, grinding, or
						sanding with dust collection systems, and spray painting with lead paint. Level
						3 trigger tasks include using lead-containing mortar or lead burning, and rivet
						busting, power tool cleaning, grinding or sanding without dust collection
						systems, cleanup activities where dry expendable abrasives are used, abrasive
						blasting enclosure movement and removal, abrasive blasting, welding, torch
						cutting, and torch burning. If an employee performs any of these trigger tasks
						when lead is present, or if the employer has any reason to believe that the
						employee may be exposed to lead over the PEL, the employer must provide the
						employee with interim protection, until such time that an exposure assessment
						is conducted which demonstrates that the employee's exposure level to lead is
						below the PEL. Interim protections include appropriate respiratory protection,
						protective clothing and equipment, change areas, shower facilities (for level 3
						trigger tasks), eating areas, regulated areas, and medical surveillance.
The standard also provides for a program of medical
						surveillance for employees, as outlined in section I of this Appendix. This
						program consists of initial blood lead testing and medical evaluation, along
						with periodic blood lead testing and medical evaluation, to be performed on a
						schedule which is defined by previous laboratory results, employee complaints
						or concerns, and the clinical assessment of the examining PLHCP.
Section I provides a detailed description of the medical
						surveillance procedures including the required frequency of blood lead testing
						and medical examination and consultation for exposed employees, provisions for
						medical removal protection (MRP), the right of the employee to a second medical
						opinion, and notification and recordkeeping requirements of the PLHCP and the
						employer. A discussion of the requirements for respirator use and respirator
						monitoring and Cal/OSHA's position on prophylactic chelation therapy are also
						included in this section.
Section II discusses the toxic effects and clinical
						manifestations of lead poisoning and effects of lead intoxication on the
						cardiovascular, neurologic, renal, gastrointestinal and hematologic systems.
						The adverse effects on both male and female reproductive capacity and on the
						fetus are also discussed.
Section III outlines the recommended medical evaluation
						of the employee exposed to inorganic lead, including details of the medical
						history, physical examination, and recommended laboratory tests, which are
						based on the toxic effects of lead as discussed in section II.
Section IV provides detailed information concerning the
						laboratory tests available for the monitoring of exposed employees. Included
						also is a discussion of the relative value of each test and the limitations and
						precautions which are necessary in the interpretation of the laboratory
						results.
I. Medical Surveillance Requirements for Employees
						Exposed to Inorganic Lead
A. Blood Lead Testing
Under the standard for inorganic lead in the construction
						industry, initial blood lead testing shall be provided to employees prior to
						assignment to work where exposure to lead is or is likely to be at or above the
						action level. There are three exceptions to this requirement. The first
						exception is if the employee is not, and is not reasonably expected to be,
						exposed to lead at or above the action level for 30 or more days in any 12
						consecutive months, and is not exposed on any day above 10
						µg/m3 as an 8-hour TWA, without regard to
						respirator use, then initial blood lead testing is not required to be provided.
						The second exception is if the employee is not, and is not reasonably expected
						to be, exposed to lead at or above the action level for 15 or more days in any
						12 consecutive months, and is not exposed on any day above 20
						µg/m3 as an 8-hour TWA, without regard to
						respirator use, then initial blood lead testing is not required to be
						provided.The third exception is if the employee had a blood lead test in the
						preceding two months, then initial blood lead testing is not required to be
						provided.
Initial blood lead testing shall also be provided to
						employees as interim protection, unless a negative initial determination has
						been made, prior to performing trigger tasks described in subsection (d)(2) of
						the lead standard.
After the initial blood lead testing, additional blood
						lead testing must be made available to employees. There are three exceptions to
						this requirement. The first exception is if an employee is not exposed to lead
						at or above the action level for 30 or more days in any 12 consecutive months,
						and their exposure is not on any day above 10
						µg/m3 as an 8-hour TWA, without regard to
						respirator use, then additional blood lead testing is not required to be
						provided. The second exception is if an employee is not exposed to lead at or
						above the action level for 15 or more days in any 12 consecutive months, and
						their exposure is not on any day above 20
						µg/m3 as an 8-hour TWA, without regard to
						respirator use, then additional blood lead testing is not required to be
						provided. The third exception is if they only perform level 1 trigger tasks,
						and perform these level 1 trigger tasks on less than 10 days in any 12
						consecutive months, then additional blood lead testing is not required to be
						provided. Also, if the employee's initial blood lead level (BLL) is at or above
						10 µg/dl, they must be provided with additional blood lead testing, as
						described in the next paragraph. There are no exceptions to this.
Unless an employee's exposure to lead or work with lead
						falls under one the exceptions described above, blood lead testing under the
						standard must be provided on the following schedule: at least every two months
						for the first six months after initial placement, and also for the six months
						after any change in task resulting in higher exposure; and every six months
						thereafter. If an employee's last BLL is at or above 10 µg/dl but is
						below 20 µg/dl, the testing frequency must be at least every two months.
						This frequency must continue until two consecutive BLLs, taken at least 30 days
						apart, are less than 10 µg/dl. Blood lead testing then must be provided
						as described in the schedule given at the start of this paragraph. For
						employees whose last blood lead test indicated a BLL at or above 20 µg/dl
						or who are removed from exposure to lead due to an elevated blood lead, a new
						BLL must be measured monthly. Monthly blood lead tests must also be provided as
						an interim protection for each employee who performs a level 3 trigger task as
						listed in subsection (d)(2)(D), including a blood test taken within 3 days
						after discontinuing all level 3 trigger task work. Finally, blood lead tests
						must be provided at least monthly to each employee whose airborne exposure to
						lead is above 500 µg/m3 as an 8-hour TWA,
						without regard to the use of respirators, including a blood test taken within 3
						days after discontinuing all work associated with airborne exposure above 500
						µg/m3 as an 8-hour TWA.
B. Medical Examination and Consultation
An initial medical examination and consultation performed
						under the guidelines discussed in section III is to be made available to an
						employee where exposure to lead will be at or above the action level, and as
						interim protection prior to performing trigger tasks. There are three
						exceptions to this requirement. The first exception is if an employee is not
						exposed to lead at or above the action level for 30 or more days in any 12
						consecutive months, and their exposure is not on any day above 10
						µg/m3 as an 8-hour TWA, without regard to
						respirator use, then a medical examination is not required to be provided. The
						second exception is if an employee is not exposed to lead at or above the
						action level for 15 or more days in any 12 consecutive months, and their
						exposure is not on any day above 20 µg/m3 as
						an 8-hour TWA, without regard to respirator use, then a medical examination is
						not required to be provided. The third exception is if an employee only
						performs level 1 trigger tasks, and they perform these level 1 trigger tasks on
						less than 10 days in any 12 consecutive months, then a medical evaluation is
						not required to be provided.
