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Safety and Health Topics > Lead Test Kits
 

Lead Test Kits
Disclaimer: On-site surface sampling test kits are commercially available. OSHA neither endorses these kits nor recommends their use. The effectiveness and applicability of these kits are the responsibility of the user. The tested products were evaluated in 1994. They may no longer be available as described or marketed by vendors cited in the report. Persons desiring to use these kits should perform a literature search to find current vendors.

Classification Product Evaluation(PE-14)
Chemist Robert G. Adler
Date September, 1994

Branch of Inorganic Methods Development OSHA Technical Center Salt Lake City, Utah

Mention of a specific product name or manufacturer is for information only. Results may not be used in advertising.

Introduction:

Contained within this report is the summary performance evaluation of commercially available kits for field testing lead in paint and other solid materials. These kits are intended mainly for consumer use to determine if hazardous amounts of lead are present, and use a colorimetric reaction with lead which can be observed immediately. When written in 1994 Federal OSHA Compliance Health and Safety Officers (CSHOs) do not have field procedures conveniently available for on-site identification of lead. Other field procedures such as portable x-ray fluorescence (XRF), electroanalysis, and flame injection are also available for on-site use; however, these techniques require expensive instrumentation and some technical sophistication. Our evaluation focused on an inexpensive simple test that could provide rapid, accurate results to OSHA CSHOs. Use of immediate response test kits, provided they are precise, accurate, and sensitive, should assist CSHOs in identifying potential lead exposures, poor housekeeping situations, and when and where to conduct further monitoring.

The two kits examined were the HybriVet Lead Check(TM) Test Kit and the Pace Environs Lead Alert(TM) Test Kit. To use either kit, a swab is rubbed over the material of interest, and a pink color formed from reagents placed on the swab is noted when lead is present in quantities greater than the detection limit. Neither kit gives a quantitative value, but attempts to give a yes/no type of response to the question "Is lead present?"

The evaluation of lead test kits is part of a continuous program at the OSHA Salt Lake Technical Center (SLTC) to determine the abilities and shortcomings of direct-reading equipment used to analyze air and other materials for toxic substances. The primary purpose of the evaluations is for the dissemination of equipment performance information to OSHA field personnel. Direct-reading instruments are mainly used by OSHA to rapidly assess concentrations of a wide variety of toxic materials in air but also in liquids and solids, and to determine if more extensive sampling should be conducted.

Determination of lead by rapid methods has become a major concern in recent years since it is apparent that lead poisoning is still occurring in workers removing or otherwise disturbing old lead-containing paint in the course of their work. Serious cases of lead poisoning continue to occur in children exposed to old flaking lead-containing paint or lead-contaminated soil. Abatement projects have become a major activity in recent years to remove lead-containing paint and other materials to reduce lead exposure to workers and the general public (10.1.-10.6.).

The term "lead-based" paint (LBP) has been defined in the Lead Exposure Reduction Act (October 29, 1992) as "paint or other surface coatings that contain lead in excess of 1.0 milligram per centimeter squared or 0.5 percent by weight" (10.7., 10.8.). In the Department of Housing and Urban Development (HUD) Interim Guidelines (September 1990, revised May 1991) (10.9.), the action level for LBP is a lead content of 1.0 mg/cm2 as measured by an XRF analyzer. When using chemical testing, the action level is either 0.5% by weight or 1.0 mg/cm2. "Lead-free" paint, on the other hand, is usually considered to be any dried coating containing no more than 0.06% (600 ppm) lead, essentially indicating no lead is added at any point in the manufacturing process. OSHA currently does not stipulate a specific amount of surface lead not to be exceeded. The OSHA CSHO examines the industrial operation or situation for potential occupational exposure to lead as a surface contaminant, and evaluates protective measures to minimize exposures. Although OSHA does not have a numeric trigger for lead as a surface contaminant, concentrations in air are strictly regulated in occupational settings (10.10., 10.11.). For the purposes of this evaluation, the HUD Guideline value of 0.5% by weight will be used as the trigger for evaluating lead test kit performance.

The HUD Interim Guidelines on Worker Protection (Chapter 8) includes discussions on worker training, enclosures, personal protective equipment, work practices, and personal hygiene. The guidelines are intended to provide, at a minimum, the level of protection of OSHA's General Industry Lead Standard (29 CFR 1910.1025) (10.10.). Both OSHA's General Industry (29 CFR 1910.1025) and lead in construction (29 CFR 1926.62) (10.11.) regulations stipulate identification of potential exposure to lead and good housekeeping practices to minimize surface contamination.

Lead detection kits are useful as a quick check for screening areas for lead abatement. A positive response is evidence of the presence of lead or a positive interference. A negative response, however, is not conclusive evidence of the absence of lead. The test provides presumptive evidence for the presence of lead, not its absence. A more thorough determination may need to be performed by a quantitative laboratory analysis of any representative bulk material available to substantiate the absence of lead. Samples are analyzed for lead at the SLTC using OSHA methods ID-121 [Atomic Absorption Spectroscopy (AAS)], ID-125G [Inductively Coupled Plasma (ICP)], or ID-206 (Solders by ICP). If necessary, lower limits of detection for lead may be achieved using ICP-Mass-Spectrometer procedures.

The Lead Alert(TM) Test Kit now sold by Sensidyne was originally developed by Frandon Enterprises, Inc. which is currently owned by Pace Environs, Inc. An extensive study reported by Pace Environs indicated that the methodology to evaluate paint samples met HUD performance standards for qualitative lead tests (10.12.).

The Lead Check(TM) Test Kit now also sold by Sensidyne has been tested by the Food and Drug Administration (FDA) and the National Institute of Standards and Technology (NIST). The FDA reported that the swabs were able to detect the presence or absence of lead in 96.6% of the pieces tested. The NIST found that the swabs were able to detect lead in paint as well as or better than other methods. The product literature indicates that 1-2 ug of leachable lead can be detected (10.7.).

