Can occur through eating or smoking with contaminated hands or in contaminated work areas. Most exposure standards are based on the inhalation route of exposure. In many instances, the PEL and TLV are represented as the same number. In the instances where one is lower than the other, it is a prudent safety practice to maintain exposures at the lowest level achievable. If a significant route of exposure for a substance is through skin contact, the TLV or PEL will have a skin notation.
Examples are pesticides, carbon tetrachloride, cyanides, ethylenediamine and thallium.
Appendix K of this document lists PELs and TLV's for many hazardous chemicals. The latest editions lists both TLV's and PELs. Types of Effects Acute poisoning is characterized by rapid absorption of the substance when the exposure is sudden and severe. Normally, a single large exposure is involved. Examples are carbon monoxide or cyanide poisoning.