Surface Contamination Levels

John Hill, CIH, CSPHealth and Safety Program Manager

EFCOG Worker Safety and Health Subgroup Meeting

April 16, 2019 SRNS‐J1300‐2019‐00007

Surface Contamination

Why should we care about surface contamination levels?

Help prevent:• Possible dermal absorption• Possible ingestion• Possible eye contact• Transfer of the material to other areas• Transfer of the material home and potentially exposing family

members

Also:• Verify housekeeping efforts in the area• Verify controls are effective

2

If we take a swipe sample for a surface contaminant,

What regulatory criteria are we using to compare to the results and determine the surface is clean enough?

3

Surface Contamination

Asbestos 29 CFR 1910.1001– 1910.1001(k)(1): All surfaces shall be maintained as free practicable of ACM waste

and debris and accompanying dust.

Inorganic Arsenic 29 CFR 1910.1018– 1910.1018(k)(1): All surfaces shall be maintained as free practicable of accumulations

of inorganic arsenic.

Lead 29 CFR 1910.1025– 1910.1025(h)(1): All surfaces shall be maintained as free practicable of accumulations

of lead.

Chromium (VI) 29 CFR 1910.1026– 1910.1026(j)(1)(i): All surfaces shall be maintained as free practicable of

accumulations of chromium (VI).

4

OSHA Surface Contamination Levels

Cadmium 29 CFR 1910.1027– 1910.1027(k)(1): All surfaces shall be maintained as free practicable of accumulations

of cadmium.

1,2‐dibromo‐3‐chloropropane 29 CFR 1910.1044– 1910.1044(k)(1)(i): All workplace surfaces shall be maintained free of visible

accumulations of DBCP.

Acrylonitrile 29 CFR 1910.1045– 1910.1045(k)(1): All surfaces shall be maintained free of visible accumulations of liquid

AN.

Methylenedianiline 29 CFR 1910.1050– 1910.1050(l)(1): All surfaces shall be maintained as free practicable of accumulations

of MDA.

5

OSHA Surface Contamination Levels

EPAPolychlorinated Biphyenyls (PCBs) 40 CFR 761.125(c)(3) and (4)

Clean up levels vary by access area (restricted or unrestricted) and surface type:

Varies from 10 ug/100 cm2 to 100 ug/100 cm2 for surfaces

Varies from 10 ppm to 25 ppm for soils

DOEBeryllium 10 CFR 850Housekeeping level is 3.0 ug/100 cm2 Free Release Criteria – 0.2 ug/100 cm2

6

Other Surface Contamination Levels

When asked about the criteria, OSHA said:

OSHA Letter of Interpretation June 21, 1985

“Although some OSHA standards contain housekeeping provisions which address the issue of surface contamination, there are currently no surface contamination criteria…”

7

Surface Contamination Criterion Levels

OSHA Technical Manual ‐ Section II, Chapter 2Surface Contaminants, Skin Exposure, Biological Monitoring and Other Analyses III A Surface Wipe Sampling

“In industries such as the pharmaceutical industry, a common rule of thumb is to use the maximum allowable dose (based on the chemical's airborne exposure limit in units of μg/m3) and the approximate area of a worker's hand (100 cm2) to arrive at an acceptable value for surface contamination in work areas (i.e., a housekeeping standard). For example, if the eight‐hour TWA exposure limit for a chemical is 1 μg/m3, the maximum allowable dose for that chemical is 10 μg. As noted in Section II.C., the chemical's eight‐ hour time‐weighted average (TWA) airborne exposure limit is multiplied by 10 m3, the volume of air inhaled by an average worker in an eight‐hour workday, to determine the maximum acceptable dose (i.e., 1 μg/m3 x 10 m3 = 10 μg). The maximum acceptable dose is then divided by the area of a worker's hand to determine the acceptable surface limit of 10 μg/100 cm2 or 0.1 μg/cm2. By this rule of thumb, the amount of contaminant picked up by one hand contacting the contaminated surface is equivalent to the toxic dose allowed by the eight‐hour TWA airborne exposure limit (determined by multiplying by the 10 m3 of air breathed by an average worker in an eight‐hour workday).”

8

Surface Contamination Criterion Levels

OSHA Technical Manual ‐ Section II, Chapter 2Surface Contaminants, Skin Exposure, Biological Monitoring and Other Analyses

III A Surface Wipe Sampling

9

“For highly toxic materials, hazardous levels of surface contamination will often be invisible to the unaided eye, while limits of detection for wipe sampling will be considerably more sensitive. For example, the limit of visible residue for active pharmaceutical ingredients is typically 1–5 μg/cm2, whereas good surface wipe sampling techniques can have limits of detection in the low nanogram range. This underscores the essential value of surface wipe sampling in areas where highly toxic materials such as lead or chromium (VI) are present.”