Advantages and disadvantages of the lead detector test kits
  • The lead detector kits are designed to offer a simple and immediate estimation as to whether or not the lead in paint or other solid materials is at a hazardous level and whether abatement measures are needed.
  • According to the manufacturers, in addition to paint, other materials such as dust, soil, ceramics, lead crystal, solder, foil, pewter, and other metals can be examined for lead.
  • The kits are easy to use.
  • No analytical laboratory time is required.
  • The kits are inexpensive.
  • The pink color obtained upon reaction of lead with the kit reagents is very distinct.
  • The tests appear to be specific for lead when a pink color is obtained. They do not give a positive reaction with several metals used in lead-free solders.
  • The chemicals used are stated to be nontoxic; however, the usual precautions in handling any chemicals should be followed.
Note: Each kit is provided with test papers that contain lead to assure effectiveness in testing. Care should be used in handling these test media.
  • The kits are not recommended for users who are color-blind in the red/pink region of the color spectrum.
  • The kits are not designed to detect lead in water.
  • Possible interferences include barium, calcium sulfate in plaster, chromate in lead and zinc chromate, and red paint pigments. See Section 2. below.
  • The kits give only a positive/negative response. For a more thorough lead determination, the samples must be sent to a certified laboratory, or another more expensive field procedure used.

1. Lead Test Kits

On-site surface sampling test kits are commercially available. OSHA neither endorses these kits nor recommends their use. The effectiveness and applicability of these kits are the responsibility of the user.  

The Lead Test Kits evaluated, their contents, and accessories are listed in Table 1. All kits and accessories were purchased on the open market. The color responses are similar for both kits.
Table 1
Lead Detector Kits Studied
 

These were evaluated in 1994 and may not be currently available.
LEAD CHECK(TM) Test Kit
HybriVet Systems, Inc.

CONTENTS
Indicating Swabs (8 One-Time Swabs)
(Each swab containing all chemicals needed for testing.)
Positive Control Strips (6 tests/strip)
(For confirming effectiveness of testing system.)
Instructions
These were evaluated in 1994 and may not be currently available.
LEAD ALERT(TM) Wipe/Sanding Test Kit
Pace Environs

CONTENTS
Indicating Solution (Red, 1 bottle)
Leaching Solution (White, 1 bottle)
Abrasive Strips (10 One-Time Strips)
Indicating Tablet (1, in foil Pkg.)
Sample Collectors (10 One-Time Swabs)
(Double-ended, Cotton-tipped, Lead-free.)
Positive Control Strip (6 tests/strip)
(For confirming effectiveness of testing system.)
Instructions
Material Safety Data Sheets
These were evaluated in 1994 and may not be currently available.
LEAD ALERT(TM) All in One(TM) Professional Kit


CONTENTS
Same as Wipe/Sanding Kit, plus the following:
Abrasive Strips (10 additional strips)
Sample Collectors (10 additional swabs)
Plastic Vials (20)
(For holding paint chips and coring samples.)
Plastic Rods (20)
(For grinding the paint samples in the vials.)
Collection Papers (20 one-time papers)
(Backed with adhesive to help gather samples.)
These were evaluated in 1994 and may not be currently available.
Coring Tool and Brush
Pace Environs, Cary, NC

For use with the LEAD ALERT Professional Kit.

2. Interferences
 

According to the manufacturers, several interferences are possible. These interferences appear to be common to both brands of lead detector kits studied. They are discussed in Table 2.

Table 2
Lead Detection Interferences
Barium Some paints contain barium sulfate (an extender) which will produce an orange color. If a pink color is observed over the orange, a positive result is indicated. However, the pink color may also be obscured, in which case the sample should be sent to a certified laboratory, or another field method used.
Gypsum, plaster dust, stucco These contain calcium sulfate, a negative interferant. Sulfates present in these materials can interfere with color development.
Chromate Some paints used on metal surfaces (on bridges, in tanks, etc.) contain lead chromate, which is extremely difficult to detect, especially for yellow and orange paints. Chromate is a negative interferant. When a negative result is obtained and there is reason to believe lead chromate is present, it should be confirmed by a certified laboratory or another field technique used. Zinc chromate may also interfere.
Red painted surfaces Red pigment may interfere with a positive surfaces indication (pink color formation). See Section 5 for further discussion.

3. Evaluation Criteria
 

A variety of samples of paint and other materials were collected or prepared. These were then tested using the manufacturer's instructions given for the kit being examined. The appearance of a pink color, indicating the presence of lead at a significant level, was noted for the samples. Lack of response was also noted. Lead content in the samples was confirmed by sample analysis using established OSHA SLTC analytical methods ID-125G (ICP) and ID-121 (AAS) to determine if the results from the kit tests met the HUD conditions (a positive response if the lead content was >0.5% by weight, a negative response if it was <0.5%). Some of the glass and metal samples were also qualitatively or semiquantitatively screened by XRF using OSHA Method ID-204.


4. Test Sources for Lead
 

Paint samples were tested along with a few other materials of interest. The sources of these samples are listed as follows:
  1. Paints which were painted or sprayed onto wood or galvanized steel.
  2. Paint from painted wood or plaster from homes.
  3. Lead metal, lead-containing glass, lead chemicals.
  4. Non-lead solder and metals used in solder other than lead (antimony, tin).
  5. Surfaces in plastic Petri dishes which had films consisting of a readily soluble lead compound with surface concentrations of 0.1 to 2.4 mg/cm2.


5. Lead Test Equipment
 

Manuals for each kit must be consulted before use. The tests done on the various materials were performed according to the manufacturer's instructions supplied in each kit.

LEAD CHECK(TM) Test Kit (HybriVet Systems, Inc.) (10.13.):

The contents of each kit are listed in Table 1. Each Lead Check swab contains two ampoules of chemicals; however, the composition of these chemicals is not given.

