Concise International Chemical Assessment Document 33

Concise International Chemical Assessment Document 33

20

cough. No abnormal symptoms were noted during the

physical examination of seven of the workers;

crepitations dispelled by cough were observed in one

worker (not the same worker reporting an occasional

cough). Pneumoconiosis was detected in the

radiographs of seven workers. Three other workers

employed for 1 month to 1 year were also examined in

1961. Two of these workers reported having slight

coughs, but no abnormal findings were observed during

the physical examination, and the chest radiographs

were normal. The concentration of barium in the dust

was not measured. Barite samples were analysed for

quartz, silica, and iron content. No quartz was detected,

and the total silica and total iron (as iron oxide)

concentrations were 0.07–1.96% and 0.03–0.89%,

respectively.

Ten of the 11 workers examined in 1961 were re-

examined in 1963 (18 months later) (Doig, 1976). Two new

cases of pneumoconiosis were diagnosed. Thus, 9 of 10

workers exposed to barium sulfate for 1.5–19.5 years

(mean 8.2 years) had well-marked baritosis. Three of

these workers reported a slight or occasional cough, and

none had dyspnoea. Among the nine workers with

baritosis, three did not smoke, four smoked 1 pack/day,

and two smoked >1 pack/day. In six of the seven workers

with previously diagnosed baritosis, no significant

changes in the degree of pneumoconiosis were

observed; an increase in the number of opacities was

observed in the seventh worker. Spirometric lung

function tests (vital capacity, flow rate, and forced

expiratory volume) were performed in five workers. For

three of these workers, the results of the lung function

tests were similar to predicted normal values (89–119%

of predicted values). Lung function was below normal in

the other two workers (70–85% of predicted values). It is

questionable whether the impaired lung function was

related to barium exposure. One of the two workers was

an alcoholic and heavy smoker, and the other had a

fibrotic right middle lung lobe that probably resulted

from a childhood illness.

The barite grinding facility closed in 1964, and

follow-up examinations were performed in 1966, 1969,

and 1973 on five of the workers (Doig, 1976). Termination

of barium exposure resulted in a decline in the profusion

and density of opacities. In 1966, there was a slight

clearing of opacities; by 1973, there was a marked

decrease in profusion and density. No significant

changes in lung function were observed during this 10-

year period.

NIOSH (1982) conducted a health survey of past

and present workers at the Sherwin Williams Company’s

Coffeyville, Kansas, USA, facility. Work performed at

the facility included grinding, blending, and mixing

mineral ores. At the time of the study, four processes

were in operation: “ozide process,” which involved

blending several grades of zinc oxide; “ozark process,”

which involved bagging very pure zinc oxide powder;

“bayrite process,” which involved grinding and mixing

several grades of barium-containing ores; and “sher-tone

process,” which involved mixing inert clays with animal

tallow. A medical evaluation was performed on 61

current workers (91% participation). Information on

demographics, frequency of various symptoms

occurring during the previous 2 months, chemical expo-

sure, occupational history, and smoking history, as well

as history of renal disease, allergies, and hypertension,

was obtained from directed questionnaires. In addition,

spot urine and blood samples and blood pressure mea-

surements were taken. Exposures to barium, lead,

cadmium, and zinc were estimated from 27 personal

samples collected over a 2-day period. In the seven

personal breathing-zone samples collected from the

bayrite area, the levels of soluble barium ranged from

87.3 to 1920.0 mg/m

3

 (mean 1068.5 mg/m

3

), lead levels

ranged from not detected to 15.0 mg/m

3

 (mean

12.2 mg/m

3

, excluding two samples in which lead was not

detected), zinc levels ranged from 22.4 to 132.0 mg/m

3

(mean 72 mg/m

3

), and all seven samples had no

detectable levels of cadmium. Soluble barium was also

detected in breathing-zone samples in the ozark area

(10.6–1397.0 mg/m

3

, mean 196.1 mg/m

3

), ozide area

(11.6–99.5 mg/m

3

, mean 46.8 mg/m

3

), and sher-tone area

(114.3–167.5 mg/m

3

, mean 70.45 mg/m

3

).

Two approaches were used to analyse the results

of the health survey (NIOSH, 1982). In the first approach,

the workers were divided into five groups based on

current job assignments. Of the 61 current workers, 14

worked in the bayrite area (mean duration 3 years). No

statistically significant increases in the incidence of

subjective symptoms (e.g., headache, cough, nausea) or

differences in mean blood lead levels, number of workers

with blood lead levels greater than 39 mg/dl, mean free

erythrocyte protoporphyrin (FEP) levels, mean

haematocrit levels, mean serum creatinine levels, number

of workers with serum creatinine levels greater than 1.5

mg/dl, number of workers with blood urea nitrogen

(BUN) levels greater than 20 mg/dl, blood pressure, or

mean urine cadmium levels were observed between the

different groups of workers. In the second approach, the

workers were divided into seven groups based on past

job assignments. One group consisted of 12 workers

working in barium process areas (bayrite process and

other processes no longer in operation at the facility that

involved exposure to barium ores and barium carbonate)

for at least 5 years; barium exposure levels were not

reported for this group of workers. The results of the

health survey for the barium-exposed workers were 

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