Locating, Understanding and Implementing Medical Surveillance Standards

Standards have their limits

Type/quality of data May be outdated Special considerations: individual differences,

nonstandard work schedule, mixtures, moonlighting, etc.

Effect depends on real-world conditions:◦ Health status◦ Work rate◦ Working conditions

May be based on politics, economics, etc.-- not just health!

Benefits of Biological Monitoring Biological monitoring accounts for actual

absorption Can reveal absorption by routes other than

inhalation Can assess effectiveness of PPE Can show effects of moonlighting/hobbies Reveals idiosyncratic susceptibility

Limits of Biological Monitoring Very few compounds have adequate

pharmacokinetic data Invasive or inconvenient Not appropriate for chemicals with

immediate effect, such as irritants Could lead to discrimination Samples could be analyzed for other agents

Agencies and Standards ACGIH:

◦ TLV, STEL, Ceiling limit◦ BEI

NIOSH: REL, Criteria Documents OSHA:

◦ PEL (permanent, interim, ETS)◦ Action Level

Washington State L & I ANSI

How to find a standard? OSHA

◦ http://osha.gov/◦ Go to “Safety and Health Topics”◦ “Medical Screening and Surveillance”-- “Medical

Surveillance” ◦ Pick a topic!◦ OSHA standards fall under 29 CFR Part 1910.

How to find a standard? WISHA

◦ Go to WA Dept. of Labor and Industries: http://www.lni.wa.gov/

◦ “Safety”◦ “A-Z Safety and Health Topics”◦ “Medical Surveillance”◦ Choose one! ◦ WISHA Standards fall under Title 296 WAC.

How to find a standard? NIOSH

◦ http://www.cdc.gov/niosh/◦ “Surveillance”◦ “Medical Test Database”◦ Or, click on the specific exposure of interest.

e.g., Lead-- ABLES Methyl Parathion

How are we doing? Straif, K. & Silverstein, M. (1997).

“Comparison of U.S. Occupational Safety and Health Standards and German Berufsgenossenschaften guidelines for preventive occupational health examinations.” American Journal of Industrial Medicine 31: 373-380.

How can employers implement appropriate screening?

OSHA/WISHA standards for requirements NIOSH and others for recommendations

◦ Remember standards have limitations! Consider:

◦ Quality control◦ Standardization◦ Centralization/cost-effectiveness◦ Targeted surveillance◦ Ethical issues

References Morgan, M.S. & Hostman, S.W. (2008). Section 5: occupational

exposure guidelines and standards. In Introduction to Occupational Hygiene.

Morgan, M .S. & Hostman, S.W. (2008). Section 10: biological monitoring. In Introduction to Occupational Hygiene.

Straif, K. & Silverstein, M. (1997). “Comparison of U.S. Occupational Safety and Health Standards and German Berufsgenossenschaften guidelines for preventive occupational health examinations.” American Journal of Industrial Medicine 31: 373-380.

40 yo undocumented immigrant cotton worker presents with mildly excessive lacrimation, salivation, acute diarrhea. About 5 hours ago he was in the field when an unidentified liquid was spilled on his hands while loading it into a spreader. He was wearing no PPE at the time. No prior medical history available. Patient speaks very broken English. He initially presented, reluctantly, to his supervisor due concerns about mild dyspnea and blurred vision.

a) Order a serum organophosphate assay to ascertain dangerous levels in blood.

b) Order erythrocyte count and ESRc) Check for depressed levels of erythrocyte

cholinesterase activity

d) No testing indicated, this is primarily a clinical diagnosis.

a) Order a serum organophosphate assay to ascertain dangerous levels in blood.

b) Order erythrocyte count and ESRc) Check for depressed levels of

erythrocyte cholinesterase activityd) No testing indicated, this is primarily a

clinical diagnosis.

a) Administer a baseline erythrocyte cholinesterase assay to the entire field worker force.

b) Recommend thorough physical exam of all field workers in contact with the substance, especially loaders and mixers.

c) Routinely screen with blood test all workers on a biweekly basis.

d) Permanently remove any worker from workplace due to recent symptomatic acute exposure

a) Administer a baseline erythrocyte cholinesterase assay to the entire field worker force.

b) Recommend thorough physical exam of all field workers in contact with the substance, especially loaders and mixers.

c) Routinely screen with blood test all workers on a biweekly basis.

d) Permanently remove any worker from workplace due to recent symptomatic acute exposure

Medical screening and surveillance

Extrapolated from tetraethyl dithionopyrophosphate TEDP (Sulfotep), another organophospate

Preplacement medical evaluation pre-exposure red blood cell

cholinesterase and plasma cholinesterase Where no standard exists and the hazard is

minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician.