Medical examinations must be made available prior to
						assignment to lead work. There is an exception to this requirement. A medical
						examination is not required prior to assignment if an employee had a
						lead-specific medical examination in the preceding two months. Medical
						examinations beyond the initial one must be made available on an annual basis
						if an employee's BLL is 20 µg/dl or greater at any time during the
						preceding year. This medical examination must be made available as soon as
						possible upon receiving a blood lead test result of 20 µg/dl or greater
						if the employee has not had a lead-specific medical examination in the last 12
						months. In addition, a medical examination must be provided as soon as possible
						after notification by an employee that the employee has developed signs and
						symptoms commonly associated with lead intoxication, that the employee desires
						medical advice regarding lead exposure and the ability to procreate a healthy
						child, or that the employee has demonstrated difficulty in breathing during a
						respirator fit test or during respirator use. A medical examination beyond the
						initial one is also to be made available to each employee removed from exposure
						to lead due to an elevated blood lead level, as discussed in the next section,
						or otherwise limited or specially protected pursuant to medical
						recommendations.
The requirements of section
						1532.1 for the medical surveillance
						of employees who are exposed to lead are summarized in Table 1.Table 1. Minimum
						Requirements for Medical Surveillance.
A.
Initial blood lead level (BLL) test
								required to be made available.
Prior to assignment to work
								where exposure to lead is or reasonably expected to be >= the action level
								(2 µg/m3 as an 8-hour TWA); and
NOTE: initial blood lead
								testing is not required for an employee who:
is not, and is not
								reasonably expected to be, exposed to lead >= the action level for >= 30
								days in any 12 consecutive months, and is not exposed on any day above 10
								µg/m3 as an 8-hour TWA; or
is not, and is not
								reasonably expected to be, exposed to lead >= the action level for >= 15
								days in any 12 consecutive months, and is not exposed on any day above 20
								µg/m3 as an 8-hour TWA; or
has had a blood lead
								test in the preceding two months.
Prior to performing
								trigger tasks, and an exposure assessment has not been completed.
B.
Additional BLL tests
								required to be made available.
For employees:
>whose last BLL
								was >= 10 µg/dl; or
who are exposed
								>= action level; or
NOTE: additional
								blood lead tests are not required for an employee who:
is not exposed to lead
								>= the action level for >= 30 days in any 12 consecutive months, and is
								not exposed on any day above 10 µg/m3 as an
								8-hour TWA; or
is not exposed to
								lead >= the action level for >= 15 days in any 12 consecutive months, and
								is not exposed on any day above 20 µg/m3 as an
								8-hour TWA.
who perform trigger
								tasks, and an exposure assessment has not been completed.
NOTE: additional blood
								lead tests are not required for an employee who:
only performs level 1
								trigger tasks and who performs these level 1 trigger tasks on < 10 days in
								any 12 consecutive months, unless their last BLL was >= 10 µg/dl.
C.
Schedule of BLL tests required to be
								made available for employees when their:
1. Last BLL was < 10 µg/dl,
								and the employee is included in B above.
Every 2 months for
								the first 6 months after initial placement, and also for the first 6 months
								after a change in task resulting in higher exposure, and then every 6
								months.
2. Last BLL was >= 10 µg/dl
								but < 20 µg/dl.
Every 2 months. Continue until 2
								BLLs, taken at least 30 days apart, are < 10 µg/dl.
3. Last BLL was >= 20
								µg/dl.
Every 1 month.
D.
Schedule of BLL tests required to be
								made available for employees whose airborne exposure is above 500
								µg/m3 as an 8-hour TWA.
Every 1 month. Include a blood test taken within 3 days after
								discontinuing all work associated with airborne exposure> 500
								µg/m3 as an 8-hour TWA.
E.
Schedule of BLL tests required to be
								made available for employees who perform a level 3 trigger task, and an
								exposure assessment has not been completed.
Every 1 month.
								Include a blood test taken within 3 days after discontinuing all level 3
								trigger task work.
F.
Initial medical examination and
								consultation required to be made available.
Prior to
								assignment for employees who will be:
exposed >=
								action level; or
NOTE: medical
								examination and consultation prior to assignment is not required for an
								employee who:
is not exposed to
								lead >= the action level for >= 30 days in any 12 consecutive months, and
								is not exposed on any day above 10 µg/m3 as an
								8-hour TWA; or
is not exposed to
								lead >= the action level for >= 15 days in any 12 consecutive months, and
								is not exposed on any day above 20 µg/m3 as an
								8-hour TWA.
performing trigger
								tasks, and an exposure assessment has not been completed.
NOTE: medical
								examination and consultation prior to assignment is not required for an
								employee who:
only performs level 1
								trigger tasks and who performs these level 1 trigger tasks on < 10 days in
								any 12 consecutive months.
Additionally, medical
								examinations are not required prior to assignment if an employee had a
								lead-specific medical examination in the preceding two months.
G.
Additional medical examinations and
								consultations required to be made available.
For employees
								who are:
exposed >=
								action level; or
NOTE: medical
								examination and consultation is not required for an employee who:
is not exposed to
								lead >= the action level for >= 30 days in any 12 consecutive months, and
								is not exposed on any day above 10 µg/m3 as an
								8-hour TWA; or
is not exposed to
								lead >= the action level for >= 15 days in any 12 consecutive months, and
								is not exposed on any day above 20 µg/m3 as an
								8-hour TWA.
performing trigger
								tasks, and an exposure assessment has not been completed.
NOTE: medical
								examination and consultation is not required for an employee who:
only performs level 1
								trigger tasks and who performs these level 1 trigger tasks on < 10 days in
								any 12 consecutive months.
H.
Schedule of additional medical
								examinations and consultations required to be made available, for employees
								included in G above.
As soon as possible when an employee's
								BLL is >= 20 µg/dl, if no lead-specific medical examination was done
								in the preceding 12 months; and
annually until the
								employee's BLL is < 20 µg/dl.
As soon as
								possible, upon notification by an employee either that the employee has
								developed signs or symptoms commonly associated with lead intoxication, that
								the employee desires medical advice concerning the effects of current or past
								exposure to lead on the employee's ability to procreate a healthy child, that
								the employee is pregnant, or that the employee has demonstrated difficulty in
								breathing during a respirator fit test or during use.
[Note: Exposure levels in Table 1 are without regard to
						an employee's use of a respirator.]
C. Medical Removal Protection
Results of BLL testing or the recommendations of an
						examining PLHCP may necessitate removal of an employee from further lead
						exposure pursuant to the standard's medical removal protection (MRP) program.
