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The Michigan Department of Community Health (MDCH) Division of Environmental and Occupational Epidemiology (DEOE) assisted the Kent County Health Department (KCHD) with a potential case of cyanide poisoning. Industrial hygienists and occupational health physicians from the Michigan Occupational Safety and Health Act (MIOSHA) program and the National Institute for Occupational Safety and Health (NIOSH) also participated in the investigation.

On November 6, 2001, the KCHD received a call from an area hospital to report an apparent case of cyanide poisoning. A 32-year-old male was admitted to the Emergency Room (ER) on November 4, 2001, complaining of severe gastro-intestinal distress, malaise, vomiting, sweats, and a numbness or paralysis in his extremities and hips. The attending ER physician observed low blood pressure, fever, rapid breathing, tachycardia, mottled coloration, and peripheral cyanosis. Based on these symptoms, the ER physician ordered a series of blood tests, which included cyanide. Results showed the patient had levels of cyanide and thiocyanate, the primary metabolic byproduct of cyanide, in his blood at 72 nanograms per milliliter (ng/ml). Treatment reduced these levels to around 50 ng/ml. The reference range for blood cyanide used by the hospital laboratory was 0-16 ng/ml. Therefore, the hospital laboratory characterized blood cyanide levels >16 ng/ml as elevated.

The patient reported working all day in the basement of the 100-year-old, 30,000-square-foot building he owns at 620 Century Street, Grand Rapids, Michigan. The building was used for industrial purposes for many years before being converted to office space. At the time of this incident, the building housed several commercial tenants, most notably a telephone switching station on the third floor. Collectively, about 40 people worked in the building. The patient noted dust from the work area had accumulated on his work jersey. Before going home, the patient shook out the jersey to remove as much of the dust as possible. At home he hugged his two children with the jersey on, and then removed it before greeting his wife. He began experiencing symptoms shortly after returning home and was driven to a nearby hospital emergency room.

The patient also reported his son had been vomiting on and off for about four days. Subsequent testing of his immediate family showed both his children had elevated, but sub-toxic, levels of cyanide and thiocyanate in their bloodstream. Non-detectable concentrations of cyanide were found in his wife's blood. Additional blood tests revealed that the patient's business partner, who worked closely with him, also had elevated levels of cyanide and thiocyanate.

A KCHD epidemiologist interviewed the index patient on November 6, 2001, documenting information germane to an epidemiological investigation such as time of symptoms onset, recent activities, workplace habits, obvious exposures, and dietary history. At the early stages of this incident, KCHD was concerned about a possible link to a terrorism incident and proceeded accordingly. KCHD contacted MDCH's bioterrorism unit, which did not believe this case was related to bioterrorism and referred them to DEOE.

On November 9, 2001, KCHD quarantined the building and re-located the family from their residence until tests could rule out cyanide as a significant contaminant at either location. That night, staff from DEOE, KCHD, and the Grand Rapids Hazardous Materials Team assembled at the worksite to collect environmental samples. DEOE staff and two members of the Grand Rapids Hazardous Materials Team entered the building and collected 36 wipe samples (100 square centimeters each). Sampling occurred on all floors of the building with an emphasis on the basement, where the patient had been working prior to the onset of symptoms. DEOE staff also entered the residence to collect two work jerseys, a pair of shoes, and a bathroom towel for laboratory extraction and analysis (Table 1).

On November 12, 2001, KCHD received the test results for 620 Century Street; all 36 wipe samples were negative. The analysis methodology was a colorimetric test capable of detecting as little as 80 nanograms of cyanide per sample. KCHD cleared 620 Century Street for re-occupancy on November 13, 2001. A qualitative analysis of the work jersey taken from the home showed low, but detectable concentrations of cyanide salts. As the cyanide found on the work jersey was low and unrelated to the family's residence, KCHD cleared the residence for occupancy on November 15, 2001.

The index patient, and building owner, hired an independent laboratory to take one additional sample of the sandblasting matrix (blasting sand plus brick powder) in his basement office at 620 Century Street on November 16, 2001. Results showed the matrix contained 420 micrograms cyanide per kilogram of matrix (parts per billion).

MIOSHA collected 22 wipe samples, 2 bulk analysis samples, and 2 air samples that tested for gaseous hydrogen cyanide and airborne cyanide particulates, from 620 Century Street on November 30, 2001 (Table 1). Six of the 22 wipe samples had detectable concentrations of cyanide salts, all <0.005 nanograms per wipe. Results from the two bulk samples taken from brick columns in the basement were 1.1 parts per million (ppm) and 17 ppm. Both air samples were non-detects.


Environmental Contamination

None of the results from any environmental sample collected at 620 Century Street or the home showed sufficient cyanide to cause adverse health effects. The highest concentration of cyanide found during this investigation, 17 ppm of cyanide in a MIOSHA bulk analysis, is contrasted against the Michigan Department of Environmental Quality's "Direct Contact" Cleanup Criteria (Part 201) for cyanide in commercial soils of 250 ppm. In all, 63 samples were collected from the indoor environment of 620 Century Street; the majority of analyses were for powder or particulate forms of cyanide, such as cyanide salts. These sampling results do not indicate that significant concentrations of cyanide or cyanide salts are present at the worksite.

