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This is the second update of a study of 3,444 taconite miners and millers who were first exposed to taconite, with associated exposures to silica and nonasbestiform amphiboles, in the period 1947 through 1958. Previous analyses of deaths through 1977, and again through 1983, showed no significant excess deaths from any specific causes. The present study continues the follow-up through 1988, adding 14,748 person-years of observation and 261 death certificates for analysis. The population, reduced to 3,431 because of the detection of 13 earlier duplications, has now been observed for 101,055 person-years, with 1,058 deaths and 1,039 death certificates. Death certificates were obtained for 98.2% of those known to be dead. The total number of deaths was significantly fewer than expected. Based on US rates, the standardized mortality ratio (SMR) was 83 (ie, 83% of expected). Based on Minnesota death rates, it was 91. With both US and Minnesota death rates, the SMRs for malignant neoplasms, cancer of the respiratory tract, cancer of the digestive system, heart disease, nonmalignant respiratory disease, and cirrhosis of the liver were all below 100. Slightly elevated SMRs were found for cancer of the colon, cancer of the kidney, and lymphopoietic cancer. These elevations were not statistically significant. Separate analyses were made of total deaths, lung cancer deaths, and kidney cancer deaths in men who had worked with taconite for time periods of less than 1 year, 1-5 years, 5-10 years, and over 10 years, during observation periods less than 10 years, 10-20 years, and over 20 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Methylcyclopentadienyl manganese tricarbonyl (MMT) is effective in raising the octane level of gasoline and is currently used in Canada for that purpose in a maximal concentration of 18 mg Mn/l (slightly less than 0.07 g Mn/U.S. gal). It has been estimated that if MMT were used in all U.S. gasoline in these amounts, the median increase of Mn in ambient air would be not more than 0.05 microgram Mn/m3, with increments generally less than 0.5 microgram Mn/m3 along urban corridors. The scientific literature was reviewed to determine how the increases in environmental manganese predicted from MMT use would relate to the amounts in the natural environment and necessary to life and to the concentrations associated with toxic effects. Even with additional manganese from the use of fuel additives, total Mn intakes would remain within the range of average amounts absorbed from food and water. Respirable manganese in ambient air due to MMT combustion would be many order of magnitude below the concentrations associated with occupational manganism and respiratory problems and also below those reported in isolated episodes of respiratory symptoms in communities near ferromanganese plants. Evidence was reviewed on the possibilities of: (1) increased absorption of inhaled manganese compared with ingested manganese; (2) hypersusceptibility of infants and persons of advanced age; and (3) increased absorption associated with iron deficiency. While relevant to high levels of exposure, these factors would not be expected to lead to toxic effects from the very low concentrations of Mn resulting from MMT use. Experimental animals that inhaled the combustion products of MMT in concentrations of approximately 10, 100, and 1000 micrograms Mn/m3 for 9 mo did not show toxic effects, although there was temporary elevation of tissue levels of Mn. Rhesus monkeys, susceptible to the neurologic effects of Mn, showed no symptoms after inhaling the combustion products of MMT in concentrations of 100 micrograms Mn/m3 for up to 66 wk. Monkeys exposed to 5000 microgram Mn/m3 also showed no symptoms. There is thus a wide margin of safety between the intakes of Mn essential to health and the high concentrations that have been associated with toxic effects. The small amounts of manganese added to the environment by the combustion of MMT used as a fuel additive would be comparable to the normal background and should not create health problems.

The occurrence of several outbreaks of illness among workers handling castor bean pomace at eastern seaports in 1958 and 1959 led to an investigation of the toxicity of a number of commercial preparations. The conventional hemagglutination test and a toxic assay were used to study 14 commercial samples. The agglutination activity may be destroyed by heat without complete destruction of the toxic activity. Four of the samples collected were as toxic as the ricin sample used as the bioassay standard. In view of the potency of the toxin, ricin, and the failure of the agglutinating activity to correlate with the toxic properties of the samples, it is recommended that a toxin assay such as described in this paper be used to evaluate commercial preparations.

Chest roentgenograms of 240 perlite workers employed for 1 to 23 years in the industry, showed no evidence of pneumoconiosis associated with perlite exposures. One individual, found to have simple pneumoconiosis, and one found to have complicated pneumoconiosis, had formerly been diatomaceous earth workers. Since only 28 of the men had been in the industry over 15 years and only seven for 20 years or more, continued surveillance is essential to make sure that there are no effects with more prolonged exposures. Studies of pulmonary function of the individuals who have had relatively long exposures are needed to supplement radiographic evidence.

This report is based on an analysis of deaths in 4519 battery plant workers and 2300 lead production or smelter workers during the years 1947 to 1980. Causes were coded to the seventh (1955) revision of the International Classification of Diseases. There were significant excess deaths for "other hypertensive disease" (444-447) and "chronic nephritis" (592-594) in both cohorts, the standardized mortality ratios (SMRs) being 320 and 475, respectively, for the former causes and 222 and 265 for the latter. Proportionate mortality analysis, which adjusted for race, also showed elevated ratios, 241 and 388 for the former causes and 296 and 186 for the latter. Deaths from other hypertension-related diseases did not show comparable excesses. Renal cancer deaths were fewer than expected, SMRs being 41 and 74, respectively.

A review of chest films from 152 workers who had been employed five or more years in perlite mining or processing showed none with small opacities of profusion 1/0 or higher. There were 14 films with doubtful changes (0/1), but these showed no correlation with type or duration of employment. Pulmonary function was measured in 122 current employees from the same plants. Multiple regression analysis showed no significant association between years of employment in perlite and either forced vital capacity (FVC) or forced expiratory volume (FEV1). There was a significant association between pack-years of cigarettes and both measurements. In 66 workers tested in 1975 and again in 1983, there was an average annual decrease in FVC of 32 mL, with 26 mL predicted by the Knudson formula, which is based on nonsmokers. The average annual decrease in FEV1 was 24 mL with 26 mL predicted. Comparison of groups with differing smoking patterns showed that the decreases in both FVC and FEV1 were associated with smoking. The 28 men who had added four or more pack-years in the interval between tests showed decreases in FVC and FEV1 of 44 mL/year and 31 mL/year, respectively, with 26 mL/year predicted for both groups. Those with less than four added pack-years (which included 26 nonsmokers) had decreases in FVC and FEV1 of 23 mL/year and 19 mL/year with 26 mL/year and 27 mL/year predicted.

A population of 10,173 men, employed in 37 plants, was identified as having worked for at least one year in jobs involving probable exposure to vinyl chloride monomer (VCM) prior to January 1, 1973. Of the 9677 men whose vital status was determined, 707 were known to have died. For 699, death certificates were obtained. The standardized mortality ratio (SMR) for all causes was 89, that for all malignancies was 104. The only type of malignancy found in significant excess was in the category of malignant neoplasms of the brain and other parts of the nervous system; 12 deaths occurred where 5.9 were expected, for an adjusted SMR of 203. There were slight but inconclusive upward trends in all malignancies, and for malignancies of the respiratory tract, digestive tract, and central nervous system associated with reported levels of maximum exposure to VCM. When groups in whom less than 20 years had elapsed from the first exposure were compared with those with 20 or more elapsed years, and 25 or more elapsed years, no significantly different SMR's were detected for major primary sites of malignancy. Plans for an updated study of mortality, to include deaths in the period 1973-1979 are briefly discussed.