						The object of the MRP program is to provide temporary medical removal to
						employees either with substantially elevated BLLs or otherwise at risk of
						sustaining material health impairment from continued substantial exposure to
						lead.
Under the standard's employee medical removal criteria,
						an employee is to be removed from any work having an exposure to lead at or
						above the action level, involving a trigger task as listed in subsection (d)(2)
						of the lead standard, or altering or disturbing any material containing lead at
						a concentration equal to or greater than 0.5% by weight, on each occasion
						that:
1. The last blood lead test indicates that the employee's
						BLL is at or above 30 µg/dl; or
2. Effective January 1, 2026, the last two blood lead
						test results are at or above 20 µg/dl; or
3. Effective January 1, 2026, the average of the results
						of all blood lead tests conducted in the last 6 months is at or above 20
						µg/dl, unless the last blood test indicates a blood lead level below 15
						µg/dl, in which case the employee need not be removed.
Medical removal is to continue until two consecutive
						BLLs, taken at least 30 days apart, are below 15 µg/dl.
In addition to the above BLL criteria, temporary medical
						removal for employees may also take place as a result of medical determinations
						and recommendations. A written medical opinion must be prepared after each
						examination pursuant to the standard. If the examining PLHCP includes a medical
						finding, determination or opinion that the employee has a health-related
						condition which places the employee's health, including the ability to
						procreate a healthy child, at increased risk of material impairment from
						exposure to lead, then the employee must be removed from work having an
						exposure to lead at or above the action level, involving a trigger task as
						listed in subsection (d)(2) of the lead standard, or altering or disturbing any
						material containing lead at a concentration equal to or greater than 0.5% by
						weight. Alternatively, if the examining PLHCP recommends special protective
						measures for an employee (e.g., use of a powered air purifying respirator) or
						recommends limitations on an employee's exposure to lead, then the employer
						must implement these recommendations.
Monthly BLL tests must be made available during the
						medical removal period for an employee who is removed from exposure to lead due
						to an elevated BLL. In addition, unless an employee's exposure or work is
						covered by the exceptions described in subsection I.B. of this appendix, a
						medical examination is to be made available as soon as possible and then as
						medically appropriate to each employee removed from exposure to lead due to an
						elevated BLL or due to a risk of sustaining material impairment to health, or
						otherwise limited or specially protected pursuant to medical
						recommendations.
Recommendations may be more stringent than the specific
						provisions of the standard. The examining PLHCP, therefore, is given broad
						flexibility to tailor special protective procedures to the needs of individual
						employees. This flexibility extends to the evaluation and management of
						pregnant employees and employees who are planning to raise children. Based on
						the history, physical examination, and laboratory studies, the PLHCP might
						recommend special protective measures or medical removal for an employee who is
						pregnant or who is planning to conceive a child when, in the PLHCP's judgment,
						continued exposure to lead at the current job would pose a significant risk.
						The return of the employee to their former job status, or the removal of
						special protections or limitations, depends upon the examining PLHCP
						determining that the employee is no longer at increased risk of material
						impairment or that special measures are no longer needed.
During the period of any form of special protection or
						removal, the employer must maintain the employee's earnings, seniority, and
						other employment rights and benefits (as though the employee had not been
						removed) for a period of up to 18 months or for as long as the job the employee
						was removed from lasts if less than 18 months. This economic protection will
						maximize meaningful employee participation in the medical surveillance program,
						and is appropriate as part of the employer's overall obligation to provide a
						safe and healthful workplace. The provisions of MRP benefits during the
						employee's removal period may, however, be conditioned upon participation in
						medical surveillance.
The requirements of section
						1532.1 for the temporary removal of
						an exposed employee and their subsequent return to work with lead are
						summarized in Table 2.Table 2. Minimum Requirements During the Medical Removal
						Protection (MRP) Period.
A.
BLL requiring employee medical
								removal.
one BLL >= 30 µg/dl; or
effective January 1, 2026, the
								last two BLLs are >= 20 µg/dl; or
effective January 1, 2026, the
								average of all BLLs over the last 6 months is >= 20 µg/dl, unless the
								last blood test indicates a blood lead level below 15 µg/dl, in which
								case the employee need not be removed.
B.
MRP due to a final medical
								determination.
A written medical opinion on the employee's health
								status by the examining PLHCP results in a medical finding, determination, or
								opinion that the employee has a detected health-related condition which places
								the employee's health, including the ability to procreate a healthy child, at
								increased risk of material impairment from exposure to lead.
C.
Frequency of BLL tests required to be
								made available for an employee removed from exposure to lead because of an
								elevated BLL.
Every 1 month.
D.
Medical examinations and consultations
								required to be made available.
As soon as possible, then as medically
								appropriate, for an employee:
removed from exposure to lead
								due to elevated blood lead levels, or
whose exposure to lead is
								otherwise limited pursuant to a final medical determination.
E.
Permissible working conditions for an
								employee on MRP.
Employee must be removed from any work:
having an exposure to lead
								(without regard to respirator use) >= the action level; or
involving a trigger task;
								or
altering or disturbing any
								material containing lead at a concentration >= 0.5% by weight.
F.
When an employee has been placed on MRP
								due to elevated BLL, the BLL at which an employee shall be returned to their
								former work.
Two consecutive BLLs, taken at least 30 days apart, both
								indicate a BLL < 15 µg/dl.
G.
When an employee has been placed on MRP
								due to a final medical determination, the conditions under which an employee
								shall be returned to their former work.
A subsequent final medical
								determination results in a medical finding, determination, or opinion that the
								employee no longer has a detected health-related condition that places the
								employee's health, including the ability to procreate a healthy child, at
								increased risk of material impairment from exposure to lead.
Note: When a medical opinion indicates that an employee
						is at risk of material impairment from exposure to lead, the PLHCP can remove
						an employee from exposures exceeding the action level (or less) or recommend
						special protective measures as deemed appropriate and necessary. Medical
						monitoring during the medical removal period can be more stringent than noted
						in the table above if the PLHCP so specifies. Return to work or removal of
						limitations and special protection is permitted when the PLHCP indicates that
						the employee is no longer at risk of material impairment.
The lead standard provides for a multiple PLHCP review in
						cases where the employee wishes a second opinion concerning potential lead
						poisoning or toxicity. If an employee wishes a second opinion, they can make an
						appointment with a PLHCP of their choice. This second PLHCP will review the
						findings, recommendations or determinations of the first PLHCP and conduct any
						examinations, consultations or tests deemed necessary in an attempt to make a
						final medical determination. If the first and second PLHCPs do not agree in
						their assessment they must try to resolve their differences. If they cannot
						reach an agreement then they must designate a third PLHCP to resolve the
						dispute.
