I think that the coupling of "physical" with "chemical" and the detail of fire hazard suggest "physics" as the intended meaning.

--------------------------------------------------
Note added at 2004-02-20 14:41:50 (GMT)
--------------------------------------------------

It appears that the label addresses various kinds of hazards:

Physical and Chemical Hazards: Hazard arising from the physical and chemical properties of the substance. In this case, combustibility is the most relevant.

Hazards to humans: Hazard arising from contact with humans (such as when ingested).

Environmental hazards: Hazards to water, soil, etc.

Reference:

A physical Hazard arises when use of a chemical is potentially dangerous due, for example, to the possibility of explosion, fire or violent reaction with water. Peroxides, sulfuric acid, diethyl ether and phosphorus pentachloride are examples of materials which present physical hazards. Often, of course, such materials will also present health hazards due to their toxicity.

ptcl.chem.ox.ac.uk/MSDS/glossary/physical_hazard.html

numerous google definitions, different wording, essentially same meaning:

e.g.
A chemical is a physical hazard if it possesses flammable, combustible, explosive, oxidizing, pyrophoric or reactive properties, or if it is an organic peroxide or compressed gas.

http://www.lbl.gov/ehs/chsp/html/hazard_eval_.shtml

--
A chemical is a physical hazard if it is a combustible liquid, a compressed gas, an explosive, an organic peroxide, an oxidizer or pyrophoric, flammable, or reactive.

http://www.lbl.gov/ehs/chsptrain/html/hazard_evaluation.htm

This means that in addition to being able to say, poison the environment as to aggravate one's migraines, this product presents immediate danger of bodily injury on contact and/or when inhaled, etc.

Physical phenomenon is one in which there are no change in chemical composition.
Example: the explosion of a gas due to an extremely high pressure condition.
Chemical phenomenon is one in which there are some change in chemical composition.
Example: combustion of a flammable material due to the presence of oxygen. In combustion, the flammable material and the oxygen combine each other, and 'products of combustion' are generated, like CO2, CO and H2O.

Ref.: experience in translating Material Safety Data Sheets (MSDS's)-engineering experience.

--------------------------------------------------
Note added at 2004-02-21 15:51:11 (GMT)
--------------------------------------------------

Correction:

a hazard that involves a physical (not necessarily bodily) phenomenon

This is in reference to demyanov\'s disagree.
I think that the title \'Physical or Chemical Hazards\' refers directly to the basic scientific definitions of physical and chemical phenomena and their differences. They are independent of the existence of a human body in the surroundings.
Both physical and chemical hazards could be \'bodily\' -and usually they are- when a human body is present.