2008 Threshold Limit Values & Biolgical Exposure Indices. American Conference of Governmental Industrial Hygenists

Based on direct correlation between environmental levels (Threshold Limit Values) and protection against non-systemic effects

BEI: level below which most workers should not experience adverse health effects.

Total p-nitrophenol in urine at end of shift, end of workweek: 0.5mg/g creatinine (Ns)

Cholinesterase activity in red cells, discretionary: 70% of individuals baseline (B, NS, Sq)B – Background: present, in part, due to non-occupational exposure

Ns – Nonspecific: Determinant present after exposure to other chemicalsSq – Semi-quantitative: interpretation ambiguous

Criteria for a Recommended Standard: Occupational Exposure to Methyl Parathion. NIOSH Criteria Documents. September 1976. DHHS (NIOSH) Publication No. 77-106. http://www.cdc.gov/niosh/77-106.html Updated 1997. Viewed 25 OCT 2008

OSHA Health Guidelines: TEDP (Sulfotep) http://www.osha.gov/SLTC/healthguidelines/tedp/recognition.html viewed 25 OCT 2008

2008 Threshold Limit Values & Biological Exposure Indices. American Conference of Governmental Industrial

Hygienists, Cincinnati, OH www.acgih.org/TLV/Studies.htm

Characteristics of US Workers Whose Blood Lead Levels Trigger the Medical Removal Protection Provision, and Conformity With Biological Monitoring Requirements, 2003–2005

SangWoo Tak, ScD,1 Robert J. Roscoe, MS,1 Walter Alarcon, MD,1 Jun Ju, MS,2 John P. Sestito, JD,1 Aaron L. Sussell, PhD,1 and Geoffrey M. Calvert, MD

Background: Workers with blood lead levels (BLL) 60 mg/dl (50 mg/dl for construction workers) or with three or more consecutive BLLs over at least 6 months that average 50 mg/dl or greater are required to be removed from work involving lead exposure that exceeds the OSHA action level. This study estimates the proportion of workers with BLLs that trigger the medical removal provision by industry sector, and examines whether workers received appropriate follow-up blood lead testing.

OSHA's lead standard (29CFR 1910.1025)

Permissible Exposure Limit 50 micrograms per cubic meter of air (µg/m3) Averaged over an 8-hour workday Representative number of employees believed to

have the highest exposure levels

Action Limit 30 µg/m3 over an 8-hour workday Medical surveillance if action level

exceeded>30 days/yr

Medical Surveillance Blood lead standard of 40 µg per 100 mL

of blood Measure every six months

BLL≥ 60 µg/dl General Industry (CFR 1910.1025)

BLL≥ 50 µg/dl Construction

Average BLL of all tests over a 6-month period (or if there are less than 3 tests over a 6-month period, the average of three consecutive tests) is ≥50 µg/dl

The employer shall provide the required medical surveillance including multiple physician review without cost to employees and at a reasonable time and place.

Follow-up blood sampling tests. OSHA requires retesting within 2 weeks and monthly follow-up during the medical removal period.

neither the lead standard, nor any other OSHA standard, makes participation in the medical surveillance program mandatory for the employee.

The employer's obligation is to provide medical tests and examinations as required, whether or not an employee cooperates.

Substitution of other tests not acceptable i.e. urinary lead, hair lead

Recommendation: medical consultation prior to conducting any medical procedures

document any employee refusal to undergo it

Adults who received follow-up retesting and met eligibility to return to lead work among adults with BLLs triggering medical removal protection (n=208):Based on 17 states reporting all BLLs

References:

Medical Surveillance for Lead http://laborcommission.utah.gov/UOSH/

Outreach/ConstructionCD/www.osha.gov/pls/oshaweb/standards-10644.htm