For all testing applications, the following steps are used to activate each swab:
  1. CRUSH - With the swab tip pointing up, squeeze and crush points marked "A" and "B" located on the barrel of the swab.
  2. SHAKE AND SQUEEZE - With the swab tip pointing down, shake twice and squeeze gently until the yellow liquid appears on the swab tip - the swab is now activated for testing.
  3. RUB - While squeezing gently, rub the swab tip on the test area for 30 sec.
If the swab turns pink, the test is positive and lead is present. If the swab indicates no color change, the test is negative and no leachable lead has been detected. All negative results must be confirmed using the Test Confirmation Card. If the swab does not turn pink after testing, rub the swab tip on one of the unused test dots on the card. If a pink or red color appears on either the dot or swab, a negative result is substantiated. If the test dot and/or swab does not turn pink or red, the test was invalid and must be repeated with a new swab. All testing, including any necessary confirmation card testing, must be completed within two min.
CAUTION: The test dots on the Test Confirmation Card contain minute amounts of lead. Do not touch these areas. Wash hands after each use.

Procedure for examining painted wood or metal surfaces:
  1. Clean and remove all dust and dirt from the area to be tested.
  2. With a clean knife or scraper, cut a small ¬ in notch at a diagonal to expose all painted layers down to the bare surface - lead may be present in any layer of paint.
  3. Activate a swab.
  4. Rub the activated swab in the exposed cross-section for 30 sec. If any layers contain lead, a positive result will occur - The swab or surface will turn pink.
NOTE: With certain paints, lead is difficult to extract, and it may take longer for positive results to develop. Examine the test surface 30-60 min after the test has been performed before assuming a test result.

NOTE: "Bleeding" may occur when testing surfaces that are painted red. Moisten cotton-tipped applicators with a few drops of distilled white vinegar. Rub the moistened cotton on the red surface. If a red color appears on the cotton, Lead Check Swabs cannot be used. Send a sample of the material to a certified laboratory or use another type of field procedure for further testing.

Procedure for examining lead-containing ceramics or glass:
  1. Activate the swab.
  2. When testing ceramics, rub the swab over all patterns with different colored glazes and any cracks or chipped areas. If lead is leaching from the surface, the swab will turn pink.
  3. When testing glass, rub the swab over the surface.
  4. When testing lead crystal, rub the swab on the inside surface of the glass or other vessel.
Procedure for examining solder (plumbing, food cans):
  1. Wipe off the solder joint with a paper towel or cloth.
  2. Using an emery board or sandpaper, lightly score the surface to be tested.
  3. Activate the swab.
  4. Squeeze one drop of yellow liquid from the swab onto the solder surface.
  5. Touch the swab to the wet solder surface and rub gently for only 10 sec or less.
  6. The swab will turn pink if the solder contains greater than 2% lead.
Procedures for examining lead in dust:
  1. Activate the swab.
  2. Rub activated the swab in the dust for 30 sec. If the dust contains lead, the swab will turn pink.
NOTE: Avoid rubbing the swab into large amounts of "dirt dust" as this will obscure the color test results on the swab.

LEAD ALERT(TM) All in One(TM) Professional Kit (Sensidyne) (10.14.):
Two types of kits are available. The contents of each type of kit are listed in Table 1. The Indicating Solution contains rhodizonate ion which reacts with lead to give a pink color (10.12.); the composition of the Leaching Solution is not given. For recovering paint down to the base material from painted objects, a kit containing a Coring Tool and cleaning brush is available for use with the Lead Alert Kits (see Table 1). The initial preparation and testing of the Indicating Solution takes about 10 min. Most tests take about one to three min to perform.

Procedure for activating the indicating solution:
  1. Remove the red cap from the "Indicating Solution" bottle.
  2. Carefully remove the dropper insert by rolling/twisting it off the bottle.
  3. Open the foil package and place the Indicating Tablet into the bottle of solution.
  4. Replace the dropper insert and the red cap. Tighten the cap and shake the bottle for one min.
  5. Allow the bottle to stand for 5 min, then shake it again until the solution turns yellow. The tablet will not completely dissolve; however, this is normal. The Indicating Solution is now ready for use. (For reference purposes, write the date on the bottle when the reagent is activated.)
  6. When testing has been interrupted for more than 15 min, shake the indicating solution vigorously again for 5-10 sec before resuming testing. When the testing has been interrupted for several hours or days, shake the indicating solution for 30 sec and perform a Positive Control Test before resuming testing.
Procedure for carrying out the Positive Control Test to verify the effectiveness of the testing system:
  1. Place one drop of the Leaching Solution on the Positive Control Strip in the center of one of the numbered circles.
  2. Let it sit for 10 sec, then add one drop of the activated Indicating Solution.
  3. A pinkish (rose) stain will appear in the circle and indicates the test kit is working properly. If the rose stain does not appear, the activity of the Indicating Solution has expired.
CAUTION: For testing purposes, the areas inside the circles on the Positive Control Strip contain minute amounts of lead. Do not touch these areas. Wash hands after each use. After testing and when dry, put the Positive Control Strip back into its pouch.

Procedure for carrying out a total lead test on paint:
  1. Remove a fresh adhesive-backed collection paper and fold it in half. Apply the paper close to the area to be tested.
  2. Using the coring tool, cut down into the surface. Scrape the paint from inside the circle and place it on the paper. Be sure to remove all layers. Thoroughly clean the coring tool.
  3. Transfer the paint from the paper to a plastic vial. Grind up the paint with a plastic rod for about 10 sec.
  4. Add three drops of Leaching Solution to the vial and grind the contents for another 10 sec. Let the vial sit for 20 sec.
  5. Add three drops of Indicating Solution to the tip of a fresh sample collector. Touch the surface of the liquid in the plastic vial with the tip of the collector.
  6. A pink color on the collector tip indicates lead in amounts greater than the limit of 0.5% by weight of lead.
NOTE: When testing red painted surfaces it is possible that the red paint may "bleed out" into the test surface on the sample collector. "Bleed Out" Test: Look at the liquid above the solid in the vial in Step d. above. If the fluid is red, the sample should be sent to a certified analytical laboratory for further testing or another type of field procedure should be used.