Surface Contamination Criterion Levels

Contaminant OSHA Requirement DOE Requirement

Asbestos As free as practicable

Inorganic Arsenic As free as practicable

Lead As free as practicable

Chromium (VI) As free as practicable

Cadmium As free as practicable

DBCP Free of visible accumulation

Acrylonitrile Free of visible accumulation

Methylenedianiline As free as practicable

Beryllium 3.0 ug/100 cm2 (Housekeeping)0.2 ug/100 cm2 (free release)

10

Surface Contamination Regulatory Levels

Contaminant EPA Requirement HUD

Asbestos

Inorganic Arsenic

Lead 40 ug/ft2 for floors250 ug/ft2 for interior window sills

40 ug/ft2 for floors250 ug/ft2 for interior window sills

Chromium (VI)

Cadmium

DBCP

Acrylonitrile

Methylenedianiline

11

Surface Contamination Other Agency Levels

Surface Contamination Levels OSHA Calculation

12

Using the process in the OSHA Technical Manual:

Surface Level Criteria = TWA (µg/m3) X 10 m3

For example:

Lead TLV = 0.05 mg/m3 = 50 µg/m3

50 µg/m3 x 10 m3 = 500 µg maximum acceptable dose for lead

For the acceptable surface limitMaximum Acceptable Dose / Approximate Surface Area of Workers Hand (100 cm2)

For lead500 µg / 100 cm2 = 5 ug/cm2

Contaminant OSHA DOE EPA OSHA Tech Manual Method

HUD

Inorganic Arsenic As free as practicable

100.0 µg/100 cm2

Lead As free as practicable

40 ug/ft2 for floors 250 ug/ft2 for interior window sills

500.0 µg/100 cm2 40 ug/ft2 for floors 250 ug/ft2 for interior window sills

Chromium (VI) As free as practicable

50.0 µg/100 cm2

Cadmium As free as practicable

50.0 µg/100 cm2

DBCP Free of visible accumulation

0.1 µg/100 cm2

Acrylonitrile Free of visible accumulation

43 µg/100 cm2

Methylenedianiline As free as practicable

0.8 µg/100 cm2

Beryllium 3.0 µg/100 cm2

13

Surface Contamination Levels (Housekeeping)

OSHA Letter of Interpretation on “Practicable”

14

• January 13, 2003

Dear Mr. White:

…

The paragraphs you referenced in your letter are from the Lead‐in‐Construction Standard, 29 CFR 1926.62, and concern housekeeping and hygiene. Your questions had to do with the level of measurable lead contamination which meets the definition of practicable for areas such as rafters.….

The term "practicable" was used in the standard, as each workplace will have to address different challenges to ensure that lead‐surface contamination is kept to a minimum. It is OSHA's view that a housekeeping program which is as rigorous as "practicable" is necessary in many jobs to keep airborne lead levels below permissible exposure conditions at a particular site.…The proposed language for this provision required that "surfaces...be maintained free of accumulation of lead which, if dispersed, would result in airborne concentrations above the permissible exposure limit." This requirement would be very difficult for the employer to comply with, and OSHA to enforce, because it would be nearly impossible to objectively determine when the condition in the standard would occur. OSHA's view, therefore, is that a rigorous housekeeping program is absolutely necessary to keep airborne lead levels below permissible limits but that the obligation should be measured by "practicability." As you are aware, the requirement to maintain surfaces "as free as practicable" is performance‐oriented. No quantitative levels of lead in dust are identified by the standard. The requirement is met when the employer is vigilant in his efforts to ensure that surfaces are kept free of accumulations of lead‐containing dust. The role of the Compliance Safety and Health Officer (CSHO) is to evaluate the employer's housekeeping schedule, the possibility of exposure from these surfaces, and the characteristics of the workplace.

In situations where employees are in direct contact with lead‐contaminated surfaces, such as working surfaces or floors in change rooms, storage facilities and, of course, lunchroom and eating facilities, OSHA has stated that the Agency would not expect surfaces to be any cleaner than the 200‐ug/ft2 HUD level. …

Summary

15

• There is no occupational standard other than the ambiguous “as clean as practicable”.

• The EPA and HUD levels are not set up for an occupational environment.

• The approach in the OSHA Technical Manual from the pharmaceutical industry seems reasonable. That approach is similar to what the AIHA recommends from dermal exposures.

• Remember to take into account analytical limitations when setting any surface contamination level.