D. Requirements for Providing Information to
						Laboratories, Employees, Employers, and PLHCPs
For Blood Lead Tests:
The employer must instruct the PLHCP who orders blood
						lead tests to provide the analyzing laboratory with complete employee
						identification information. This information includes:
1. Employee name, date of birth, address, and phone
						number; and
2. Employer name, address, and phone number.
The employer must ensure that the ordering PLHCP explains
						the findings of any blood lead test and notifies the employee of the
						following:
1. The results of the blood lead test;
2. Any recommended follow-up blood lead testing in
						accordance with subsection (j)(2)(A) and the timing of that recommended blood
						lead testing; and
3. If the employee's blood lead level is 20 µg/dl
						or greater, the recommendation that the employee undergo a medical examination
						by a PLHCP if the employee has not had a lead-specific medical exam in the
						preceding 12 months.
In addition, the employer is required to provide a
						written notification to the employee within five working days after the receipt
						of the employee's blood lead test results. The employer must notify each
						employee:
1. Of that employee's BLL;
2. That the standard requires the employer to make
						medical examinations and consultations available to employees exposed at or
						above the action level, and as interim protection, to employees performing
						trigger tasks, unless an employee's exposure or work is covered by the
						exceptions in 1532.1(j)(1)(B). When they are required, the employer must make
						medical examinations and consultations available as soon as possible, upon
						notification by an employee either that the employee has developed signs or
						symptoms commonly associated with lead intoxication, that the employee desires
						medical advice concerning the effects of current or past exposure to lead on
						the employee's ability to procreate a healthy child, or that the employee has
						demonstrated difficulty breathing during a respirator fit test or during use;
						and
3. That the standard requires medical removal with MRP
						benefits when an employee's BLL exceeds any of the limits defined for medical
						removal.
For Medical Examination and Consultation:
The employer must provide examining and consulting PLHCPs
						with the following specific information:
1. A copy of the lead regulations and all
						appendices;
2. A description of the employee's duties as related to
						exposure;
3. The exposure level or anticipated level to lead and
						any other toxic substances (if applicable);
4. A description of personal protective equipment
						used;
5. Prior BLLs;
6. All prior written medical opinions regarding the
						employee in the employer's possession or control; and
7. A copy of the employer's written elevated blood lead
						level response plan (required when an employee's BLL is at or above 10
						µg/dl).
The employer must ensure that the PLHCP explains to the
						employee the results of the medical examination and provides each employee with
						a written medical report within 30 days of each medical examination performed.
						The written report shall contain:
1. The PLHCP's opinion as to whether the employee has any
						detected health-related condition that would place the employee's health,
						including the ability to procreate a healthy child, at increased risk of
						material impairment from exposure to lead;
2. Any recommended special protective measures to be
						provided to the employee, or recommended limitations to be placed upon the
						employee's exposure to lead;
3. Any recommended limitations upon the employee's use of
						respirators, including a determination of whether the employee should wear a
						powered air-purifying respirator (PAPR) instead of a non-powered air-purifying
						respirator;
4. The employee's BLL;
5. Any recommended follow-up blood lead testing and
						medical examinations and the timing of each; and
6. The PLHCP's opinion as to whether the employee has any
						health-related condition, occupational or non-occupational, that dictates
						further medical examination or treatment.
The employer must also obtain a written medical opinion
						from the examining PLHCP within 30 days of the medical examination. The written
						opinion shall contain the following information:
1. The PLHCP's opinion as to whether the employee has any
						detected health-related condition that would place the employee's health,
						including the ability to procreate a healthy child, at increased risk of
						material impairment from exposure to lead;
2. Any recommended special protective measures to be
						provided to the employee, or limitations to be placed upon the employee's
						exposure to lead;
3. Any recommended limitation upon the employee's use of
						respirators, including a determination of whether the employee can wear a PAPR
						if the PLHCP determines that the employee cannot wear a negative pressure
						respirator;
4. The employee's BLL; and
5. Any recommended follow-up blood lead testing and
						medical examinations and the timing of each.
Employers must instruct each PLHCP not to reveal to the
						employer in writing or in any other way their findings, laboratory results, or
						diagnoses which are felt to be unrelated to occupational lead exposure.
E. Additional
						Requirements
The standard provides for the use of respirators where
						engineering and other primary controls do not provide adequate protection.
						However, the use of respiratory protection shall not be used in lieu of
						temporary medical removal due to elevated BLLs or findings that an employee is
						at risk of material health impairment. This is based on the numerous
						inadequacies of respirators including skin rash where the facepiece makes
						contact with the skin, unacceptable stress to breathing in some employees with
						underlying cardiopulmonary impairment, difficulty in providing adequate fit,
						the tendency for respirators to create additional hazards by interfering with
						vision, hearing, and mobility, and the difficulties of assuring the maximum
						effectiveness of a complicated work practice program involving respirators.
						Respirators do, however, serve a useful function where engineering and work
						practice controls are inadequate by providing supplementary, interim, or
						short-term protection, provided they are properly selected for the environment
						in which the employee will be working, properly fitted to the employee,
						maintained and cleaned periodically, and worn by the employee when required. If
						the employer selects filtering facepiece respirators for protection against
						lead, they shall be N100, R100, or P100. Also, a PAPR is much more protective
						than a typical negative pressure respirator, and may also be more comfortable
						to wear. The standard provides that an employer must provide a PAPR to an
						employee upon request.
Prophylactic chelation is prohibited by the lead
						standard. Diagnostic and therapeutic chelation are permitted only when done by
						a PLHCP with appropriate medical monitoring in an acceptable clinical setting.
						The decision to initiate chelation therapy must be made on an individual basis
						and take into account the severity of symptoms felt to be a result of lead
						toxicity along with BLLs, zinc protoporphyrin (ZPP) levels, and other
						laboratory tests as appropriate. Calcium disodium EDTA (Ca Na2 EDTA) and
						succimer, which are the primary chelating agents used in the therapy of
						occupational lead poisoning, have significant potential side effects and their
						use must be justified on the basis of expected benefits to the employee. Unless
						frank and severe symptoms are present, therapeutic chelation is not
						recommended, given the opportunity to remove an employee from exposure and
						allow the body to naturally excrete accumulated lead. As a diagnostic aid, the
						chelation mobilization test has limited applicability. It offers very limited
						utility as a biomarker of long-term lead exposure, and does not predict the
						clinical efficacy of chelation.