Procedure for carrying out a surface lead test on paint (top layer only):
  1. Apply two drops of Leaching Solution to the tip of a sample collector.
  2. Rub the sample collector tip on the surface to be tested for 10-15 sec.
  3. Add two drops of Indicating Solution to the sample collector tip.
  4. A pink color on the collector tip indicates lead in amounts greater than the limit of 0.5% by weight of lead for the top layer of paint.
Procedure for carrying out the sanding test (when only the top one or two layers of paint are to be sanded or otherwise disturbed in preparation for painting. If more than two layers are to be sanded or otherwise disturbed, use the total lead test described above):
  1. Use a fresh abrasive strip to rub lightly over the painted surface. An area of about 0.5 in(2) is sufficient. Avoid contact with or breathing of dust.
  2. Apply two drops of Leaching Solution to a sample collector tip and rub it over the sanded area.
  3. Add one more drop of Leaching Solution to the paint dust now on the collector.
  4. Leave for 30 sec. Add two drops of Indicating Solution to the same area on the collector tip.
  5. A pink color on the collector tip indicates lead in amounts probably greater than the limit of 0.5% by weight of lead for the layer(s) of paint affected.
NOTE: "Bleeding" may occur when testing surfaces that are painted red. During the sanding test on red paint, examine the surface of the sample collector after the Leaching Solution and paint dust have been added to the tip. If the color does not spread, the red pigment will not interfere with the test. If it does spread, send a sample of the material to be tested to a certified analytical laboratory or use another type of field procedure.

Procedure for determining lead in paint, metal, and dust particles:
  1. Apply two drops of Leaching Solution to a sample collector tip.
  2. Apply a very small amount of fine particles of the target material (ground paint chips, paint dust, house dust, etc.) to the tip of the collector.
  3. Apply one or two more drops of Leaching Solution to the particles on the tip. Wait 30 sec.
  4. Apply two drops of Indicating Solution to the collector tip; watch for a color change.
  5. A pink color on the collector tip indicates lead in amounts probably greater than the limit of 0.5% by weight of lead.
Procedure for plumbing pipes, joints, and fixtures:
  1. Locate an area where water pipes are exposed. Determine if any soldered joints are present.
  2. Sand the pipe and/or solder joint lightly with a fresh abrasive strip.
  3. Apply two drops of Leaching Solution to the tip of a sample collector.
  4. Rub the tip of the collector on the surface to be tested for 10-15 sec.
  5. Add two drops of Indicating Solution to the collector tip; watch for a color change.
  6. A pink color on the collector tip indicates lead in amounts probably greater than the limit of 0.5% by weight of lead.


6. Results
 

Results are compiled from samples taken using six lead check kits and two lead alert kits. Results are dependent on manufacturer quality control practices and may vary from lot to lot.

Lead Paints
Lead Metals, Chemicals, and Glass
Lead-Free Metals
Surfaces in Petri Dishes Containing Lead Ranging from 0.1 to 2.4 mg/cm2


Lead Paints
 

The results of the tests conducted with the lead detector kits on paints freshly applied to wood and galvanized steel surfaces are summarized in Table 3. The paints were allowed to dry for a period of several days prior to testing.

Table 3
Paints Brushed or Sprayed onto Wood or Galvanized Steel (Metal)
 
Paint
 		 Surface Lead Test results(1,2) Lead Alert results(3) ICP Anal., Wt.%(4,5)
Sherwin Williams Automotive Finishes Sunfire 421 Acrylic Urethane Enamel(6,7,8) wood min pink(9)
1 none
5 very faint
25 very distinct		 no pink even after
30 min(10)		 Pb 7.8
Cr 1.7
metal 3   none
8   tinge
25 faint
37 distinct
57 darker		 min pink
1 none
23 poss. faint pink		  
Dutch Boy Instant Gold Spray Enamel, Gold 4100 wood no pink no pink Pb 0.09
Zn 16
Cu 39
metal no pink, difficult to determine no pink
DAP Derusto Epoxy Appliance Hi-Gloss Enamel, 511 White wood no pink no pink Pb 0.00
metal no pink no pink  
Spray Enamel, DA 1632 Light Green wood no pink no pink Pb 0.00
Fe 1.7
metal no pink no pink
Pactra Coatings Everyday Spray Paint, N4 Flat White wood no pink no pink Pb 0.00
Sprayon Omnipak LA-16 15216, 5338 White wood no pink no pink Pb 0.08
metal no pink no pink  
Sprayon Industrial Primer Surfacer, 00341 Light Gray wood no pink no pink Pb 0.00
Fe 1.2
Ba 0.00
metal no pink, slight orange no pink
Bright Beauty Spray Lacquer, Clear Plastic Acrylic BB 395 wood no pink no pink Pb 0.00
metal no pink no pink
Enterprise Companies Magic Spray Enamel, Green 09513-30 wood no pink no pink Pb 0.00
Fe 2.7
Champion Sprayon Enamel, Colonial White wood no pink no pink Pb 0.00
DAP Broma 10 Minute Dry Spray Paint, #112 Pink wood (11) (11) Pb 0.19
Illinois Bronze Accent Croft Spray Soft Matte Finish, No. 160 Satinwood wood no pink no pink Pb 0.31
Fe 3.9

Footnote 1 Lead Check Swabs which indicated a negative result were checked with the positive test strip; all reacted positive to the strip.

