Handbook of Solvents - George Wypych - ChemTech - Ventech!

20.5 Lymphohematopoietic study of workers exposed to benzene 1365
since the scope of this chapter is the hematopoietic effects, the reader is referred to other
sources. 3
20.5.3 HEMATOPOIETIC EFFECTS OF BENZENE
Benzene is a proven human carcinogen. The toxicity of benzene has been known since the
19th Century when aplastic anemia was first reported. 4,10 Indeed the causal link between
benzene and bone marrow toxicity in the form of hematoxicity and bone marrow suppression
was described already in 1897. 11 In 1928, Delore et al. described leukemia as a result of
benzene exposure. 12 In 1932 Lignac 13 reported lymphoblastoma in association with benzene
exposure. Several studies have reported the association between exposure to benzene and
hematopoietic toxicity and leukemia. 14,15 Acute myeloid leukemia has been the most frequent
form of leukemia found to be related to benzene exposure. Other forms of leukemia
have been described in association with benzene exposure, such as erythroleukemia,
thrombocytopenia, acute myeloid leukemia, myelodysplastic syndrome, acute
lymphoblastic leukemia, chronic lymphocytic leukemia, and Hodgkin’s and non-Hodgkin’s
lymphoma. As a result of the high toxicity of benzene the American Petroleum Institute
in their paper on benzene exposure in 1948 have concluded that the only safe level of
exposure to benzene is no exposure at all. 16 The language utilized was as follows, “In as
much as the body develops no tolerance to benzene, and as is there is a wide variation in individual
susceptibility, it is generally considered that the only absolutely safe concentration
for benzene is zero.”
The following hematological conditions have been described in association with benzene.
17-40
1. Acute myelogenous leukemia.
2. Erythroleukemia.
3. Aplastic anemia.
4. Acute monocytic leukemia.
5. Chronic myelogenous leukemia.
6. Myelofibrosis and myeloid metaplasia.
7. Thrombocythemia.
8. Acute lymphoblastic leukemia.
9. Chronic lymphocytic leukemia.
10. Lymphomas and related disorders.
11. Multiple myeloma
12. Myelodysplastic syndrome.
20.5.4 CARCINOGENIC EFFECTS OF BENZENE
Several well conducted epidemiological scientific studies and data have provided the epidemiological
basis for benzene as a hematopoietic and lymphopoietic cancer. In his paper entitled
“Benzene Health Effects”, Mehlman described a wide range of the hematotoxicity of
benzene. 41 Nilsson et al. 42 described leukemia, lymphoma and multiple myeloma in seamen
exposed to benzene in tankers. In this study, an increased incidence of lymphatic and
hematopoietic malignancies was described and, while it is true that the cargo vapors from
gasoline and other light petroleum products and chemicals have been studied, benzene exposure
during loading, unloading and tank cleaning operations was concluded to be the
likely source of the carcinogenic exposure. Rinsky et al. 43 described various hematological
malignancies in their study of benzene exposure and showed that the overall standardized