Employers are required to ensure that accurate records
						are maintained on exposure assessment, including environmental monitoring,
						medical surveillance, and medical removal for each employee. Exposure
						assessment records must be kept for at least 30 years. Medical surveillance
						records must be kept for the duration of employment plus 30 years except in
						cases where the employment was less than one year. If duration of employment is
						less than one year, the employer need not retain this record beyond the term of
						employment if the record is provided to the employee upon termination of
						employment. Medical removal records also must be maintained for the duration of
						employment. All records required under the standard must be made available upon
						request to the Cal/OSHA Chief, and the National Institute for Occupational
						Safety and Health (NIOSH). Employers must also make environmental and
						biological monitoring and medical removal records available to affected
						employees and to former employees or their authorized employee representatives.
						Employees or their specifically designated representatives have access to their
						entire medical surveillance records.
In addition, the standard requires that the employer
						inform all employees who are exposed to lead at or above the action level on
						any one day; who are exposed to lead that may cause skin or eye irritation
						(e.g., lead arsenate, lead azide); or who perform trigger tasks of the
						provisions of the standard and all its appendices, the purpose and description
						of medical surveillance, and provisions for medical removal protection if
						temporary removal is required. An understanding of the potential health effects
						of lead exposure by all exposed employees along with full understanding of
						their rights under the lead standard is essential for an effective monitoring
						program.
II. Adverse Health Effects of Inorganic Lead
Although the toxicity of lead has been known for 2,000
						years, the knowledge of the complex relationship between lead exposure and
						human response is still being refined. Significant research into the toxic
						properties of lead continues throughout the world. Scientific evidence shows
						multiple health effects at BLLs once thought to be without recognized harm.
						Prolonged exposure to lead levels below the previous Cal/OSHA BLL threshold of
						50 µg/dl can result in adverse cumulative effects. Some of these health
						effects may be reversible and some may be permanent.
The provisions of the lead standard are founded on two
						prime medical judgments: first, the prevention of adverse health effects from
						exposure to lead throughout a working lifetime requires that employee BLLs be
						maintained as low as possible, and second, the BLLs of employees who are trying
						to conceive should be maintained below 3.5 µg/dl to minimize adverse
						reproductive health effects. The lead standard is designed to detect BLL
						increases early and take action to control exposures. The adverse effects of
						lead on reproduction are being actively researched and Cal/OSHA encourages the
						PLHCP to remain abreast of recent developments in the area to best advise
						pregnant employees or employees planning to conceive children.
The spectrum of health effects caused by lead exposure
						can be subdivided into four developmental stages: physiological changes of
						uncertain significance, pathophysiological changes, overt symptoms (morbidity),
						and mortality. Within this process there are no sharp distinctions, but rather
						a continuum of effects. Boundaries between categories overlap due to the wide
						variation of individual responses and exposures in the working population.
						OSHA's development of the lead standard focused on pathophysiological changes
						as well as later stages of disease.
In terms of mechanisms of disease, lead interferes with
						cellular metabolism in tissues throughout the body. As a divalent cation, lead
						interferes with calcium metabolism which affects, for example,
						neurotransmission and vascular tone. Lead has a high affinity for negatively
						charged sulfhydryl groups, ultimately affecting the synthesis of heme required
						for production of hemoglobin, cytochromes involved in cellular respiration, and
						microsomal oxidases involved in biotransformation pathways. In addition, lead
						increases reactive oxygen species, which effects vascular tone. Lead also
						affects cell membranes and nucleic acids with multi-system effects. In the
						nervous system, lead alters the permeability of the blood brain barrier and
						accumulates in astroglia. Other modes of action include cell death,
						genotoxicity, inflammation, and endocrine disruption.
1. Cardiovascular Effects. Current evidence indicates a
						causal relationship between lead exposure and hypertension, and between lead
						exposure and coronary heart disease. Prospective cohort studies have
						demonstrated an approximate 50% increase in cardiovascular mortality associated
						with chronic BLLs of 10 µg/dl or greater. Increased cardiovascular
						mortality has also been associated with BLLs below 10 µg/dl. Various
						mechanisms of action may mediate the hypertensive effect, including oxidative
						stress, inflammation, hormonal and blood pressure regulatory-system
						dysfunction, and vasomodulator imbalance. These mechanisms, and possibly
						subclinical atherosclerosis which has been demonstrated in some studies,
						likewise contribute to coronary heart disease. Since hypertension is a
						significant risk factor for heart disease, stroke, and renal insufficiency,
						lead exposure may exert an important influence on cardiovascular,
						cerebrovascular, and renovascular mortality. Nonetheless, lead exposure is
						associated with increased cardiovascular and stroke mortality even after
						accounting for the effects of hypertension.
2. Heme Synthesis Inhibition. The earliest hematologic
						effect involves lead's ability to inhibit at least two enzymes of the heme
						synthesis pathway at very low BLLs. Inhibition of delta-aminolevulinic acid
						dehydratase (ALA-D) which catalyzes the conversion of delta-aminolevulinic acid
						(ALA) to protoporphyrin is observed at a BLL as low as 10 µg/dl. At a BLL
						of 40 µg/dl, more than 20% of the population would have 70% inhibition of
						ALA-D. There is an exponential increase in ALA excretion at BLLs greater than
						40 µg/dl.
Another enzyme, ferrochelatase, is also inhibited at low
						BLLs. Inhibition of ferrochelatase leads to increased free erythrocyte
						protoporphyrin (FEP) in the blood which can then bind to zinc to yield zinc
						protoporphyrin (ZPP). At a BLL of 50 µg/dl or greater, nearly 100% of the
						population will have an increase in FEP. There is also an exponential
						relationship between BLLs greater than 40 µg/dl and the associated ZPP
						level, which has led to the development of the ZPP screening test for lead
						exposure.
While the significance of these effects is subject to
						debate, these enzyme disturbances are early stages of a disease process which
						eventually results in the clinical symptoms of lead poisoning. Whether or not
						the effects do progress to the later stages of clinical disease, disruption of
						these enzyme processes over a working lifetime is a material impairment of
						health.
One of the eventual results of lead-induced inhibition of
						enzymes in the heme synthesis pathway is anemia which can be asymptomatic if
						mild, but is associated with a wide array of symptoms including dizziness,
						fatigue, and tachycardia when more severe. Hematopoietic effects tend to occur
						at a BLL threshold of 10-20 µg/dL; however, bone lead stores from chronic
						exposure may continue to exert subclinical effects on hematopoiesis, regardless
						of current BLL. Once BLLs reach 50 µg/dl, a definite decrease in
						hemoglobin is evident, although most cases of lead-induced anemia, as well as
						shortened red-cell survival times, occur at BLLs exceeding 80 µg/dl.
						Inhibited hemoglobin synthesis is more common in chronic cases, whereas
						shortened erythrocyte life span is more common in acute cases.
In lead-induced anemias, there is usually a
						reticulocytosis along with the presence of basophilic stippling, and ringed
						sideroblasts, although none of the above are pathognomonic for lead-induced
						anemia.