Footnote 2 For the Lead Check tests, the swab was rubbed over the paint. No cutting into the paint was done.

Footnote 3 The Lead Alert tests were done using the Sanding Test except where indicated.

Footnote 4 For the ICP analyses, the paints were applied to tared filters and allowed to dry. The filters were then reweighed. Dry weights were used in all calculations. All weights were taken to the nearest 0.1 mg.

Footnote 5 All lead results are reported. Any other elements >1% are also reported. Barium, if analyzed, is reported. Barium was analyzed if orange coloration was observed with the kit reagents.

Footnote 6 The prepared Sunfire 421 Acrylic paint, although capable of being sprayed, was applied to the wood and metal surfaces with a paint brush. The other paints were spray paints and were applied to the wood and metal surfaces by spraying.

Footnote 7 The ICP analysis of the Sunfire 421 Acrylic paint was done on the pigment solution component only. The complete paint mixture requires the addition of two additional components: hardener and a diluent solvent.

Footnote 8 See Table 2 (Interferences). Lead chromate appears to be present. Lead chromate is extremely difficult to detect by these techniques. The chromate appears to interfere with the lead analysis. Also, the orange chromate color could obscure any faint pink color which might be present.

Footnote 9 For Lead Check tests on the Sunfire 421 Acrylic paint on both wood and metal, the paint sample was sanded with sandpaper from Lead Alert Kit, otherwise no pink color was observed. The pink color was slow in developing.

Footnote 10 Lead Alert tests on the Sunfire 421 Acrylic paint on wood were done with both the Sanding Test and the Coring Test; after 30 min, no pink color had developed in either test. The test of the paint on metal was done with the Sanding Test; a faint pink color was slow in developing.

Footnote 11 Upon testing the DAP Broma #112 Pink paint, a shade of pink was observed which appeared characteristic of the color of the paint itself. The color was different from the pink normally observed when lead was present. The results of the tests carried out on paint coatings on wood and plaster samples from two homes in the Salt Lake City, UT area are summarized in Table 4.

Table 4
Paints Obtained from Painted Wood or Plaster from Older Homes
 
Paint source Lead Check results(1) Lead Alert results ICP Anal., Wt.%(2)
Garage (Green paint) (Home #1)(3) Cut made at angle into paint- intense pink--Pealed paint, side next wood- intense pink Total lead test- immediate dark pink color on swab Pb 3.1
Zn 14
Surface test- immediate distinct pink on swab Surface test- immediate distinct pink on swab(4)
Garage siding (white paint) (Home #1) Cut made at angle into pain-intense pink Total lead test- immediate dark pink color on swab Pb 3.6
Zn12
Surface test after cut made at angle into paint-intense pink
Surface test only- immediate distinct pink on swab(4)
Baseboard (Home #1) (5) Cut made at angle into paint-three tests were performed; two tests showed no pink, one test showed intense pink on the wood and pink on the swab Total lead test; no pink color observed on swab Pb 0.12
Zn 1.4
Uncut paint-no pink color
Paint chips from fence (Home #1) (5) Surface test, side of paint formerly toward wood (dirty), cleaned with wet wipe-distinct pink Total lead test(6), no pink color observed on swab Pb 0.03
Zn 3.0
Surface test, side of paint formerly toward wood (dirty), cleaned with wet wipe-faint pink, obscured by dirt
Surface test, side of paint away from wood-no pink Surface test, side of pain away from wood- no pink color observed
Paint chips from bottom of doorpost outside living room door (Home #2) (3, 5) Surface test, side of paint formerly toward wood (green)-pink patches on paint Total lead test(6), no pink color observed on swab Pb 0.14
Zn 6.9
Surface test, side of paint formerly toward wood (green)-faint but distinct pink on swab
Surface test, side of paint away from wood (white)-no pink Surface test, side of paint away from wood (white)-no pink, even after 15min(7)
Paint chips from hallway plaster (Home #2) (8) Surface test, side of paint formerly toward plaster (light blue) -no immediate pink; after 15 min, slight pink border Surface test, side of paint formerly toward plaster (light blue)- no pink, even after 15 min(7) Pb 0.24
Surface test, away from plaster (white)- no pink Surface test, side of paint away from plaster (white)-no pink, even after 15 min(7)
Old piece of white painted wood found in back yard (surface cleaned with wet wipe) (Home #2) Cut made at angle into paint-no pink; after 30 min, test spot was light orange Total lead test-no pink, even after 15 min Pb 0.00
Zn 3.5
Ba 0.00

Footnote 1 Lead Check Swabs which indicated a negative result were checked with the positive test strip; all reacted positive to the strip.

Footnote 2 All lead results are reported. Any other elements >1% are also reported. Barium, if analyzed, is reported. Barium was analyzed if orange coloration was observed with the kit reagents.

Footnote 3 Home #1 was ~50 years old; Home #2 was ~40 years old.

Footnote 4 Paint had fine cracks in it. The testing solution may have penetrated to deeper layers.

Footnote 5 Conclusion: Lead was present in the deepest layers of paint but not in the surface layer. Lead-free paint had been applied over paint containing lead. In one of the Lead Check tests on the baseboard, possibly more of the lead-containing layer was exposed than in the other two tests.

Footnote 6 Sample was collected by laying a paint chip on a Collection Paper and cutting a disk for analysis with the Coring Tool.

Footnote 7 The extra time in these Lead Alert tests was taken to observe if the initial apparent negative results were actually indicative of a low lead content or if the color was slow in developing. In all these cases, no color development was observed with increasing time, and therefore these appeared to be true negative results. It thus appears that in most Lead Alert tests when interferences are not present, a positive or negative result will be apparent within a few min.

Footnote 8 If gypsum was present in the plaster, this could have interfered with the surface lead tests on the paint formerly next to the plaster. For the Lead Check test carried out on this paint, the slight pink color was slow in developing.


