F o r s a le by th e S u p erin te n d e n t of D o c u m e n ts, U .S . G overnm ent P rin tin g O ffice, W ash in g to n , D .C . 20402 DHEW (NIOSH) Publication No. 77-151 PREFACE The Occupational Safety and Health Act of 1970 emphasizes the need for standards to protect the health and safety of workers exposed to an ever-increasing number of potential hazards at their workplace. The National Institute for Occupational Safety and Health has projected a formal system of research, with priorities determined on the basis of specified indices, to provide relevant data from which valid criteria for effective standards can be derived. Recommended standards for occupational exposure, which are the result of this work, are based on the health effects of exposure. The Secretary of Labor will weigh these recommendations along with other considerations such as feasibility and means of implementation in developing regulatory standards. It is intended to present successive reports as research and epidemiologic studies are completed and as sampling and analytical methods are developed. Criteria and standards will be reviewed periodically to ensure continuing protection of the worker. I am pleased to acknowledge the contributions to this report on alkanes (C5-C8) by members of the NIOSH staff and the valuable constructive comments by the Review Consultants on Alkanes (C5-C8), by the ad hoc committees of the American Industrial Hygiene Association and the American Occupational Medical Association and by Robert B. O'Connor, M.D., NIOSH consultant in occupational medicine. The NIOSH recommendations for standards are not necessarily a consensus of all the consultants and professional societies that reviewed this criteria document on alkanes. A list of Review Consultants appears on page vi.#
(1) For the purpose of determining the type of respirator to be used, the employer shall measure, when possible, the concentration of the airborne alkane or mixture of alkanes in the workplace both initially and thereafter whenever process, worksite, or control changes occur which are likely to result in increases in the alkane concentrations; this requirement does not apply when only atmosphere-supplying positive pressure respirators are used.
The employer shall ensure that no worker is exposed to alkanes at concentrations in excess of the workplace environmental limits because of improper respirator selection, fit, use, or maintenance.
(3) A respiratory protection program meeting the requirements of 29 CFR 1910.134 shall be established and enforced by the employer.
The employer shall provide respirators in accordance with Table 1-1 and shall ensure that the employees use the respirators provided.
(5) Respiratory protective devices described in Table 1-  (1) Gas mask with chin-style or front-or back-mounted organic vapor canister and full facepiece (2) Supplied-air respirator with full face piece, helmet, hood, or suit operated in continuous-flow, demand (negative pressure), or pressure-demand mode (positive pressure) Self-contained breathing apparatus operated in demand mode (negative pressure) with full facepiece (1)
Self-contained breathing apparatus with full facepiece operated in pressure-demand or other positive pressure mode (2)
Combination Type C supplied-air respira tor with full facepiece operated in the pressure-demand or other positive pressure mode and an auxiliary self-contained air supply operated in the pressure-demand or other positive pressure mode (1) Self-contained breathing apparatus with full facepiece operated in the pressuredemand or other positive pressure mode (2) Combination Type C supplied-air respira tor with full facepiece operated in the pressure-demand or other positive pressure mode and an auxiliary self-contained air supply operated in the pressure-demand or other positive pressure mode (1) Any gas mask providing protection against organic vapors (2) Any self-contained breathing apparatus as described in Table 1- (1) Safety showers and eyewash fountains, as well as fire extinguishers containing chemicals approved for Class B fires, shall be installed in bulk loading and unloading areas. Safety showers, eyewash fountains, and fire extinguishers shall be checked to ensure that they are in working order before alkanes are loaded or unloaded.
(2) If a leak in an alkane container occurs during the loading or unloading process, the operation shall be stopped and resumed only after necessary repair or replacement has been completed.
(3) Bonding facilities for protection against sparks from discharge of static charge during the loading of tank vehicles shall be provided as required by 29 CFR 1910.106.

# (d) Storage
Containers shall be stored in accordance with the applicable provisions of 29 CFR 1910.106 and shall be protected from heat, mechanical damage, and sources of ignition.

# (e) Disposal
Spills shall be flushed with water. Where it is not possible to flush a spill with water, the area should be cordoned off and ventilated until it is cleaned by other means, such as a venturi-type vacuum system.

# (f) Vessel Entry
(1) Entry into confined spaces, such as tanks, pits, tank cars, and process vessels which have contained alkanes, shall be controlled by a permit system. Permits shall be signed by an authorized employer representative, certifying that preparation of the confined space, precautionary measures, and personal protective equipment are adequate, and that prescribed procedures will be followed.
(2) Confined spaces which have contained alkanes shall be thoroughly ventilated, cleaned, washed, inspected, and tested for oxygen deficiency and for the presence of alkanes and other contaminants prior to entry.
(3) All efforts shall be made to prevent inadvertent release of alkanes into the confined space while work is in progress.
Alkane supply lines shall be disconnected and blocked off while such work is in progress.
(4) Confined spaces shall be ventilated while work is in progress to keep airborne alkane concentrations at or below the recommended environmental limits and to prevent oxygen deficiency.
(5) Individuals entering confined spaces where they may be exposed to alkanes shall wear respirators as outlined in Section 4(b) and lifelines tended by another worker outside the space who shall also be equipped with the necessary protective equipment.

# (g) Emergency Procedures
For all work areas where a reasonable potential for emergencies exists, procedures as specified below, as well as any other procedures appropriate for a specific operation or process, shall be formulated in advance and employees shall be instructed in their implementation:
( suggested that the exposure to hexane had resulted in demyelination and axonal degeneration, with demyelination being generally more pronounced.       for the exposure at 100 ppm and for the control mice. It then decreased to 1.2 at 250 ppm and to 1.0 at 500 ppm. However, at 1,000 and 2,000 ppm, a reversal of the flexor and extensor means took place to produce chronaxie ratios of 0.5 and 0.6, respectively. Also, the electrical reaction time, ie, the time that elapsed between electrical stimulation of muscle tissue and the resulting electrical discharge, was longer in the muscles of mice exposed to hexane at 1,000 and 2,000 ppm than in normal muscle. Marked muscular atrophy also was observed in those exposed to hexane at 1,000 and 2,000 ppm.

# Carcinogenicity, Mutagenicity, Teratogenicity and Other

# Effects on Reproduction
No studies have been found that are related to the carcinogenic, mutagenic, or teratogenic potential of pentane, hexane, heptane, or octane.
Since these compounds are not related chemically to compounds known to have' carcinogenic, mutagenic, or teratogenic activity, there is no present reason to suspect that they will be found to have such activity.

# Summary Tables of Exposure and Effects
The effects of exposure to pentane, hexane, heptane, and octane on humans, which were presented in detail in Chapter III, are summarized in Tables III-3, III-4, III-5, and III-6, respectively; those of exposures to pentane, hexane, heptane, and octane on animals are shown in Tables III-7, III-8, III-9, and 111-10, respectively.     Since a TLV for heptane of 400 ppm had been chosen, the TLV for octane was lowered to 300 ppm.    Protective equipment must be specified as to type and materials of construction.

# IV FIRE AND EX

# VIII.

# REFERENCES
(1) The date and time of sample collection.
(2) Sampling duration.
(3) Volumetric flow rate of sampling.
(4) A description of the sampling location.
(5) Ambient temperature and pressure.