3. Neurological Effects. Inorganic lead has been found to
						have toxic effects on both the central and peripheral nervous systems. The
						earliest stages of lead-induced central nervous system effects are manifested
						by behavioral disturbances and central nervous system symptoms including
						irritability, restlessness, insomnia and other sleep disturbances, fatigue,
						vertigo, headache, poor memory, tremor, depression, and apathy. With more
						severe exposure, symptoms can progress to drowsiness, stupor, hallucinations,
						delirium, convulsions, and coma.
The most severe and acute form of lead poisoning which
						usually follows ingestion or inhalation of large amounts of lead is acute
						encephalopathy which may arise precipitously with the onset of intractable
						seizures, coma, cardiopulmonary arrest, and death within 48 hours.
Lead exposure is associated with decrements in
						neurological function in adults. Effects at BLLs [LESS THAN EQUAL TO]10
						µg/dl include decreased cognitive function, altered behavior and mood,
						and altered neuromotor and neurosensory function. At higher BLLs, a variety of
						decrements in cognitive function and behavior and nerve function can occur.
						These effects may be irreversible.
The peripheral neuropathy resulting from lead exposure
						characteristically involves only motor function with minimal sensory damage and
						has a marked predilection for the extensor muscles of the most active
						extremity. The peripheral neuropathy can occur with varying degrees of
						severity. The earliest and mildest form which can be detected in employees with
						BLLs over 30 µg/dl is manifested by slowing of motor nerve conduction
						velocity often without clinical symptoms. With progression of the neuropathy
						there is development of painless extensor muscle weakness usually involving the
						extensor muscles of the fingers and hand in the most active upper extremity,
						followed in severe cases by wrist drop or, much less commonly, foot
						drop.
In addition to slowing of nerve conduction,
						electromyographical studies in patients with BLLs greater than 50 µg/dl
						have demonstrated a decrease in the number of acting motor unit potentials, an
						increase in the duration of motor unit potentials, and spontaneous pathological
						activity including fibrillations and fasciculations. Essential tremor in some
						studies has been shown to occur at BLLs less than 10 µg/dl.
While the peripheral neuropathies can occasionally be
						reversed with therapy, again such recovery is not ensured particularly in the
						more severe neuropathies and often improvement is only partial. The lack of
						reversibility is felt to be due in part to segmental demyelination.
4. Gastrointestinal. Lead may also affect the
						gastrointestinal system producing abdominal colic or diffuse abdominal pain,
						constipation, obstipation, diarrhea, anorexia, nausea, and vomiting. Lead colic
						may develop at 80 µg/dl, whereas milder, nonspecific gastrointestinal
						discomfort and constipation occur with levels higher than 60
						µg/dl.
5. Renal. Renal toxicity represents one of the most
						serious health effects of lead poisoning. Kidney dysfunction is thought to
						occur at chronic BLLs of 5-10 µg/dl or greater but also may arise after
						acute high-dose lead exposures. In the early stages of disease nuclear
						inclusion bodies can frequently be identified in proximal renal tubular cells.
						Renal function remains normal and the changes in this stage are probably
						reversible. With more advanced disease there is progressive interstitial
						fibrosis and impaired renal function. Eventually extensive interstitial
						fibrosis ensues with sclerotic glomeruli and dilated and atrophied proximal
						tubules; all represent end stage kidney disease. Azotemia can be progressive,
						eventually resulting in frank uremia necessitating dialysis. There is
						occasionally associated hypertension and hyperuricemia with or without
						gout.
Early kidney disease is difficult to detect. The
						urinalysis is normal in early lead nephropathy and the blood urea nitrogen and
						serum creatinine increase only when two-thirds of kidney function is lost.
						Measurement of creatinine clearance can often detect earlier disease as can
						other methods of measurement of glomerular filtration rate. An abnormal
						chelation mobilization test has been used to differentiate between lead-induced
						and other nephropathies, but this procedure is not widely accepted.
6. Reproductive Effects. Exposure to lead can have
						serious effects on reproductive function in both males and females. In male
						employees exposed to lead there can be a decrease in sexual drive, impotence,
						decreased ability to produce healthy sperm, and sterility. Malformed sperm
						(teratospermia), decreased number of sperm (hypospermia), and sperm with
						decreased motility (asthenospermia) can all occur. These adverse effects may
						occur at BLLs of 20 µg/dl or greater. Furthermore, there appears to be a
						dose-response relationship for teratospermia in lead-exposed employees.
Females exposed to lead may experience menstrual
						disturbances including dysmenorrhea, menorrhagia, and amenorrhea. Following
						exposure to lead, females have a higher frequency of sterility, premature
						births, miscarriages, and stillbirths.
Germ cells can be affected by lead and lead can cause
						genetic damage in the egg or sperm cells before conception and contribute to
						failure to implant, miscarriage, stillbirth, or birth defects.
Maternal lead exposure during pregnancy is associated
						with gestational hypertension, spontaneous abortion, low birth weight, and
						impaired neurodevelopment.
Lead can pass through the placental barrier and lead
						levels in the birthing parent's blood are comparable to concentrations of lead
						in the umbilical cord at birth. Transplacental passage becomes detectable at
						12-14 weeks of gestation and increases until birth.
There is little direct data on damage to the fetus from
						exposure to lead but it is generally assumed that the fetus and newborn would
						be at least as susceptible to neurological damage as young children. Current
						evidence indicates that there is no known lower limit of toxicity at any age.
						Lead exposure in children can cause significant neurobehavioral impairments
						including cognitive dysfunction and hyperactivity. Therefore, people planning
						to conceive should maintain BLLs less than 3.5 µg/dl.
7. Other Toxic Effects. Debate and research continue on
						the effects of lead on the human body. Lead may impair the immune and endocrine
						systems, including thyroid function and the pituitary-adrenal axis, but these
						effects and the corresponding level of exposure have not been well defined.
						Also, although the epidemiologic data is limited and inconsistent, based on
						toxicologic data and animal studies, lead is considered a probable human
						carcinogen by several authoritative sources.
III. Medical Evaluation
The most important principle in evaluating an employee
						for any occupational disease including lead poisoning is a high index of
						suspicion on the part of the examining PLHCP. As discussed in section II, lead
						can affect numerous organ systems and produce a wide array of signs and
						symptoms, most of which are non-specific and subtle in nature at least in the
						early stages of disease. Unless serious concern for lead toxicity is present,
						many of the early clues to diagnosis may easily be overlooked.