Lead Metal, Chemicals, and Glass
 

The results of the tests carried out with the lead detector kits on lead metal (both powder and sheet) and lead-containing chemicals and glass are summarized in Table 5.

Table 5
Lead Metal, Lead Chemicals, Lead-Containing Glass

Item
 		 Lead Check results(1)
 		 Lead Alert Results
 		 AAS Anal. Wt.%(2)
 
Powdered lead metal Swab touched to powder-instant intense pink on swab Instant pink, very dark in a few sec(3)  
Lead sheet Immediate pink Immediate pink  
Lead chromate No pink observed over orange color(4,5) No pink observed over orange color(3,5)  
Lead sulfate Definite pink(4) Intermediate pink(3)  
Lead sulfide No pink, even after 10 min(4) Pink(3)  
Lead dimethyldithiocarbamate Definite pink(4) Very small amount of pink; small particles turned darker pink with time(3)  
Lead methylmercaptide Immediate pink(4) Dark pink(3)  
Lead crystal bowl (24% PbO-Manufacturer's specification) Inside bottom cleaned with tissue dampened with deionized water- no pink observed in swab solution on bowl bottom or on swab(6) Inside bottom cleaned with tissue dampened with deionized water-no pink observed on swab(7)  
Micro Cover Glasses Van Waters and Rogers, Inc. No. 1 thickness, CAT 483-93 24 60 mm (X-ray fluorescence showed no Zn, a little Pb) No pink(6) No pink(7) Pb 0.18
Micro Cover Glasses Van Waters and Rogers, Inc. No. 1 thickness, No. 48366-045 18mm square (X-ray fluor: some Zn, some Pb) No pink(6) No pink(7) Pb 0.48
Microscope Cover Glasses Erie Scientific Portsmouth, NH (ESCO) No. 1« thickness, 22 22 mm  (X-ray fluor: some Zn, trace As, no Pb) No pink(6) No pink(7) Pb 0.01

Footnote 1 Lead Check Swabs which indicated a negative result were checked with the positive test strip; all reacted positive to the strip.
Footnote 2 Samples were initially digested with hydrofluoric acid to remove silica. Lead results are reported.

Footnote 3 Paint, metal, and dust particles procedure was used.
Footnote 4 Dust test procedure was used. The activated swab was rubbed into the powdered chemical.
Footnote 5 See Table 2 (Interferences). Lead chromate is extremely difficult to detect by these techniques. The chromate appears to interfere with the lead analysis. Also, the orange chromate color could obscure any faint pink color which might be present.
Footnote 6 Ceramics and lead crystal procedure was used. The product literature indicates that 1-2 ug of leachable lead can be detected.
Footnote 7 Surface test procedure was used.


Lead-Free Metals
 

The results of the tests carried out with the lead detector kits on lead-free metals (non-lead solder and metals used in these types of solders such as antimony and tin) are summarized in Table 6. The purpose of these tests was to determine if any of these metals would give a positive pink reaction with the test procedures.

Table 6
Non-Lead Solder and Metals Used in Solder Other than Lead (Antimony, Tin)
Metal Lead Check results (1, 2, 3) Lead Alert results(4)
Oatey Safe Flo(TM) Silver Lead Free Plumbing Solder(5) No pink No pink
Antimony metal (solid piece) No pink No pink; only a yellowish brown coloration
Tin metal (solid piece) No pink No pink; only a yellowish brown coloration

Footnote 1 Solder (Plumbing and Food Cans) test procedure was used. Sandpaper from Lead Alert Kit was used for sanding.

Footnote 2 If too much metal dust was picked up on the swab, a purplish color was obtained which could easily have obscured a small amount of pink color. The observations reported here were made under conditions where the metal dust collected on the swab was small enough not to obscure any pink color which might have been present.

Footnote 3 Lead Check Swabs which indicated a negative result were checked with the positive test strip; all reacted positive to the strip.

Footnote 4 Plumbing Pipes, Joints, and Fixtures test procedure was used.

Footnote 5 The following X-ray fluorescence analysis data were obtained for the solder:
Metal Concentration % Rel. Error
(1-sigma)
Cu 1.37 Wt% 4.15
Ag 820.91 ppm 7.52
Sn 97.61 Wt% 0.09
Bi 0.94 Wt% 2.51
  100.00 Wt%  


Surfaces in Petri Dishes Containing Lead Ranging From 0.1 to 2.4 mg/cm2
 

As mentioned previously, the HUD Interim Guidelines action level for lead based paint is a lead content of 1.0 mg/cm2 as measured by an XRF analyzer or, when using chemical testing, it is either 0.5% by weight or 1.0 mg/cm2 (10.9.). In the study reported by Pace Environs on 243 paint samples, the Lead Alert Test Kit very satisfactorily met the conditions necessary to meet HUD performance standards for lead tests, as far as the 0.5% lead content (determined by AAS) was concerned. In a comparison study using a laboratory XRF instrument, the XRF surface measurements for mg/cm2 compared well with the AAS determinations except for three samples near the 1 mg/cm2 amount (>1 mg/cm2 lead by lab XRF but >0.5% lead by AAS) (10.12.).

In a test to determine the response of the kits to various levels of surface lead, a series of plastic Petri dishes containing soluble lead films were prepared by adding various amounts of a solution of lead nitrate in water to each of several dishes. Surface coatings of 0.1, 0.6, 1.0, 1.4, and 2.4 mg/cm2 of lead were prepared. The solution was then evaporated. Since the solution tended to form liquid beads during evaporation, isopropanol was added to assist in spreading the solution over the surface of the Petri dish bottom to obtain as nearly a uniform spread as possible while evaporation was proceeding. The deposits, however, did not appear very uniform.