Table 1. Cyanide concentrations (varied media), Grand Rapids, Michigan

Sample medium and location Testing agency/laboratory  
KCHD/MDCH Triad Env. MIOSHA Comparison Values
36 wipe samples (100 cm2 each) from 620 Century SW (11/9/2001) Non-detect     250 ppm(1)
Work jersey from home; qualitative extraction analysis (11/9/2001) Trace     250 ppm
Sandblasting matrix at 620 Century SW (11/16/2001)   420 ppb   250 ppm
22 wipe samples 620 Century SW (11/30/2001):
6 positive results
    equipment bay: 0.0044 ng/wipe
equipment bay: 0.0032 ng/wipe
conference table: 0.0018 ng/wipe
office area: 0.0045 ng/wipe
furnace filter: 0.0031 ng/wipe
office beam: 0.0094 ng/wipe
250 ppm
2 bulk samples (brick column) (11/30/2001)     17 ppm
1.1 ppm
250 ppm
2 air samples (hydrogen cyanide gas and airborne cyanide salt particulates) (11/30/2001)     Non-detect 5 mg/m3(2)
* Michigan Department of Environmental Quality Direct Contact Cleanup Criteria for Commercial Soils
Occupational Safety and Health Administration 8-hour Permissible Exposure Limit

Human Exposure Pathways

People can be exposed to cyanide through all three major pathways: inhalation, ingestion, and dermal contact. Air, water, food, or soil containing cyanide can all contribute to an overall cyanide exposure. Cigarette smoke also contains cyanide.

Toxicological Evaluation

Occupational health physicians from MIOSHA and NIOSH concluded that the reference range used by the hospital laboratory for cyanide was not correct. A literature review yielded several articles that showed that the average concentration of blood cyanide in the general population was around 125 ng/ml and may range as high as 400 ng/ml (two standard deviations from the mean) with symptoms of cyanide poisoning generally not appearing until around 500 ng/ml in most people. The 70 ng/ml found in the index patient was well within normal limits.

The physicians observed that cyanide poisoning is not associated with fever or vomiting and concluded that the patient's symptoms, and that of his son, were more likely the result of a gastro-intestinal sepsis than cyanide poisoning. Both physicians recommended a clarification of the existing blood cyanide reference range used by hospital laboratories.


The building at 620 Century Street was used for industrial purposes for several decades before being converted to office space. The building houses several commercial tenants, most notably a telephone switching station on the third floor. Collectively, about 40 adults of varying age and ethnicity work in the building.


Environmental samples collected from 620 Century SW by KCHD and MIOSHA over a three week period showed low levels of cyanide that were unlikely to cause any adverse health effects. Levels were below the Michigan Department of Environmental Quality's Direct Contact Cleanup Criteria (Part 201) for cyanide in commercial soils of 250 ppm. KCHD granted re-occupancy of 620 Century Street on November 13, 2001 and for the residence on November 15, 2001, after results showed non-significant levels of cyanide in either structure (Table 1). No public health hazard currently exists at 620 Century Street or the family's residence.


MDCH made the following recommendations:

  1. Isolate people from the indoor environment of 620 Century Street, Grand Rapids, Michigan until analysis of environmental samples confirmed that unsafe levels of cyanide did not exist;

  2. Isolate people from the indoor environment of the family's residence until analysis of items taken from the home confirmed that unsafe levels of cyanide were not present;

  3. Collect needed samples in the workplace and residence to verify the safety of those environments; and,

  4. Contact MIOSHA regarding workplace exposures and safety.

The recommendations listed above were implemented and no further action is necessary at this site.


MDCH carried out the following actions over the course of the investigation:

  1. MDCH communicated with KCHD, NIOSH, and MIOSHA regarding cyanide exposure health effects, environmental limits, and testing methodology throughout the investigation;

  2. MDCH staff worked with KCHD and the Grand Rapids Fire Department's hazardous materials team to the collect 36 wipe samples throughout the worksite on 9 November 2001;

  3. MDCH staff entered the residence to collect several items of clothing for analysis; and,

  4. MDCH contacted NIOSH requesting their assistance in this investigation.


ATSDR (Agency for Toxics Substance and Disease Registry). 1998. Toxicological Profile for Cyanide, Update, Draft for Public Comment.

MDEQ (Michigan Department of Environmental Quality). 2000. Environmental Response Division. Operational Memorandum #18: Part 201 Generic Cleanup Criteria Tables. June 7, 2000. Available at <>.

Clark CJ, Campbell D, Reid WH. 1981. Blood carboxyhaemoglobin and cyanide levels in fire survivors. Lancet. Jun 20;1(8234):1332-5.

Baud FJ, Barriot P, Toffis V, Riou B, Vicaut E, Lecarpentier Y, Bourdon R, Astier A, Bismuth C. 1991. Elevated blood cyanide concentrations in victims of smoke inhalation. N Engl J Med. Dec 19;325(25):1761-6.


Michigan Department of Community Health
Division of Environmental and Occupational Epidemiology

Daniel Lince, M.S., Health Educator

Linda D. Larsen, Ph.D., Toxicologist

ATSDR Regional Representative

Mark Johnson
Regional Services, Region V
Office of the Assistant Administrator

ATSDR Technical Project Officer

Alan Yarbrough
Division of Health Assessment and Consultation
Superfund Site Assessment Branch


This Possible Cyanide Poisoning Investigation Health Consultation was prepared by the Michigan Department of Community Health under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the health consultation was begun.

Alan W. Yarbrough
Technical Project Officer, SPS, SSAB, DHAC, ATSDR

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public health consultation and concurs with the findings.

Richard Gillig
Chief, State Program Section, SSAB, DHAC, ATSDR

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

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