The crucial initial step in the medical evaluation is
						recognizing that an employee's employment can result in exposure to lead. The
						employee will frequently be able to define exposures to lead and lead
						containing materials but often will not volunteer this information unless
						specifically asked. In other situations the employee may not know of any
						exposures to lead but the suspicion might be raised on the part of the PLHCP
						because of the industry or occupation of the employee. Potential occupational
						exposure to lead and its compounds occur in many occupations in the
						construction industry, including demolition and salvaging operations, painting,
						removal or encapsulation of materials containing lead, construction,
						alteration, repair or renovation of structures containing lead, transportation,
						disposal, storage or containment of lead or lead-containing materials on
						construction sites, and maintenance operations associated with construction
						activities.
Once the possibility for lead exposure is raised, the
						focus can then be directed toward eliciting information from the medical
						history, physical exam, and finally from laboratory data to evaluate the
						employee for potential lead toxicity.
A complete and detailed work history is important in the
						initial evaluation. A listing of all previous employment with information on
						job description, exposure to fumes or dust, known exposures to lead or other
						toxic substances, a description of any personal protective equipment used, and
						previous medical surveillance should all be included in the employee's record.
						Where exposure to lead is suspected, information concerning on-the-job personal
						hygiene, smoking, eating and drinking habits in work areas, laundry procedures,
						and use of any protective clothing or respiratory protection equipment should
						be noted. A complete work history is essential in the medical evaluation of an
						employee with suspected lead toxicity, especially when long term effects such
						as neurotoxicity and nephrotoxicity are considered.
The medical history is also of fundamental importance and
						should include a listing of all past and current health-related conditions,
						current medications including proprietary drug intake and folk remedies,
						previous surgeries and hospitalizations, allergies, smoking history, alcohol
						consumption, and also non-occupational lead exposures such as hobbies (hunting,
						riflery). Also known childhood exposures should be elicited. Any previous
						history of cardiovascular, hematological, neurological, gastrointestinal,
						renal, psychological, gynecological, genetic, or reproductive problems should
						be specifically noted.
A careful and complete review of systems must be
						performed to assess both recognized complaints and subtle or slowly acquired
						symptoms which the employee might not appreciate as being significant. The
						review of symptoms should include the following:
1. General -- weight loss, fatigue, decreased
						appetite.
2. Head, Eyes, Ears, Nose, Throat (HEENT) -- headaches,
						visual disturbances or decreased visual acuity, hearing deficits or tinnitus,
						pigmentation of the oral mucosa, or metallic taste in mouth.
3. Cardiopulmonary -- shortness of breath, cough, chest
						pains, palpitations, or orthopnea.
4. Gastrointestinal -- nausea, vomiting, heartburn,
						abdominal pain, constipation, or diarrhea.
5. Neurologic -- irritability, insomnia, weakness
						(fatigue), dizziness, loss of memory, confusion, hallucinations,
						incoordination, ataxia, decreased strength in hands or feet, disturbances in
						gait, difficulty in climbing stairs, or seizures.
6. Hematologic -- pallor, easy fatigability, abnormal
						blood loss, or melena.
7. Reproductive (male and female, and spouse where
						relevant) -- history of infertility, impotence, loss of libido, abnormal
						menstrual periods, history of miscarriages, stillbirths, or children with birth
						defects.
8. Musculoskeletal -- muscle and joint pains.
The physical examination should emphasize the
						neurological, gastrointestinal, and cardiovascular systems. The employee's
						weight and blood pressure should be recorded. Historically, the oral mucosa was
						checked for pigmentation characteristic of a possible Burtonian or lead line on
						the gingiva. However, the lead line may not be present even in severe lead
						poisoning if good oral hygiene is practiced.
The presence of pallor on skin examination may indicate
						an anemia which, if severe, might also be associated with a tachycardia. If an
						anemia is suspected, an active search for blood loss should be undertaken
						including potential blood loss through the gastrointestinal tract.
A complete neurological examination should include an
						adequate mental status evaluation including a search for behavioral and
						psychological disturbances, memory testing, evaluation for irritability,
						insomnia, hallucinations, and mental clouding. Gait and coordination should be
						examined along with close observation for tremor. A detailed evaluation of
						peripheral nerve function including careful sensory and motor function testing
						is warranted. Strength testing particularly of extensor muscle groups of all
						extremities is of fundamental importance.
Cranial nerve evaluation should also be included in the
						routine examination.
The abdominal examination should include auscultation for
						bowel sounds and abdominal bruits and palpation for organomegaly, masses, and
						diffuse abdominal tenderness.
Cardiovascular examination should evaluate possible early
						signs of ischemic heart disease and congestive heart failure. Pulmonary status
						should be addressed particularly if respiratory protection is
						contemplated.
As part of the medical evaluation, the lead standard
						requires the following laboratory studies:
1. Blood lead level;
2. Hemoglobin and hematocrit determinations, red cell
						indices, and examination of the peripheral blood smear to evaluate red blood
						cell morphology;
3. Blood urea nitrogen;
4. Serum creatinine;
5. Routine urinalysis with microscopic
						examination;
6. A zinc protoporphyrin (ZPP) level for each employee
						whose last BLL was at or above 20 µg/dl.
In addition to the above, the PLHCP is authorized to
						order any further laboratory or other tests which they deem necessary in
						accordance with sound medical practice. The evaluation must also include
						pregnancy testing or laboratory evaluation of male fertility if requested by
						the employee. Additional tests which are probably not warranted on a routine
						basis but may be appropriate when blood lead and ZPP levels are equivocal
						include delta-aminolevulinic acid and coproporphyrin concentrations in the
						urine, and dark-field illumination for detection of basophilic stippling in red
						blood cells.
If an anemia is detected further studies including a
						careful examination of the peripheral smear, reticulocyte count, stool for
						occult blood, serum iron, total iron binding capacity, bilirubin, and, if
						appropriate, vitamin B12 and folate may be of value in attempting to identify
						the cause of the anemia.
If a peripheral neuropathy is suspected, nerve conduction
						studies are warranted both for diagnosis and as a basis to monitor any
						therapy.
If renal disease is questioned, a 24-hour urine
						collection for creatinine clearance, protein, and electrolytes may be
						indicated. Elevated uric acid levels may result from lead-induced renal disease
						and a serum uric acid level might be performed.
An electrocardiogram and chest x-ray may be obtained as
						deemed appropriate.
Sophisticated and highly specialized testing should not
						be done routinely and where indicated should be under the direction of a
						specialist.
IV. Laboratory Evaluation
The BLL at present remains the single most important test
						to monitor lead exposure and is the test used in the medical surveillance
						program under the lead standard to guide employee medical removal. The ZPP
						currently remains an ancillary test due to its lack of sensitivity.
This section will discuss the BLL and ZPP in detail and
						will outline their relative advantages and disadvantages. Other blood tests
						currently available to evaluate lead exposure will also be reviewed.