Both kits showed positive pink results when the swabs were applied to the 0.1 mg/cm2 surface. No pink response should have been observed until amounts near or above 1.0 mg/cm2 were tested, in order to meet the HUD conditions discussed above. Evidently the loosely held lead in this experiment does not correspond to the much more tightly bound lead in paint that the kits are designed for, and thus it reacts more readily with the kit indicating solutions. Therefore, this experiment using loosely held layers of lead does not constitute a rigorous experiment.

7. Observations and Evaluation of Performance of the Lead Detector Kits
 

During the course of the work with the Lead Alert Kit, it was found that the Indicating Solution occasionally needed longer vigorous shaking times than specified in the instructions to be fully activated. This was the case both upon initial activation after first adding the pill to the solution, and activating the solution after it had been standing for some time. If the pink stain formed in the Positive Control Test is very faint, the solution should be shaken vigorously for an additional minute and then be tested again.

Chromate interference can be a serious problem in lead analysis. In the case of the Sunfire 421 Enamel, which contained a large amount of lead and also a significant amount of chromium presumably present as chromate, no positive result for lead was obtained on a surface test unless the paint was sanded, and then the pink color was very slow to develop. The pink color in the Lead Alert test on metal was very faint. No pink color was observed with the Lead Alert total lead (coring) test. The Lead Check tests gave comparable positive responses on wood and metal substrates; however, the paint needed to be sanded before testing, and the pink color was very slow in developing. The faint pink color tended to be obscured by the orange color present. No pink color was observed with the test on lead chromate powder.

In two of the tests performed (on the Sprayon Industrial Primer Surfacer 00341 and the old piece of white-painted wood in the Home #2 back yard), a light orange color was obtained. Barium is sometimes present in paint, and so these paints were analyzed for barium. However no barium was found. The reason for the orange color obtained in the lead tests was unknown.

In Table 3, the paints indicated were dispensed from spray cans except for the Sunfire 421 Enamel, which was mixed according to instructions and applied with a paint brush. All of the spray paints showed lead contents <0.5% upon ICP analysis, and all gave negative results with both test kits for wood and metal surfaces. In Table 4, tests on surfaces containing an overall lead content of well above 0.5% indicated that both the initial and final layers of each paint sample contained significant lead, although the tests on each final layer are questionable since there were fine cracks in these layers. Surface tests on paint samples containing some lead but at an overall content of <0.5% gave positive tests on the initial layer but negative results on the outside layer; evidently the substrate had been initially painted with lead-containing paint but had later been painted over with paint containing little or no lead, thus reducing the overall lead content of the entire painted surface. This "diluting" of the lead-based painted surface with no-lead paints is typical for many painted surfaces in existence. The results obtained with the Lead Alert Kit using the Total Lead (Coring) test gave positive results for paint containing an overall content of >0.5% lead and negative results for paint containing an overall content of <0.5% lead, thus meeting the HUD requirements. The results and observations tend to indicate that in the Lead Alert tests when interferences such as chromate are not present, a definite positive or negative result will be apparent within a few min, as no change in color was observed with time. The Lead Check test involving cutting into the paint to expose all layers appears designed to give a positive test if any layer contains significant lead; however, the paint must be cut into at a sharp angle with respect to the surface so that all layers are adequately exposed. As mentioned previously, the product literature indicates that 1-2 ug of leachable lead can be detected (10.7.). Interference from plaster on the tests appeared to be evident in paint chips recovered from a plastered surface. The outer layer gave negative tests with both kits for lead, and these results should be correct; however, the tests on the inner layer (originally next to the plaster) indicated a negative Lead Alert test result and a questionable positive Lead Check test result (a slight pink border slowly developed). Since the paint had an overall lead content of 0.24%, the conclusion was reached that the inner layer may have had a significant amount of lead but it could not be detected because of interference from gypsum in the plaster. Lead metal and lead chemicals all gave positive results with the kits except for lead chromate with both kits and lead sulfide with the Lead Check Kit (Table 5). The problems with lead chromate have been discussed previously; the reason for the lack of response of lead sulfide to the Lead Check Kit is unknown, except that it may be due to the low solubility of lead sulfide. Lead-free metals, including antimony, tin, and a lead-free solder, were tested with the kits to ensure these metals would not give false-positive test results for lead (Table 6). Both kits gave negative results for these tests, and thus they can reliably distinguish lead from antimony and tin which are often used in lead-free solders. Several lead-containing glasses were tested with these kits (Table 5). Both kits gave negative results. Evidently the lead is so tightly bound as the silicate that it is extremely insoluble, and thus these glasses apparently do not constitute a significant lead hazard.


8. Recommendation
 

Both kits perform satisfactorily and are capable of identifying lead at the levels given in the Lead Exposure Reduction Act (October 29, 1992) (10.8.) and the Department of Housing and Urban Development (HUD) Interim Guidelines (September, 1990, revised May 1991) (10.9.). For testing paint in which both lead-free and lead-containing paint are present, the Lead Alert Total Lead (Coring) test appears to give appropriate positive and negative results within the HUD requirements (whether greater or less than 0.5% lead by weight). With the Lead Check tests, cutting into the paint to expose all layers will make it possible to determine if any layer has an amount of lead greater than that allowed in the HUD requirements.

Both kits can be used by OSHA for the purposes indicated by the manufacturers provided the following are adhered to:

1. A positive indication should normally indicate lead is present, and the OSHA CSHO should consider air sampling or exposure control if necessary.

2. A negative indication does not necessarily indicate the absence of lead. If doubt exists regarding the negative value, available bulk material should be submitted for laboratory analysis using spectroscopic techniques or another field procedure should be used.

3. Although lead may be present, an assessment will still need to be made by the OSHA CSHO to determine whether an occupational hazard can or will exist.

4. For the Lead Check test involving cutting into the paint to expose all layers, the paint must be cut into at a sharp angle with respect to the surface so that all layers are adequately exposed.