BLL, a measure of the amount of lead currently found in
						the blood, reflects both recent exogenous exposure as well as endogenous
						redistribution of lead stored in bone. BLL does not reflect the total body
						burden. One reason for this is that lead has a high affinity for bone and up to
						90% of the body's total lead is deposited there. A very important component of
						the total lead body burden is lead in soft tissue (liver, kidney, and brain).
						This fraction of the lead body burden, the biologically active lead, is not
						entirely reflected by BLLs since it is a function of the dynamics of lead
						absorption, distribution, deposition in bone and excretion. Following
						discontinuation of exposure to lead, the excess body burden is only slowly
						mobilized from bone and other relatively stable body stores and
						excreted.
When interpreting a person's BLL, three key questions to
						keep in mind are whether the exposure history has been acute or chronic; recent
						or remote; high or low. For instance, a high BLL may only represent recent
						heavy exposure to lead without a significant total body excess and likewise a
						low BLL does not exclude an elevated total body burden of lead.
Also due to its correlation with recent exposures, the
						BLL may vary considerably over short time intervals.
To minimize laboratory error and erroneous results due to
						contamination, blood specimens must be carefully collected after thorough
						cleaning of the skin with appropriate methods using lead-free blood containers
						and analyzed by a reliable laboratory. Under the standard, samples must be
						analyzed in laboratories that are CLIA-approved (under the federal Clinical
						Laboratory Improvement Amendments (CLIA) regulations).
The determination of lead in urine is generally
						considered a less reliable monitoring technique than analysis of whole blood
						primarily due to individual variability in urinary excretion capacity as well
						as the technical difficulty of obtaining accurate 24-hour urine collections. In
						addition, employees with renal insufficiency, whether due to lead or some other
						cause, may have decreased lead clearance and consequently urine lead levels may
						underestimate the true lead burden. Therefore, urine lead levels should not be
						used as a routine test.
The ZPP test, unlike the blood lead determination, is an
						indirect and relatively insensitive biomarker of lead absorption. Zinc
						protoporphyrin results from the inhibition of the enzyme ferrochelatase which
						catalyzes the insertion of an iron molecule into the protoporphyrin molecule,
						which then becomes heme. If iron is not inserted into the molecule, then zinc,
						having a greater affinity for protoporphyrin, takes the place of the iron,
						forming ZPP. The level of circulating ZPP may not rise until a BLL of 20
						µg/dl in some adults and is not greater than 90% sensitive until the BLL
						exceeds 50 µg/dl. Increases in BLLs beyond 40 µg/dl are associated
						with exponential increases in ZPP. The upper limit of normal for ZPP varies
						some between labs but is usually between 35 and 40 µg/dl.
Whereas BLLs fluctuate over short time spans, ZPP levels
						remain relatively stable. ZPP is measured directly in red blood cells and is
						present for the cell's entire 120 day life-span. Therefore, the ZPP level in
						blood reflects the average ZPP production over the previous 3-4 months and
						consequently the average lead exposure during that time interval. The ZPP
						requires more time than the blood lead to reach significantly elevated levels;
						the return to normal after discontinuing lead exposure is also slower, lagging
						the BLL by about 2-6 weeks. Therefore, the ZPP may be useful to assess
						chronicity of exposure. For example, an elevated BLL and normal ZPP suggest
						recent exposure, while an elevated BLL and elevated ZPP suggest chronic/ongoing
						exposure.
It is recommended that a hematocrit be determined
						whenever a confirmed ZPP of 50 µg/dl is obtained to rule out a
						significant underlying iron deficiency anemia. If the ZPP is in excess of 100
						µg/dl and not associated with abnormal elevations in BLLs, the laboratory
						should be checked to be sure that blood leads were determined using a
						laboratory that is CLIA-approved. Repeat periodic blood lead studies should be
						obtained in all individuals with elevated ZPP levels to be certain that an
						associated elevated BLL has not been missed due to transient fluctuations in
						blood leads.
ZPP has a characteristic fluorescence spectrum with a
						peak at 594 nanometers which is detectable with a hematofluorometer. The
						hematofluorometer is accurate and portable and can provide on-site,
						instantaneous results for employees who can be frequently tested via a finger
						prick.
However, careful attention must be given to calibration
						and quality control procedures. Limited data on blood lead-ZPP correlations and
						the ZPP levels which are associated with the adverse health effects discussed
						in section II are the major limitations of the test. Also it is difficult to
						correlate ZPP levels with environmental exposure and there is some variation of
						response with age and sex.
Levels of delta-aminolevulinic acid (ALA) in the urine
						are also used as a measure of lead exposure. Increasing concentrations of ALA
						are believed to result from the inhibition of the enzyme delta-aminolevulinic
						acid dehydratase (ALA-D). Although the test is relatively easy to perform,
						inexpensive, and rapid, the disadvantages include variability in results, the
						necessity to collect a complete 24 hour urine sample which has a specific
						gravity greater than 1.010, and also the fact that ALA decomposes in the
						presence of light.
The pattern of porphyrin excretion in the urine can also
						be helpful in identifying lead intoxication. With lead poisoning, the urine
						concentrations of coproporphyrins I and II, porphobilinogen and uroporphyrin I
						rise. The most important increase, however, is that of coproporphyrin III, but
						its correlations with BLLs and ZPP are not as good as those of ALA. Increases
						in urinary porphyrins are not diagnostic of lead toxicity and may be seen in
						porphyria, some liver diseases, and in patients with high reticulocyte
						counts.
V. Summary. The standard for inorganic lead in the
						construction industry places significant emphasis on the medical surveillance
						of all employees exposed to levels of inorganic lead at or above the action
						level of 2 µg/m3 TWA, and as interim
						protection for employees performing trigger tasks. The PLHCP has a fundamental
						role in this surveillance program, and in the operation of the medical removal
						protection program.
Even with adequate employee education on the adverse
						health effects of lead and appropriate training in work practices, personal
						hygiene and other control measures, the PLHCP has a primary responsibility for
						evaluating potential lead toxicity in the employee. It is only through a
						careful and detailed medical and work history, a complete physical examination,
						and appropriate laboratory testing that an accurate assessment can be made.
						Many of the adverse health effects of lead toxicity are either irreversible or
						only partially reversible and therefore early detection of disease is very
						important.
This document outlines the medical monitoring program as
						defined by the occupational safety and health standard for inorganic lead. It
						reviews the adverse health effects of lead poisoning and describes the
						important elements of the history and physical examinations as they relate to
						these adverse effects. Finally, the appropriate laboratory testing for
						evaluating lead exposure and toxicity is presented.
It is hoped that this review and discussion will give
						PLHCPs a better understanding of the Cal/OSHA lead standard, with the ultimate
						goal of protecting the health and well-being of employees exposed to lead who
						are under their care.