5. In work with the Lead Alert Kit, the Indicating Solution occasionally may need longer vigorous shaking times than specified in the instructions to be fully activated, both upon initial activation after first adding the pill to the solution, and activating the solution after it has been standing for some time. If the pink stain formed in the Positive Control Test is very faint, the solution should be shaken vigorously for an additional minute and then be tested again.

6. Most tests will be complete in ~2 min; however, when interferences are present, it may require 15-20 min for a pink color to become apparent.

7. Chromate is a serious interferant in both kit tests. Also, lead as lead sulfide could not be detected by the Lead Check Kit.


9. Additional Observations
 

These kits have been designed not only to detect lead in intact paint, but they also have been designed to detect lead in house dust. There is evidence that most lead exposure in homes is related to dirt brought in from the outside (10.15.), and lead-containing dust is the main route for lead poisoning in children (10.13.). However, lead poisoning has also occurred in children from eating loose paint chips. Intact lead paint should be left alone or be painted over, but if it is to be removed, precautions must be taken. Indiscriminate removal of lead will present a situation similar to that noted with asbestos (10.15.). There are no Federal standards governing the level of lead in house dust at present. The States of Maryland and Massachusetts have established the following standards for lead in dust on specific interior surfaces (10.9.):

Floors 200 µg/ft(2)
Window Sills 500 µg/ft(2)
Window Wells 800 µg/ft(2)

Lead-contaminated dust on surfaces may also be collected on commercial wipes for examination using laboratory analysis (10.9.). Sensidyne has a Wipe Sample Test Kit (Catalog No. 225-2401) available for carrying out these tests (10.7.). A cyclone device to be used in conjunction with vacuuming of settled dust has recently been described to address exposure problems associated with lead-containing dusts; this device appears to have high dust recoveries and more consistent recoveries across particle sizes and dust loadings and higher precision across replicate samplings than previous devices (10.16.). A sodium sulfide test for lead is available for tests on skin and other surfaces (10.4.); however, in work for HUD by Dewberry and Davis in 1989, their report concluded that this methodology is unsatisfactory for screening lead present in painted surfaces using HUD action level guidelines (10.12.).

Problems with portable XRF instruments have occurred. One problem is the uncertainty existing in the analysis of paint samples where the lead content is very close to the HUD action level of 1.0 mg/cm(2)(as discussed earlier) (10.9.). A new field method employing a portable XRF instrument with a high resolution (cooled) semiconductor detector for the analysis of lead in paint and soil has been developed and reported (10.17.). Portable XRF instruments are valuable in lead detection and analysis in the field, but they are also expensive. Also, safety and training considerations need to be made.

The lead detector kits described in this report remain as inexpensive, reliable, and easy to use devices for lead identification provided potential interference precautions are taken.

10. References
 

10.1. Anderson, L.A., Jr.: Developing an Effective Lead Detection and Abatement Industry: The Role of the Industrial Hygienist. Am. Ind. Hyg. Assoc. J.54: 331-334 (1993).

10.2. Ashley, K. and M.E. McKnight: Lead Abatement in Buildings and Related Structures. ASTM Standardization News: 32-39 (December 1993).

10.3.Lawrence, K.L.: Worker Protection from Lead Exposure. Job Safety and Health Quarterly: 24 (Summer 1993).

10.4. Smith, R.B.: Building a New Lead Standard. Occupational Health and Safety: 32-38 (February 1993).

10.5. The News on Lead. UC Berkeley Wellness Letter: 4-6 (November 1993).

10.6. Rekus, J.F.: A Blueprint for Lead Hazards. Occupational Health and Safety: 24-37 (January 1994).

10.7. SKC: Lead Abatement and Monitoring. Eighty Four, PA: SKC, August 1, 1993.

10.8. "Residential Lead-Based Paint Hazard Reduction Act of the Housing and Community Development Act of 1992," Public Law 102-550 Title X, 1992. pp. 106 STAT. 3897-3927.

10.9. U.S. Department of Housing and Urban Development: Lead Based Paint: Interim Guidelines for Hazard Identification and Abatement in Public and Indian Housing. Washington, DC: U.S. Government Printing Office, 1990 rev. 1991. pp. 1-161, Appendices.

10.10. "Lead," Code of Federal Regulations 29 CFR (7-1-90 Ed.), Pt. 1910.1025, 1991, pp. 156-194.

10.11. "Lead," Code of Federal Regulations 29 CFR (6-24-93 Ed.), Pt. 1926.62, 1993, pp. 186-223.

10.12. Pace Environs, Inc.: Comparing Test Results for Lead-Based Paint on Painted Surfaces. Using Four Different Methods. Cary, NC: Pace Environs, Inc., January 8, 1993.

10.13. HybriVet Systems, Inc.: Lead Check(TM) Swabs Lead Test Kit Instruction Manual. Framingham, MA: HybriVet Systems, Inc., 1992.

10.14. Sensidyne, Inc.: Lead Alert(TM) Easy to Use Professional All in One Test Kit. Clearwater, FL: Sensidyne, Inc., 1993.

10.15. Thomas Klingner: "Considerations to be Taken into Account Regarding Exposure to Lead and other Toxic Materials." March 14, 1994. [Private Conversation]. Thomas Klingner, Colormetric Laboratories, 1261A Rand Road, Des Plaines, IL 60016.

10.16. Farfel, M.R., P.S.J. Lees, D. Bannon, B.S. Lim, and C.A. Rohde: Comparison of Two Cyclone-Based Collection Devices for the Evaluation of Lead-Containing Residential Dusts. Appl. Occup. Environ. Hyg. 9:212-217 (1994).

10.17. Driscoll, J.N., C. Wood, T. Powell, and J.S. Askew: An Extractive X-Ray Fluorescence Method for Field Screening Lead Paint Sites. Appl. Occup. Environ. Hyg. 9:206-211 (1994).

 
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